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Lower Water Pressure Problems/Cleaning Shower Heads


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Posted

My small hotel uses a gravity-fed cold water supply system for the guest bathrooms, with a 3,000 litre header tank mounted at a height of 5 metres, supplied from our well by an auto-demand pump.

We have previously used a large pump located at the base of the water tower (tank outlet), to increase the water flow rate to the showers. However, this large pump also results in blown pipe fittings on occasions, even though I have reduced the flow rate by partly closing the output valve.

I'm not sure how to calculate shower head pressure, but I am sure that a tank mounted at 5 metres height should provide sufficient head of water for my 10 guest rooms. (In the UK, our loft-mounted water tank was about 1 meter above the shower head and there was certainly a good flow of water).

So I think the problem is more of obstructions in my gravity-fed system, such as partly closed valves and sediment build-up inside shower fittings.

What is the best way to clean the shower heads? Can I immerse the heads in some cleaning solution to remove calcium build-up and sediment deposits?

Thanks

Simon

Posted

Ordinary cheap vinegar will do the trick, leave the shower heads submerged for an hour or two and than rinse against the flow direction first.. :jap:

Posted

Ordinary cheap vinegar will do the trick, leave the shower heads submerged for an hour or two and than rinse against the flow direction first.. :jap:

Agree vinegar will do the trick, I normally leave the head in vinegar over night, in case the head is almost blocked be sure to pour vinegar inside the head

Posted

Ordinary cheap vinegar will do the trick, leave the shower heads submerged for an hour or two and than rinse against the flow direction first.. :jap:

Agree vinegar will do the trick, I normally leave the head in vinegar over night, in case the head is almost blocked be sure to pour vinegar inside the head

seconded, and do the same with all tap filters

but for waterpressure

5 meters over shower provides 0,5 bar in shower. Desired for a good shower is 2,5-2,8 bar. A Mitsubishi 305Q pump at bottom of tank would be the least expensive solution at approx 6,5-7k baht, and will provide less than 3 bar wich all piping should be able to handle. At least thats my solution in one of my houses, 7 bathrooms pluss rainshower next to pool +++

Posted

This is a little away fom your question, but the point about blown pipe fittings needs discussing.

"We have previously used a large pump located at the base of the water tower (tank outlet), to increase the water flow rate to the showers. However, this large pump also results in blown pipe fittings on occasions, even though I have reduced the flow rate by partly closing the output valve."

Reducing the flow rate by partly closing the output valve will not reduce the pressure in the pipeline when the pump is running without any taps being opened - the pipes / fittings will still see full pump pressure.

Posted

This is a little away fom your question, but the point about blown pipe fittings needs discussing.

"We have previously used a large pump located at the base of the water tower (tank outlet), to increase the water flow rate to the showers. However, this large pump also results in blown pipe fittings on occasions, even though I have reduced the flow rate by partly closing the output valve."

Reducing the flow rate by partly closing the output valve will not reduce the pressure in the pipeline when the pump is running without any taps being opened - the pipes / fittings will still see full pump pressure.

yepp, partly closing a valve does not reduce the pressure damaging piping and fixtures, only the flow rate. Only a pressure valve does, and that is why I suggested a Mitsu 305Q which has a pressure valve set to make pvc piping survive

Posted

Proper PVC will survive at a much higher pressure than any 305 is going to provide (totally inadequate in my - and more importantly wifes - opinion). :D Having had two 405 models years ago we changed to 60psi pump and most happy with the change. Did spring a leak when typical workmanship on a corner was to let the glue hold rather than tightly fit together and find house brand plumbing flex hose from a major (food) chain to be useless but the aggravation is worth it to have serious water flow from point of use heaters.

Posted

Proper PVC will survive at a much higher pressure than any 305 is going to provide (totally inadequate in my - and more importantly wifes - opinion). :D Having had two 405 models years ago we changed to 60psi pump and most happy with the change. Did spring a leak when typical workmanship on a corner was to let the glue hold rather than tightly fit together and find house brand plumbing flex hose from a major (food) chain to be useless but the aggravation is worth it to have serious water flow from point of use heaters.

I finde 305Q to work fine when installed on roof. OP has an additional 5 meter (0,5 Bar) pressure from tower

For a 2 or 3 storey building installed on groundfloor, it is inadequate. Over to Grundfoss ;)

Posted

Proper PVC will survive at a much higher pressure than any 305 is going to provide (totally inadequate in my - and more importantly wifes - opinion). :D Having had two 405 models years ago we changed to 60psi pump and most happy with the change. Did spring a leak when typical workmanship on a corner was to let the glue hold rather than tightly fit together and find house brand plumbing flex hose from a major (food) chain to be useless but the aggravation is worth it to have serious water flow from point of use heaters.

I finde 305Q to work fine when installed on roof. OP has an additional 5 meter (0,5 Bar) pressure from tower

For a 2 or 3 storey building installed on groundfloor, it is inadequate. Over to Grundfoss ;)

My goodness, you two must need water hitting your body at bullet speed. I have a 255 model for my two story house, the pump is setting at ground level feed by a tank next to it, the pump pressure switch is set to the proper 2.1 bar and 2.8 bar cut-on and cut-off pressures (pretty much the same pressures as the 305 and 405 except these two models have more capacity output than a 255), and the two showers in my two upstairs bathroom have strong pressure output....just fine for a relaxing hot shower...and for a cold shower it's extra strong pressure since part of the water is not going through the heater. ;)

Posted

Proper PVC will survive at a much higher pressure than any 305 is going to provide (totally inadequate in my - and more importantly wifes - opinion). :D Having had two 405 models years ago we changed to 60psi pump and most happy with the change. Did spring a leak when typical workmanship on a corner was to let the glue hold rather than tightly fit together and find house brand plumbing flex hose from a major (food) chain to be useless but the aggravation is worth it to have serious water flow from point of use heaters.

I finde 305Q to work fine when installed on roof. OP has an additional 5 meter (0,5 Bar) pressure from tower

For a 2 or 3 storey building installed on groundfloor, it is inadequate. Over to Grundfoss ;)

My goodness, you two must need water hitting your body at bullet speed. I have a 255 model for my two story house, the pump is setting at ground level feed by a tank next to it, the pump pressure switch is set to the proper 2.1 bar and 2.8 bar cut-on and cut-off pressures (pretty much the same pressures as the 305 and 405 except these two models have more capacity output than a 255), and the two showers in my two upstairs bathroom have strong pressure output....just fine for a relaxing hot shower...and for a cold shower it's extra strong pressure since part of the water is not going through the heater. ;)

in a 2 storey building with 7 bathrooms and poolshower, I replaced 305Q with Grundfoss to make it possible to use several bathrooms at same time. Pressure fine, but to little flow in 305Q installed groundfloor. One hotwatertank for all bathrooms/kitchen.

in a 3 storey building with 3 bath, the two upper floors instant heaters (hate those silly instantheaters) have to low flow to heat if downstairs taps are opend during shower. Have to replace pump or change hotwater solution. Presently 305Q on groundfloor

but on the roof of 3rd floor in a 7 bath house 305Q works fine :)

and in a 2 bath bungalow without hotwater 150 works fine :)

Posted
... and the two showers in my two upstairs bathroom have strong pressure output....just fine for a relaxing hot shower...and for a cold shower it's extra strong pressure since part of the water is not going through the heater.

Thanks for mentioning that. It brings up a question I've wondered about: Do all hot water shower units result in a lower output water pressure? i.e. By virtue of design (small copper tubing) will water pressure be reduced when going through a shower fixture?

All my previous abodes have had multi-point heaters with shower controls that mixed hot & cold water. My current rented townhouse has individual shower heaters and its my first experience with them. I *think* the upstairs shower heater needs to be replaced as the pressure seems too low*, but I'm wondering if I'd see much of an increase with a new unit? (The downstairs shower had its heater yanked, so it's currently a full-pressure "al fresco" shower unit with great output pressure.)

What is the usefulness of the "air bubble" feature of some shower units? Is it a useless gimmick, or does it actually add to the water pressure as the sales people say?

*The sink and toilet in the same upstairs bathroom seem to have full (high enough) water pressure. The hand-held shower, however, even with a new spray head only shoots up about 4" when flipped over to spray upwards. All previous showers I've had, if I dropped the shower head it would shoot up to my head from the floor.

Posted

I really can't speed to all water heaters as in my lifetime I've only used either a "tank" water heater that feeds the whole house or the instantaneous wall mounted warm water heater like I have now in Thailand. Of course a "tank" water heater like used in the States has plenty of hard water but of course that tank of hot water is being heated/using energy most of the time to keep the water hot.

The instantaneous wall mounted heater I currently have in Thailand use the internal 1/4'' heating element tubing which basically acts as a water restriction. All heaters that I seen on display in places like Homepro seem to use the same internal 1/4" tubing. My heater is basic heater with no controls on it. When water flow occurs through it, the heater automatically turns on. Cold water going in the heater inlet, hot water comes out the heater outlet, the hot water outlet feeds right back to a wall inlet which leads to my hot water facet a few feet down, and there the shower hose hooks on an outlet between the hot and cold water faucets. So, when my 6000W Fagor heater kicks-in, if you only have the hot water faucet turned on you will get water at about 35 to 40F higher temperature than the incoming water. If it's been a 90F day and the storage tank water is around 90F, then you get 130F water coming from your hot water faucet. And 130F water is way too hot to stand under; it would burn you. You need to turn on the cold water faucet to mix in some cold water to get the temperature to the level that is comfortable for you. Normally, I turn the hot water faucet on full blast to get full flow going through the heater and then turn on the cold water faucet to adjust the temperature/mix in the cold water...this ends up in a strong shower flow on the ol' body. Now I will admit in cold snaps, when the daily temperature has hovered around 70F all day, that 110F water coming from the heater needs very little cold water added in for a comfortable temperature which results in a significantly lower shower flow. I would no longer say it a strong flow anymore but still more than adequate. And this only occurrs maybe 10 days out of the year for me here in Bangkok. A 6000W heater is a good size/wattage but you need a 30A dedicate circuit to feed each heater as the heater uses around 27A when turned on.

Now I know other bathroom showers don't have separate lines built into the wall to allow hookup of a heater to allow mixing of hot and cold water at the faucets/shower head. Instead the heater just adjusts the temperature of the water.. Basically, the one incoming cold water line feeds into the heater, and then a person uses the heater controls to adjust the water temperature. Simple enough. On this type of heater, the water is always going through the heater whether the heater is heating or not, which means a "restricted" water flow for hot or cold water output.

I will say on those hot days when I only turn on my cold water faucet to max with my ol 255 pump providing a 2.1 (30psi) to 2.8 bar (40psi) or a 35 psi average pressure that it provides a "really" strong shower in my bathrooms upstairs. When I turn on the hot water and adjust the cold water flow down, I'm down to just a strong, hot shower. And I just use a regular, cheapie plastic shower head with the internal restrictor removed. A lot of things can affect flow. Even with good pressure, if the pipes inside you wall are too small they are somewhat reducing the capaity of water flow which ends up in lower flow when traveling through the heater tubes and the show head. In my house, the water lines feeding my showers is a 3/4" line that gets knocked down to a 1/2" lines for just a few feet before the faucet outlets. I know many residences just have 1/2' water lines feeding throughout the house. For me and my house lines the 255 pump is more than adequate water pressure & capacity, and my Fagor water heaters give me hot water without needing to learn how to use any spaceship controls. (grin)

(grin).

Posted
The instantaneous wall mounted heater I currently have in Thailand use the internal 1/4'' heating element tubing which basically acts as a water restriction. All heaters that I seen on display in places like Homepro seem to use the same internal 1/4" tubing.

So, by nature of its design, a standard shower water heater will restrict the output water flow.

My question now to those folks using these shower water heaters, what is normal output water pressure in practical terms? If you take the hand held shower head and invert it so it's pointing toward the ceiling, how high does the water spray? My current one only sprays up about four inches. Is that normal, or if I replace it, will I see a noticeable increase in output pressure? I'd hate to go through the bother and expense of replacing the heater to find that a four-inch spray is all that should be expected.

Posted

Just checked my unit and sends water up 1 meter if held at chest level. This is a normal wall 3.5kw point of use unit with one feed on ground floor using Grundfoss pump at about 60psi. So yes, much more than 4 inch.

Posted

My wall mounted shower heater has heaps of flow and pressure PROVIDED that I regularly clean the little dome shaped filter that is installed (look for it) inside the input side water connection of the heater.

"Salt" residue in the shower head I clean with "Toilet Duck" cleaner. It's a much stronger acid than Vinegar thus acts faster

Good luck!

Posted

I actaully had to go and check one shower :)

305Q on the roof approx 6 meters above this shower, 200 liter Fagor tank on the roof, 3/4 pipes common cold, hot 1/2 only, 1/2 pipes to each bathroom. Shower held at faucet height 110 cm, open both hot and cold, barely hits ceiling at 2,6 meter. Hope ceiling dryes quickly

Posted
The instantaneous wall mounted heater I currently have in Thailand use the internal 1/4'' heating element tubing which basically acts as a water restriction. All heaters that I seen on display in places like Homepro seem to use the same internal 1/4" tubing.

So, by nature of its design, a standard shower water heater will restrict the output water flow.

My question now to those folks using these shower water heaters, what is normal output water pressure in practical terms? If you take the hand held shower head and invert it so it's pointing toward the ceiling, how high does the water spray? My current one only sprays up about four inches. Is that normal, or if I replace it, will I see a noticeable increase in output pressure? I'd hate to go through the bother and expense of replacing the heater to find that a four-inch spray is all that should be expected.

Yes, any time you reduce the size of the pipe, like using an adapter to downsize from a 1" pipe to a 1/2" pipe you have just reduced your water volume/capacity although your overall system/water pump pressure is still the same...it's not like your water pump or tank setting on top or at the bottom of your condo building all of a sudden decided to reduce its overall pressure output. How much water ends up coming out of your pipe primary depends on pressure and volume/capacity which are both affected by flow restrictions. Maybe to use an exaggerated example, say the tubing inside the heater was only 1/16", you wouldn't get much water volume coming out although your overall system water pressure is unchanged.

Kinda like when you adjust the nozzle on a water hose to different spray patterns; the pressure feeding the nozzle input is still the same, but since the nozzle restriction size is being varied, the water pressure/volume/capacity is also being changed within the nozzle/at the nozzle output although your overall feeding system pressure is staying the same...that pump or tank is still feeding X-amount of pressure to the hose. And yea, there are big pressure variations occurring "right at the nozzle/inside the nozzle"due to the changing of the nozzle restriction size, but your overall system/water pressure pressure is staying steady.

I did your requested test in one of my upstairs showers. To re-mention, I have a Mitsubishi WP-255 water pump which cuts on at 30psi (2.1 bar) and cuts off at 40psi (2.8 bar), for an average water pressure of 35psi. With only the hot water faucet on and all water flow going through the heater with 1/4 inch tubing, my plain jane, cheapie, non-adjustable, plastic shower head (which needs cleaning) shot water up 10 to 13 inches as the pump cycled through its cut on and cut off pressures. So an average of almost 12 inches. And "without" the shower head, the water from the shower hose shot up 8 to 11 inches as the pump pressure varied from 30 to 40 psi. Remember, my shower is on the second story of the house with the pump at ground level so I expect I really have a little less than an average 35psi reaching my showers due to this height. One of these days I need get an adapter for my pressure gauge and check the pressure reaching the second story of the house. But, there was not much "height" difference in how far the water would shoot up between the hose-only and then with the shower head connected.

Then I turned the hot water off, turned the cold water faucet on about one turn see how far the shower head output would shoot up and I had to turn it off will quickly as it shot to the shower ceiling which is around 8 ft. This is with the shower head on and the shower head putting out its normal wide, multi-stream pattern. With only the cold water faucet on there is no additive flow going through/coming from the hot water heater/faucet. Sure hope my ceiling paint was water resistant. (grin) I then turned the cold water faucet on "a little slower" to make sure it wasn't just a surge that caused the water to shoot up so high, but I got the same result in the shower head water output reaching the 8 ft ceiling after turning on the faucet about one turn. I'm would guess it would have shot up around 10 ft if not for the ceiling being in the way. That sure helps to illustrated how going from an 1/2 inch feeder pipe through 1/4 inch heater pipes which fed back into a 1/2 inch pipe/shower hose can reduce the water volume/capacity/flow. And just think how hot water flow would be reduced even more if the heater 1/4 inch internal tubing became partly clogged, the shower head has a restrictor in it or is clogged, or you just have overall low pressure causing he whole problem. For my normal showering I have the hot water faucet on full blast for max flow through the heater and then I adjust the cold water faucet for temperature control by turning it on about a 1/2 to 1 turn. This results in a strong hot shower. I can't handle a shower with only the hot water faucet turned on because although the shower output is adequate (but not strong) the water is way too hot coming from my 6000W heater!!!!....you have to mix in cold water which significantly increases the shower head flow. Now a person using a 3500W heater would need to turn on less cold water to adjust temperature down, which would reduce the shower head water flow....but if they are using a 60psi pump they could keep the flow up with litte cold water being mixed in. Quite a few factors can affect a person's hot water flow to what feels good to a person's body...a lot depends on pump pressure, pipe sizes, heater wattage, shower head spray pattern, strength of shower desired, etc.

Have you checked your water pressure? Since my shower hose output with no head attached shot water up 8 inches at 30 psi and 11 inches at 40 psi, this appears to show a 1 inch upward stream for every approx 3.75 psi. Assuming you ain't got no clogged heater or shower head and based on your water stream of only 4 inches with shower head attached, sounds like you are probably running around only 15-20psi. Maybe take the shower head off and remeasure the distance the water stream shoots up...I got 8 inches at 30psi and 11 inches at 40psi. If you get about the same then your shower head is restricted/clogged. By doing this comparisons it should give you the ballpark water pressure reaching your shower head but it sure sounds like only around 15-20psi assuming no restriction/clog. You are not going to get a strong shower from a instantaneous/wall mounted hot water heater if only running around 15-20psi. You'll need to increase your water pressure up to around an average 35psi. I say average because most household type pumps like the Mitsubishi WP-255/305 have water pressure cut on and cut off pressures of 30psi and 40 psi, respectively, for an average of 35psi. Now, if you get a smaller pump the pressure setting could be lower as the next group of pumps and their pressures settings operate around the 1.3 bar (19psi) to 1.9 bar (28psi) range, for an average pressure of around 24 psi. At 24 psi, the strength of your hot water shower is probably going to be adequate but not strong considering the water flow will have to go through the 1/4 inch heater tubing on its way to the shower head. Or, go to a high end/high pressure pump like a Grundfoss pumping out a continuous 60psi, but your pump cost will approx double. Yea, you can buy cheaper, high pressure Thai pumps that put out 60psi (dozens upon dozens of different models sold in hadware stores) but they will be noisier, less reliable, and you should use them with a pressure tank.

Good luck in getting your shower head water to shoot to the ceiling! Good, strong pressure is usually the answer versus the heater or shower head being clogged. ;)

Posted

Perfect! Thanks for the reports. You all get passing grades on your homework assignment. :thumbsup:

(katabeachbum: My apologies. I hope your ceiling dried with no water damage!)

I think I forgot to mention that I had looked for a screen filter in the connections for the hose that runs from the wall to the heater, and didn't find one (perhaps a contributing factor...) and that I installed a new shower head to eliminate those two as possible culprits. The water pressure to the sink and toilet in the same room seem to be quite strong. The bum sprayer is quite, uhm, invigorating.

Based on the reports above, I feel more confident that I'll see an improvement in the output water pressure/volume if I install a new heater.

Currently, I'm taking "Thai showers" in the other hong nahm that doesn't have a heater, since the water pressure is so much greater. My water tank is above ground, so the water is close to room temp and not *too* much of a shock to my body.

Again, thanks for the reports. A practical test like that means much more to me than if you all had taken pressure gauges and reported back the exact water pressure out of the nozzle.

Oh, and any opinions on the value of the "air bubble" feature on some of the shower heaters? Is it a gimmick only, or does it actually improve the shower experience (to use some marketing speak)?

Posted

I noticed this Stiebel shower heater on display at the entrance to HomePro. Price seems okay. Aren't Stiebel heaters solid & reliable?

post-33251-0-55081900-1303712075_thumb.j

Posted

My very limited experience with the bubble maker did not impress me. Water pressure was limited and it did not seem to make much difference.

As for Stiebel I had believed it would be good but the two times I have encountered them (in hotels) they have not worked well (but they were hot water only so needed mix valve and they never seemed to work right - not point of use for shower as the photo appears to be)

Posted

Based on the reports above, I feel more confident that I'll see an improvement in the output water pressure/volume if I install a new heater.

Why do you feel a new heater will make a difference? Unless the internal tubing is partially clogged, you won't see an increase in water output. Heaters are not like pressure washers that take water input and increase the pressure output via a pump/special nozzle. Heaters pretty much just let the the water flow through them while heating water. Buy yourself a 200 baht pressure gauge at a hardware store with a short piece of old hose and a couple of clamps to check your water pressure first. Buying a 3000 baht or up new heater may just result in the same shower performance you are getting right now if the issue is just low pressure. Don't be mislead by what appears to be strong pressure coming from your sink faucet and bum sprayer because it don't take much pressure for these to seem strong/produce a strong stream.

Posted

Perfect! Thanks for the reports. You all get passing grades on your homework assignment. :thumbsup:

(katabeachbum: My apologies. I hope your ceiling dried with no water damage!)

I think I forgot to mention that I had looked for a screen filter in the connections for the hose that runs from the wall to the heater, and didn't find one (perhaps a contributing factor...) and that I installed a new shower head to eliminate those two as possible culprits. The water pressure to the sink and toilet in the same room seem to be quite strong. The bum sprayer is quite, uhm, invigorating.

Based on the reports above, I feel more confident that I'll see an improvement in the output water pressure/volume if I install a new heater.

Currently, I'm taking "Thai showers" in the other hong nahm that doesn't have a heater, since the water pressure is so much greater. My water tank is above ground, so the water is close to room temp and not *too* much of a shock to my body.

Again, thanks for the reports. A practical test like that means much more to me than if you all had taken pressure gauges and reported back the exact water pressure out of the nozzle.

Oh, and any opinions on the value of the "air bubble" feature on some of the shower heaters? Is it a gimmick only, or does it actually improve the shower experience (to use some marketing speak)?

Try to flush your heater first, by connecting pressure water to heaters OUTLET for 10 minuets.

Often it is clogged by minerals, and most dissolve with vinegar

Posted

Thanks for mentioning that. It brings up a question I've wondered about: Do all hot water shower units result in a lower output water pressure?

The correct answer is that any of these instant water heaters will result in a reduced "Flow" which may appear to the naked eye as reduced pressure.. One only needs to remove the cover to see why this is so.

Gas fired on the other hand can pass much more heated volume.

Posted

The correct answer is that any of these instant water heaters will result in a reduced "Flow" which may appear to the naked eye as reduced pressure.. One only needs to remove the cover to see why this is so.

Yeap, the internal 1/4" tubing is about the size of a large straw that comes with your soft drink. Can't get a lot of water through a straw unless you have good pressure going into the straw.

Posted (edited)
Based on the reports above, I feel more confident that I'll see an improvement in the output water pressure/volume if I install a new heater.

Why do you feel a new heater will make a difference? Unless the internal tubing is partially clogged, you won't see an increase in water output. Heaters are not like pressure washers that take water input and increase the pressure output via a pump/special nozzle. Heaters pretty much just let the the water flow through them while heating water. Buy yourself a 200 baht pressure gauge at a hardware store with a short piece of old hose and a couple of clamps to check your water pressure first. Buying a 3000 baht or up new heater may just result in the same shower performance you are getting right now if the issue is just low pressure. Don't be mislead by what appears to be strong pressure coming from your sink faucet and bum sprayer because it don't take much pressure for these to seem strong/produce a strong stream.

Mainly because the water pressure coming out of the wall is sufficient that if I take the inlet hose off the heater and open the faucet, I can replicate katabeachbum's experience and spray the ceiling -- about a 3.5 to 4 foot vertical shoot. Reconnect the inlet hose, and the force coming out of the (new) shower hose (even with the shower head detached) is only four inches.

So, that's why I asked others to report how high their hot water heaters shoot vertically. Criminy, I just re-read your earlier long post and see that your water shoots 8 to 10 feet high! Hmmm, me = 3.5 to 4 feet, and you 8 to 10 feet, maybe there IS a water pressure issue...

I was aware that there would be SOME reduction of pressure going through the smaller copper tubes, just wasn't sure if my 4" spurt was normal.

Hmmm. I might still get a new heater, and if I still only get a 4" shower, put the old one in the other shower room. It's only money. :whistling:

Edited by wpcoe
Posted
Try to flush your heater first, by connecting pressure water to heaters OUTLET for 10 minuets.

Often it is clogged by minerals, and most dissolve with vinegar

Thanks for that suggestion, however the back flush didn't help at all. Not sure how to flush it with vinegar?

Posted (edited)
Based on the reports above, I feel more confident that I'll see an improvement in the output water pressure/volume if I install a new heater.

Why do you feel a new heater will make a difference? Unless the internal tubing is partially clogged, you won't see an increase in water output. Heaters are not like pressure washers that take water input and increase the pressure output via a pump/special nozzle. Heaters pretty much just let the the water flow through them while heating water. Buy yourself a 200 baht pressure gauge at a hardware store with a short piece of old hose and a couple of clamps to check your water pressure first. Buying a 3000 baht or up new heater may just result in the same shower performance you are getting right now if the issue is just low pressure. Don't be mislead by what appears to be strong pressure coming from your sink faucet and bum sprayer because it don't take much pressure for these to seem strong/produce a strong stream.

Mainly because the water pressure coming out of the wall is sufficient that if I take the inlet hose off the heater and open the faucet, I can replicate katabeachbum's experience and spray the ceiling -- about a 3.5 to 4 foot vertical shoot. Reconnect the inlet hose, and the force coming out of the (new) shower hose (even with the shower head detached) is only four inches.

So, that's why I asked others to report how high their hot water heaters shoot vertically. Criminy, I just re-read your earlier long post and see that your water shoots 8 to 10 feet high! Hmmm, me = 3.5 to 4 feet, and you 8 to 10 feet, maybe there IS a water pressure issue...

I was aware that there would be SOME reduction of pressure going through the smaller copper tubes, just wasn't sure if my 4" spurt was normal.

Hmmm. I might still get a new heater, and if I still only get a 4" shower, put the old one in the other shower room. It's only money. :whistling:

If I had to bet money on the outcome, you won't see any significant improvement with a new heater, unless the current heater is partially clogged and assuming you have good pressure (but my gut tells me you do not have good pressure). As a rule of thumb, when going from a 0.50 inch pipe size (i.e., the water feeder source to your heater) to the 0.25 inch heater internal tubing, your flow rate/volume is being reduced by approx one-third to one-fourth. The only way to offset the reduced flow rate is to increase the pressure of the feeder source which increases the velocity of the water through the pipes.

You can use the calculator at the following link to get an idea of how pipe/tubing size can affect flow rate---it's not a linear function like maybe thinking the flow rate is reduced by one-half when going from a 1 inch pipe to a 0.5 inch pipe. Select the calculator to give you a Flow Rate Result and enter pipe size in inches and use a velocity of 5 ft per second (pressure basically determines your water velocity although other factor are involved). The result will be a 0.5 inch pipe would produce a flow rate of 3.06 gallons/minute while a 0.25 inch pipe would only provide a flow rate of 0.765 gallons/minute....see what I mean by not being linear and how drastic the flow rate/volume reduction is. And if changing the water velocity number to 1 ft/sec the 0.50 inch the pipe puts out 0.612 gallons/minute and the 0.25 inch pipe puts out 0.156 gallons per minute...approx a 4 fold reduction. But notice how the velocity change (i.e., pressure) made such a big difference in water output. http://www.1728.com/flowrate.htm

Pressure...pressure....pressure is usually the answer to getting a strong shower. To use an analogy, putting new wheels (a new heater) on a car ain't going to make it go any faster unless you increase the horsepower (water pressure) of the engine. Good luck...sincerely hope you get the shower situation fixed...I just don't want you to think a new heater is the "for sure" fix. Remember, you are trying to push water through a soft drink size straw (i.e., the heater tubing) and and it takes pressure to make that happen.

Edited by Pib
Posted
Try to flush your heater first, by connecting pressure water to heaters OUTLET for 10 minuets.

Often it is clogged by minerals, and most dissolve with vinegar

Thanks for that suggestion, however the back flush didn't help at all. Not sure how to flush it with vinegar?

IN and OUT hoses both over heater level, OUT hose slightly lower than IN hose. Pour winegar blended with 50-70% water in IN and wait for it to come out from OUT hose, and leave it for a couple of hours. Then backflush again OUT to IN.

If this doesnt work, larger flow pump is needed. New heater wont make much difference as its still 1/4 inch or less reducing flow to much. 2,5 bar at ground floor is 2,1 bar 4 meters higher. Only 2,1 bar or actually down to 2,2 bar minus 4 meters equalling 0,4 bar is 1,8 bar when pump kicks in again, not sufficient to pass the small heater with acceptable shower flow. Higher pressure or better flow is required. As higher pressure would likely hurt your groundfloor piping and faucets, higher flow it is.

Posted (edited)

I would say water towers in USA are 20 to 30 meters tall. So pressure is not an issue for them.

If the OP decides to install a pump don't use a fixed pressure switch like the Mitsu's already mentioned.

He needs a pump with adjustable cut-off.

Like this tankless model.

This model is actually 2 pieces. The pump & the electronic controller. The controller will not let the pump run unless the suction is flooded. And it has adjustable cut-off.

Red light & green light to show it's state. Very cool pumps.

post-79990-0-20310000-1303787900_thumb.j

Edited by powderpuff
Posted

Actually, the Mitsubishi tank type pumps mentioned are not really fixed pressure. The mid/high capacity pumps are set to cut-on at around 2.1 bar (30psi) and cut-off at 2.8 bar (40psi)...gives you an average 35psi. The lower capacity pumps have a lower pressure range. And actually on most (not all) of the pumps you can adjust this by adjusting the screw on top of the pressure switch (you remove the plastic cap to reach the screw adjustment)...but you shouldn't set it to a higher pressure and you shouldn't adjust the pressure on any pump unless having a pressure gauge and know the max and mix pressure settings allowed per pump specs; otherwise, you'll just cause pump problems. Actually the pump you pictured would be closer to a fixed pressure (although the pressure can be adjusted) because when it cuts-on it produces a fixed/continuous pressure/stream of water and will stay on as long as the water is running even a little bit, where the pressure tank type pumps will cycle on and off...the tank types will cut on and off at above mentioned pressures and while cut off draw water from the tank that is under pressure....and will stay cut off for drawing down a half to one liter of water where the pictured pump would cut on unless it feeds into a pressure tank. Usually these pumps are of a higher wattage and pressure output than pumps focused towards residences like the majority of pumps sold in places like HomePro, Lotus, Big C, etc.

Pro's and con's to pump types, but from looking at the type of pumps used at most stand-alone homes and the type of pumps sold at places like HomePro, the tank type is by far the most popular (i.e., the pump assembly setting on top of a small 15-20 liter pressure tank). Seems the tankless type pumps are more focused toward irrigation, shrimp farming, and large fountains; or used to feed a large pressure tank of around 100 liters so the pump don't run continously....effectively turning the pump into a pressure tank type pump. And of course there are Mitsubishi type pumps which are pretty much continuous and only have a 1 liter tank/bottle to prevent the pump from kicking on all the time due to small leaks...these are popular also and designed for residences.

Question: Assuming you own/bought the pump/controller, what is the wattage, manufacturer, min & max pressure setttings, and cost of the pump/controller? Thanks.

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