Shopping for new hot water heater: The basics??

[Higgins]

No leaks, but my current 17-year-old hot water heater has a flaky boiler that I've spent $500 or so on service calls over the past year. So I'm looking at a replacement, but know practically nothing. I have a 3rd floor condo, where the hot water also feeds my heating system. My current system has a wall-hung, natural gas HydroTherm boiler

and a separate water storage tank, (40 gallon, I think). I'm told this type of unit is unusual and fairly uncommon. It also gets roasting hot in the wide-open storage area where the boiler is located because the boiler is pretty much an open flame.

I don't wanna bug you guys with a lot of stupid questions, but where the hell do I start? Any good web resources that will explain the options to me? Particularly when it comes to brands. Size of the unit isn't an issue, because it's in a wide-open storage area. From what little I know, a tankless unit sounds like it won't have the capacity or convenience that we want.

When I chatted with a service guy once, he suggested that replacing my system could run $2K, which struck me as huge....Thanks.

[PhotoMan]

A hot water heater? If the water's already hot, it shouldn't take a very big boiler. :-)

[Jimmy]

Qualifier: Not a plumber, just another guy who ran into this setup headfirst.

If you have what I think you have... it sucks. They take a heater designed to heat on-demand hot water, then use it to heat the building. Because it can't really do both jobs, they throw on a storage tank and try to keep enough hot water in there to supply your hot water needs. The unit struggles to heat the building. It's not unheard of in apartments but it still sucks. Call the manufacturer of the wall unit and ask them if it's rated to heat a building. Don't be surprised if they laugh.

Exactly. Wrong application, way over stressed.

What he is probably suggesting is replacing your hacked setup with a real boiler for the unit heating. Then you either have that heat your hot water or install a separate hot water heater. The inexpensive way out is to install a separate gas hot water heater for the domestic hot water (under $200 for the unit and maybe a few hundred to install) and let the other unit continue to heat the building. When it dies, you replace that. But, since you are already pumping money into the wall unit, you might want to consider the larger job.

[Marilyn and Bob]

This is not a water heater. It is a boiler for a small hydronic heating system that also provides domestic hot water. $2K is probably not very much for a full replacement including installation. Be prepared to pay more. Unlike a plain water heater, the determination of what the appropriate boiler and the sizing of it is a job for a professional.

[Higgins]

Yes, I was thinking of that myself....And this job is absolutely for a professional, or at the least, it's for someone other than me. But I'm not even quite sure to be asking the professionals. So can I get some elaboration on what "a boiler for a small hydronic heating system" entails and where I might be looking for more information?? I have have now encountered

, which looks promising...

[Des Perado]

If you can get the Hot Water Heating separated from the House Heating, I think you will be miles ahead. A separate standard 40 gallon hot water tank with it's own heating source (electric or gas) is much simpler and far less problem prone than the single systems that supply both hot water and house heating. There have been a few people posting here recently with similar setups to yours and are having problems. If you can separate the two heating systems, I think you will be much happier. Des

[HeatMan]

The recovery rate of the combined system (boiler with an indirect water heater) is usually 2X the recovery rate of a 'standard' water heater.

[Marilyn and Bob]

I think if you read PhotoMan's comments in conjunction with what follows here you will get the big picture. The hydronic heating system I referred to simply means "hot water heat". In a standard hot water heat situation (again refer to PhotoMan's post as to why yours may be a cheap non-standard type) a (well insulated) boiler heats water which is then circulated via a pump through pipes to radiators and/or baseboard heating units. The hot water may also pass through a heat exchanger which heats the water supply to meet your domestic hot water needs. These two systems are usually separate. That is, the radiator water is not connected to the sink water although the heat source is the same.

This is the type of system you want. Or even better, a boiler to supply the hot water to heat your apartment and a separate domestic hot water heater. This is what you should talk to your plumber about. You should be able to get price quotes (at no charge) from several plumbers for this work. Take the combination of the best price with the best confidence you have in the quality of the individual you are dealing with. Also your neighbors may have recommendations.

The original setup you bought into was the cheapest that the developer could do. You now need to upgrade it. Hope this points you in the right direction.

[royroy]

Another thought. My problem was an insufficient quatitity of hot water (teen agers). I installed a sepaprate electric HWH, but used the output of the tankless coil in the boiler as the input to the HWH. That gave me preheated water as long as the boiler was in use for house heat. Help reduce the cost of operating the electric HWH. YMMV

[AJScott]

Teenagers schmeenagers. Doesn't matter if you have several dozen Mexican migrant farm workers living with their extended families in a condo. If you've anticipated their presence and have installed a hot water heater to accommodate their shower needs (that is, if you cared about such things in the first place), there would/should be no "inefficient quantity."

Logic says that three toddlers who all share one bath in the same tub once a week will within a decade grow into three water hogs consuming vast amounts of water and heating fuel once, maybe even twice, a day. Logic says you should buy a bigger heater or freeze when it comes time for you to soap up.

AJS