Gas Water Heater And Hot Water Piping

[Mike45]

I've given up on the idea of a gas heater for the whole house. I'm afraid to buy the Mazuma 7L only to find out later its undersized and we don't have enough hot water.

It also seems to be a big problem to run hot water pipes throughout the house. PPV-R with quick connect fitting have bad reviews on the Internet. Welding the PPV- R pipes seems to be the way to go and probably the shorter the better.

So I've decided on the electric multi point Stibel Eltron. There is a 6000W and an 8000W models. I want to put one on the second floor servicing two bathrooms and the second on the first floor servicing the kitchen and bathroom. All bathrooms have showers.

Does anyone have any advice on which model to choose or on the hot water piping?

Thanks

Mike

[Langsuan Man]

Bad idea to try and have one unit service each floor. (since you are turned off by plumbing hot lines) How is the person using the shower going to lower or raise the water temperature if the control is on the unit, that may not be where they are located. And NO, using the cold water intake to control the water temperature will not work since the sensor in the unit is designed to increase the water temperature that is flowing through it. not what is coming out at another location

If you want to do two bathrooms per floor then you would be better off purchasing a tank system such as the Fagor line

[Mike45]

Perhaps I don't understand your concept.

Your saying that when one of these multipoint heaters are used they are only designed to supply water to one location and its meant to have the water adjusted manually by reaching and adjusting it on the heater itself?

I had envisioned that the purpose of the multipoint heater was to be a source of hot water and supply a flow of hot water that is preset to a certain temperature. That water is transported to a mixer valve at the sink and shower that allows you to adjust the temperature lower by mixing in some cold water that is also presented at the mixer valve by a separate cold water pipe.

[Langsuan Man]

Look at the picture you posted. What is that knob in the center of the unit ?

Multipoint heater means multipoint in the same location, whether it be a shower and sink or just shower. In most cases when you use these types of heating units you use them to save on plumbing costs since you only need one water line

If you really want to do it, using these types of units, then get the Stiebel DHM6, which has a fixed temperature and is designed to use cold water at the tap to control the amount of hot water (around 6,000 THB) not a control knob on the unit

Edited February 26, 2013 by Langsuan Man

[Naam]

Perhaps I don't understand your concept.

Your saying that when one of these multipoint heaters are used they are only designed to supply water to one location and its meant to have the water adjusted manually by reaching and adjusting it on the heater itself?

I had envisioned that the purpose of the multipoint heater was to be a source of hot water and supply a flow of hot water that is preset to a certain temperature. That water is transported to a mixer valve at the sink and shower that allows you to adjust the temperature lower by mixing in some cold water that is also presented at the mixer valve by a separate cold water pipe.

you can use a multipoint heater the same way like a single unit. but you need of course cold and hot water line at the point where you mix and draw water at a specific desired temperature. using single units for each bathroom would be my preference although the initial cost is slightly higher.

[Gary A]

You'll save yourself a lot of grief by using separate heaters wherever needed. The plumbing and mixing valves will be added expense besides being a headache.

[Khonwan]

I have a 12,000W (400V) multi-point unit in my shower room. I also plumbed it into my kids’ room through the wall. Both outlets have mixer taps with ‘cold’ (unheated) water. It is useless when two showers are being taken at the same time. I now intend to fit the kids’ room with its own unit.

[luudee]

Mike,

I just threw out my brand new Toshiba 8KW "multi-point" heater as it was a piece of crap ...

After 4 months, some internal sensor rusted out and it stopped working. I still have it if

you want to come and pick it up and fix it ...

I have a similar setup, where it was feeding a bathroom and kitchen, and another unit

is feeding another two bathrooms. It would never provide enough hot water at a decent

rate. Trying to fill the kitchen sink with really hot water was impossible, and took half

an hour ...

I found a real 50L heater with tank, AND sacrificial anode and Home Works ! The only

reason I had the "instant" 8KW heater was because I couldn't find the hot water tanks

with sacrificial anodes,a nd they wopuld rust through after 3 years. Now that I found

one (I also ordered some spare anodes) I am very happy.

I use the regular blue plastic PVC pipes. You have to be careful and not run the hot

water tank to hot, they will expand, I have some very funny "pipes" ... but they seem

to be holding up, even the joints are good ...

Good luck !

luudee

[Mike45]

You'll save yourself a lot of grief by using separate heaters wherever needed. The plumbing and mixing valves will be added expense besides being a headache.

Gary one of the things I'm trying to accomplish is getting hot water to my sinks. I can't think of any other way of doing it.

[klikster]

Lucky Flame imports Rinnai gas demand heaters, 26 & 32 l/m from Bt 35k to 50K

http://www.luckyflame.co.th/products/electric-shower.html

[Mike45]

Lucky Flame imports Rinnai gas demand heaters, 26 & 32 l/m from Bt 35k to 50Khttp://www.luckyflame.co.th/products/electric-shower.html

I went to Ubon Gas in Ubon Ratchathani. They called Lucky Flame and were told that they don't have them for sale any longer. I can see from your link on their web page that they show some products. How recent is your information?

[klikster]

Lucky Flame imports Rinnai gas demand heaters, 26 & 32 l/m from Bt 35k to 50Khttp://www.luckyflame.co.th/products/electric-shower.html

I went to Ubon Gas in Ubon Ratchathani. They called Lucky Flame and were told that they don't have them for sale any longer. I can see from your link on their web page that they show some products. How recent is your information?

Wife called Lucky Flame in BKK about 1-2 months ago and they told her they had them in stock.

Also, I believe the Rheem dealer in BKK has tank style gas heaters .. actually, not a bad way to go by putting the heater in a "closet" adjacent to the house with the flue outside.

Edited March 11, 2013 by klikster

[Khun Jean]

If your location allows it, solar heat can be a good option.

You would then heat a stored amount of oil which then heats water on demand through a heat exchanger.

Or you could use a boiler type that stores heated water.

You would then only need a electrical heater when it is not sufficient in volume or temperature.

Initial costs are higher. Solar heat is a lot cheaper then solar photo voltaic for electricity.

[klikster]

If your location allows it, solar heat can be a good option.

You would then heat a stored amount of oil which then heats water on demand through a heat exchanger.

Or you could use a boiler type that stores heated water.

You would then only need a electrical heater when it is not sufficient in volume or temperature.

Initial costs are higher. Solar heat is a lot cheaper then solar photo voltaic for electricity.

I'm thinking very seriously about solar heating since my future carport has a southerly exposure.

Many moons ago I acted as the "mechanical and fabrication guy" for a buddy (heat transfer specialist then working at Fluor Corp) designing solar panels for his own house.

The transparent/translucent cover is apparently very important in making sure the best wavelengths of light get to the surface of the exchanger. I believe he used Lexan (GE), which is a polycarbonate .. but I'm not sure if all transparent polycarbonates are equal. For sure, not all transparent materials are equal.

Also, tubes or plates in open air lose a lot of heat to both natural and forced convection. I may go with plate style exchangers since tube types lose a lot of "area" benefit if reflector type concentrators are not used.

But I'm not willing to fiddle with oil for any number of reasons. Basically, the main benefit of oil as a transfer media is that it has a much higher boiling point than water. Heat transfer rate of water is much better than oil.

I doubt any single method is efficient enough going from line to storage to shower. But storing 50 or 60 degree C. water is not all that difficult, and running that through even a small gas heater can boost the effective rating significantly.

As far as photo-voltaic, okay (for me) for smaller direct electric devices like yard lights, etc .. but nothing heavy duty.