Plumbing

[Silurian]

I need to install a new pump in our townhouse. Homepro recommends the 400hp one, my neighbor uses 250hp and my girlfriend's dad says 200hp is enough. I've been to my neighbor's house and the water pressure is adequate but not great. I was thinking about getting a 300hp one for good water pressure. The townhouse is three floors with 5 bathrooms. I think the guy at Homepro was over-estimating the pump. Does anyone have a good idea of how to calculate what size of pump to use? Will using too big of a pump cause more stress on the pipes causing them to weaken and break?

Another thing, I need to run a new pipe from the pump to the household water distribution system which is in back of the townhouse. The current pipe is under the floor and I was told not to use it since it is most likely broke. I don't want to rip up the floor since it is a nice granite floor. The ceiling between the first and second floors has a small dropped ceiling where I can run the water pipe. It would be easier to fix the ceiling drywall than repair the granite floor. Does anyone see any issue with running the pipe in the ceiling? I assume that the water flow will be okay to come up to the ceiling and then back down to inlet near the floor.

[whosyourdaddy]

I need to install a new pump in our townhouse. Homepro recommends the 400hp one, my neighbor uses 250hp and my girlfriend's dad says 200hp is enough. I've been to my neighbor's house and the water pressure is adequate but not great. I was thinking about getting a 300hp one for good water pressure. The townhouse is three floors with 5 bathrooms. I think the guy at Homepro was over-estimating the pump. Does anyone have a good idea of how to calculate what size of pump to use? Will using too big of a pump cause more stress on the pipes causing them to weaken and break?

Another thing, I need to run a new pipe from the pump to the household water distribution system which is in back of the townhouse. The current pipe is under the floor and I was told not to use it since it is most likely broke. I don't want to rip up the floor since it is a nice granite floor. The ceiling between the first and second floors has a small dropped ceiling where I can run the water pipe. It would be easier to fix the ceiling drywall than repair the granite floor. Does anyone see any issue with running the pipe in the ceiling? I assume that the water flow will be okay to come up to the ceiling and then back down to inlet near the floor.

3 floors would be about 200-250. You would want at least 17 psi pressure on the top floor or your hot water heater may shut on and off since there will not be enough pressure. The problem with higher pressure is that the pump will be coming on more often to maintain the pressure.

Dont see a problem with running the pipe between floors as long as it is connected well to the wall/ceiling.

[lopburi3]

I believe those pumps are rated in watts, not "hp" (your car is likely less than 200hp). Not sure when you say water distribution is in the rear what exactly you mean. Outside pipes to upstairs bathrooms and such? I assume the tank and pump are in the front? You should be able to run pipe in ceiling but make sure they fit connections tight as you don't want any leaks.

We have a 5 bath and 2 kitchen home and always used the largest Mitsubishi pump but even with that the water pressure is never more than about 35psi and much less when a couple of taps are open. With wall shower heaters that does not provide a very high shower flow but is usable. We converted to a Grundfos type water cooled jet pump last year which provides 65psi+tank and find that very much to our liking. But I would not recommend if you have doubts about your pipes. We changed to external pipes after leak could not be found (which happened to be in newest addition only a couple of years old).

[Silurian]

Thanks for the responses. I believe you are right and it is rated in watts not hp. I think I was looking at the model number of the pump at the neighbor and it said 250HP. I got that stuck in my head.

So a 250W pump will give me about 17psi on the top floor. I'm still thinking of a 300W pump to get a little more pressure. The price difference between the two isn't that much.

As far as the water system in the house, the connection to this is towards the rear of the townhouse. The tank is located in the front of the house. I also plan to put the pump right next to the tank. So the pipe needs to run from the front of the townhouse to the rear. I guess I worry about leaks and condensation. The Homepro guy says the pipes don't "sweat". I guess they wouldn't since the water that is in the tank would be close to air temperature anyway.

[chownah]

Please note that just because a pump has a bigger motor does not necessarily mean that it will develop more pressure. You should check the pressure and the flow rate for each pump that you consider to determine if they are adequate.

[astral]

The problem with external pipes is that the UV of the sun rots the blue piping after a few years.

[RamdomChances]

The problem with external pipes is that the UV of the sun rots the blue piping after a few years.

Yea but they are soooooo easy to replace or repair. If your out in the "sticks" the biggest worry you have with putting them suspended cielings is mice chewing through them

[lopburi3]

I really don't believe UV is that big a factor when the pipes are well covered with paint. But I haven't made any tests.

[Thetyim]

You must consider water pressure and flow rate.

A 250w pump will not supply enough water for 5 bathrooms.

I would go for a bigger pump.

I used to have a 830w pump suppling my house no problem for the plumbing.

[RamdomChances]

I really don't believe UV is that big a factor when the pipes are well covered with paint. But I haven't made any tests.

Well get out there Lop and get some paint on them. I'll expect a full report in 3-5 years

[GuestHouse]

The data you need is not the wattage, but the delivery pressure (usually given in meters of water but may be in Bar/milli bar or psi)

The delivery pressure should be about twice the height you want to lift the water, so as not to be over straining the pump.

Clearly if it is meters you have no problem working it out.

If in Bars then

1 bar = 10 meters of head

2 bar = 20 meters of head

0.5 bar = 5 meters of head

Milli bar is simply thousanths of a bar

So 500 milli bar = 0.5 bar = 5 meters of head

PSI is aproximately as follows:

15 PSI = 10 meters of head

30 PSI = 20 meters of head

7.5 PSI = 5 meters of head

When choosing the pipe diameter, select the largest practical size for the main runs, The rule is large size, lower pressure drop, small size larger pressure drop.

[lopburi3]

I really don't believe UV is that big a factor when the pipes are well covered with paint. But I haven't made any tests.

Well get out there Lop and get some paint on them. I'll expect a full report in 3-5 years

Have paint on the house runs and most low on walls and out of sun in any case. But have never painted feed to water tanks which are in direct sun and don't know anyone who has; nor have I ever heard of anyone having a problem.

[Butterfly]

For a 3 storey house, you will definitely need a 400W pump, nothing less.

Don't take Hitachi, they are worthless, or the other "Thai" brands

Take the Fujika if you can, actually cheaper than the Mitsubishi (1,000 baht less at 12,000)

Fujika is the Japanse reference that everybody wants. Mitsubishi is not bad though.

Don't compromise with the water pump, they are cheap and prices don't really differ

[lopburi3]

Hitachi happens to be one of the largest engineering and electronic manufactures in the world and is not a Thai brand. It was established in Japan 95 years ago.

1910

Founded by Namihei Odaira as an electrical repair shop

Suceeded in first domestic manufacture of three 5hp (3.6775 kW) electric motors as the company's first products

I have no knowledge of their dependability in Thailand or if they are made here but Hitachi has always stood for high quality products.

[Butterfly]

Hitachi happens to be one of the largest engineering and electronic manufactures in the world and is not a Thai brand. It was established in Japan 95 years ago.

1910

Founded by Namihei Odaira as an electrical repair shop

Suceeded in first domestic manufacture of three 5hp (3.6775 kW) electric motors as the company's first products

I have no knowledge of their dependability in Thailand or if they are made here but Hitachi has always stood for high quality products.

It's a good brand for sure, but not for the pumps

[phuketsiam]

I had an Hitachi one, it was fine

[Silurian]

All the piping would be inside and not exposed to any sun at all. I am not worried about UV rot.

It sounds like the 250W pump is undersized for the townhouse. The price difference between the 300W to 400W pump is about 4000B to 5000B. I need to research the price a little more. I wasn't sure about the Fujika brand. I never heard of it before.

Does it make any sense to put in some sort of filter before the pump to keep dirt from getting in? I saw they have one that goes inline. It was a simple screen in sort of a Y pipe. The guy at Homepro recommended it and that is only comes with certain models. It was easy enough to clean. You just open the Y pipe, take out the screen and clean it. I would think this is good for larger particles.

I plan on putting a water filtration system in the kitchen with UV for drinking water. I'm just not sure about some sort of inline filter for the whole house. If I haven't mentioned this before, we are on Bangkok city water.

[lopburi3]

I don't see any need for a screen before the pump on Bangkok city water - anything in the water should be small enough to not cause any damage to pump and you will have filters on items that might be of concern (washing/dishwasher/showers) so it is just something extra. Your tank should have an outlet on the bottom that you can remove and wash out accumulation of mud.

[Butterfly]

Fujika has a filter, built-in

The consensus from builders and different owners is that Hitachi is trash for pumps and should be avoided at all costs.

[Silurian]

Well, I got the pump installed. But somewhere between the pump and the water distribution line there is a leak so I will need to get a new pipe installed. It will need to pass through the ceiling to the back of the townhouse. I can't really tell if the pressure is good enough since there is a leak. The plumber said the pump might be too small. It is bigger than the neighbor's pump and their pressure is just fine so I have my doubts.

Hopefully next week this plumbing project will be done.

[autonomous_unit]

I'm waking up this older thread because it has lots of related content already... I "reverse engineered" our plumbing to determine why our pump is so ineffective at boosting pressure, and why it was running for too long even when nobody was using water in the house.

It seems the street supply branches to the float-valve inlet of our undeground (atmospheric pressure) tank and also to a sort of "bypass" that heads directly into the house plumbing. In addition to a manual valve, there is an inline device between this street supply and the house which looks to me like an anti-siphon (one way flow) valve.

The booster pump has an input from the tank and output into the house supply line.

I assume the normal operation would be that the street supply valve is open to supply street pressure into the house and also to fill the underground tank. When the street pressure is insufficient, the booster pump will pressurize the house plumbing against the anti-siphon valve. If the booster pump power supply fails, or the street pressure is high, the pump will remain off and the street pressure will supply the water to the house. Is this a correct understanding of a typical/proper installation?

What I am seeing is that I must close the manual valve at the anti-siphon location, at which point the pump provides satisfactory pressure in the house, but there will be no water if the power goes out. The device is not blocking "backwards" flow, and in addition to the pump pressure leaking back out into the underground tank, we actually saw the water meter at the street spin backwards when we let the house pressurize and then opened said valve! I have closed the pump valves and used the street supply alone in the house, so I am sure the anti-siphon is not simply installed backwards. It just doesn't seem to do anything...

Am I right in expecting that all manual valves should remain open, and a properly operating system should automatically supply the house from the street or booster pump? Does it make sense for the anti-siphon to fail within a year or so of installation?

[CGW]

The usual (if there is one?) set up is that after the meter there will be a check valve (one way valve)

This should be on the fill up line to your tank, then your pump should be lined up to your tank to keep the house pressurised.

There are mant variables to this, above is ideal if you have positive pressure to keep your tank full all the time.

I usually arrange plumbing so that flow goes either direct to house(ideal if no electric), or to Tank\pump, not practicle to have it do both.

Thai plumbing is usually done by people who dont have a clue, every house I have had I have had to re-do plumbing.

The fittings used in Thaiald are "Crap" if the check valve has failed after a year don't be surprised, they are less than a 100 Baht to replace.

Cheers

[phuketsiam]

if you have one of those bladder pumps, the pump will only come on if the pressure in the bladder drops enough, so even in the case of no power you can still get water from the street pressure. I suggest removing (closing) the pipe that feeds the house via the street (although replacing the one way valve would have the same effect), if you tank is a pressured one then street pressure will force water thru the tank into the house system, and the pump will come on when required to raise the pressure

[autonomous_unit]

So, it sounds like I have understood what is going on. Well, except for mixing up check valves and anti-siphons.

No, the main storage tank is not pressurized. Only a very small (a gallon or two?) tank underneath the pump is pressurized, so we would only get a few seconds of water flow upstairs before it equalized, in the event of a power failure.

I like the idea of getting the check valve working, rather than expecting everyone to understand and properly reconfigure the valves around the pump. This house is in outer BKK and the street pressure seems sufficient for the ground floor and garden usage. It is the shower water heater upstairs that needs the boost from the pump.

I suppose I should be happy that the builder thought to put in a manual valve next to the check valve, instead of disappointed in the "new" check valve failing....

[Silurian]

My plumber also installed a manual bypass so water from the city can "bypass" the pump. I have it closed off unless the electric stops then it can be opened for ground floor water. I don't have any check valve in the system so the bypass needs to be closed during normal operation.

I'm still waiting on the plumber to do the water through the ceiling. He had a bit of bad luck while riding a motorcycle and was in the hospital for a few days. I would go with another plumber but this guy is pretty good and he already knows what needs to be done. Plus it was implied that he would do the job and I wouldn't consider it fair/polite to go with someone else at this point.

I can't wait to get this plumbing done so I can move on to the next set of projects. I need to redo the cover for the underground tank but I can do that until the outside plumbing is done.

[chownah]

if you have one of those bladder pumps, the pump will only come on if the pressure in the bladder drops enough, so even in the case of no power you can still get water from the street pressure. I suggest removing (closing) the pipe that feeds the house via the street (although replacing the one way valve would have the same effect), if you tank is a pressured one then street pressure will force water thru the tank into the house system, and the pump will come on when required to raise the pressure

If the pump provides enough pressure to supply water to the second floor but the street pressure does not then as long as the pump has electricity then the pressure in the house pipes will be higher than in the street pipes and no water will flow from the street pipes into the house pipes.

Another way to say this is that the lowest pressure in the bladder (the pump turn on pressure) will provide water to the second floor and so it is higher than the street pressure which can not provide water to the second floor.....therefore the street pressure is always less than the house pressure unless the electricity goes out or the pump fails.

[autonomous_unit]

Our house seems to be right on the borderline, pressure wise. I am not even sure it is a lack of static pressure upstairs, but only flow rate when open... There is enough pressure to operate the cold water shower upstairs without the pump, but the flow through the heater is a bit less (it is a very narrow pipe inside the heater) and the heater does not switch on. I assume the heater is flow rate sensitive, rather than static pressure sensitive. The flow rate downstairs does not seem any different at sink faucets with the pump in or out of the circuit, which is why I think the static pressure may be high enough to not always use the pump.

I had several occasions in two years where the power went out in our rented condo while I was in the shower, and the house we're moving to is further out of the city, where I assume the electricity is less reliable. So, I am hesitant to turn off the bypass manually... I don't want to have to run outside to turn a knob if I am mid-shower and the power trips.

[chownah]

Our house seems to be right on the borderline, pressure wise. I am not even sure it is a lack of static pressure upstairs, but only flow rate when open... There is enough pressure to operate the cold water shower upstairs without the pump, but the flow through the heater is a bit less (it is a very narrow pipe inside the heater) and the heater does not switch on. I assume the heater is flow rate sensitive, rather than static pressure sensitive. The flow rate downstairs does not seem any different at sink faucets with the pump in or out of the circuit, which is why I think the static pressure may be high enough to not always use the pump.

I had several occasions in two years where the power went out in our rented condo while I was in the shower, and the house we're moving to is further out of the city, where I assume the electricity is less reliable. So, I am hesitant to turn off the bypass manually... I don't want to have to run outside to turn a knob if I am mid-shower and the power trips.

If the pump consistently provides more water flow than the street pressure alone then the pump does this by consistently keeping a higher pressure in your pipes than the street pressure....it is pressure that makes the water flow and higher flows indicate higher pressure. Sounds to me that when the pump has electricity and is not broken then you are not using any water through the one way valve. I think that the one way valve is supposed to act as an automatic valve that would let you use street pressure delivered water automatically when the pump breaks or the power is out...I think it will do nothing other than that. If you have a manual system to do this then the one way valve is not necessary...if I am understanding correctly how your system works.

Edit: To see for sure how it works you could borrow a pressure gage from someone or buy one and install it. Then by thoughtful planning and experimenting with the pump on or off and the bypass open or closed, you could determine what the pump high and low pressures are and what the street pressure is. Street pressure will vary from time to time. If the street pressure is ALWAYS lower than the low pressure for the pump, then no street pressure powered water is entering your house when the pump is functional. It is possible that at certain times whent the street pressure is higher than the low pressure for your pump that water could flow in your house without the pump working to do it....it all depends on what the pressures are.

Edit number two: A simpler thing would be to run some water somewhere at a very low flow rate and see if the pump comes on or not. If the pump does not come on then the street pressure is higher than the low pump setting....in this situation you would be using the pump as a pressure booster to provide higher flows when necessary.

[phuketsiam]

If I understand the situation correctly, then the simplist thing to do is replace the one-way valve (we know it doesn't work because the pump can make the water meter go backwards). If you have a one way valve in place then under normal conditions the pump will boost the water pressure in to the house, if the power fails then you will have street pressure only. Why not replace the one-way valve and see how that works before you go any further

[astral]

It is rather pointless to pump straight off the mains.

If there is insufficient pressure pumping will not help.

Fill a tank from the mains and pump out of the tank.

A filter on the input to the tank is good idea to get out the large crud.

Most pumps have pressure relief valves so will not burst the pipes.

The higher power means they can push more water and supply more taps

at the same time. Others have advised you on what you need for your building.