Combination boiler/water heater?

Old 10-26-08, 08:06 AM
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Combination boiler/water heater?


I currently have an early 70's Wiel-Mclain 4 zone natural gas fired boiler. Two of the zones are for my basement radiant floor heating which are almost never used.

I noticed that my water heater is leaking from the top, so I am interested in replacing both at the same time. I have been doing some reading, but am not sure what is the best solution might be for me. At first I was thinking of just replacing the water heater with a tankless heater, but then thought of including the boiler in the mix.

I like the idea of an indirect system but during the summer it might not be so efficient. I live in the Chicago area so our heating sesaon is pretty long but not year round. Is it possible to put a tankless water heater after the indirect water heater system for use when the boiler is not needed? I was also thinking that if I combine the water heater and boiler, what if one of the systems breaks?

These are just a thoughts I had, but I'm just a handy guy not a professional, I am open to suggestions from people who know way more than me here. Let me know if there is more information that you might need as well.

Beer 4U2
Old 10-26-08, 02:07 PM
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Replace the boiler and install an indirect water heater. It will make efficienct hot water all winter and you will lose some efficiency in the summer but will still be a good way of making hot water all year round.
I would not install a tankless after the indirect. Too much money and overkill to use both. Choose one or the other. The indirect with an efficienct boiler will be your beat application.
You can use a high effciiency cast iron or modulating/condensing boiler. The operation cost between the two is not that great. The mod/con will be most efficienct whrn the radiant runs but you said it does not run very much.
The greatest savings is proper boiler sizing and near boiler piping, correct flow and outdoor reset (for heating).

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