on demand water heaters

[dug]

Still undecided on how to heat the water and where to put it and have a couple more questions.

A friend who just installed a tankless told me yesterday that in order to connect a solar system with an on demand heater I need to get one that is thermostatically controlled to recognize incoming water temp. Actually I'm not sure if that is exactly right as I only talked to him a minute but it was something like that. He said most on demand heaters were not like this. Anyone know any specifics on tankless heaters and solar setups?


Also still considering a tank heater. It can get pretty hot here in the summer and I was wondering if a tank heater would add significant heat inside the house. A good thing in winter I realize but our summers are long and I am hoping to avoid mechanical cooling , though I will install an evaporative cooler if that doesn't work out.

[hpinson]

Does anyone know if these clog up in areas of mineralized water.  I have such water, and calcium carbonate scale forms really quickly in my home swamp cooler, and probably inside of my hot water heater tank.

[MountainDon]

dug, your friend is right. Some on demand are not approved for preheated water. Don't know what that means but I checked the manual a Bosch.

Re the summer winter use. Our high end 2 inch foam insulated storage tank does not even feel warm to the touch. The pilot light models give off some heat, not much, although when the burner is one there is waste heat from the exhaust. WOSmith and others also make blower driven water heaters up to 90% efficient. Very little heat into the building. The use electronic ignition too, no pilots.  It's in a storage closet with an air intake from the outside.

hpinson, yes mineral content of the water can be an issue. Some manufacturers specifically void their warranty when used with water that is too hard. Water has to be conditioned first.

[glenn kangiser]

Does anyone know if these clog up in areas of mineralized water.  I have such water, and calcium carbonate scale forms really quickly in my home swamp cooler, and probably inside of my hot water heater tank.

I also read that you want to set your tankless heater to only the hottest water you need - not excessively hot then cooling it with cold, as the hotter the water gets, the more chance you have of precipitating the minerals out.  Better to use all hot water from the heater if needed than to overheat it and mix cold with it, for the sake of heater life. 

If not treating the water that is what I would do.  We have a bit of mineral in our water and no problem with the heater doing it this way - I would guess about 8 years on this heater - not exactly sure.

[davidj]

Our plan is to install the remote control for the Takagi which allows you to sent the temperature. I think it's something like $130.  We're gonna put it near the shower so you can just run all-hot water and set it to whatever temperature you want.