Replaced tankless heater core, now no heat in zone heaters

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Old 03-25-10, 06:15 AM
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Replaced tankless heater core, now no heat in zone heaters

From another thread, I replaced the heater core for the tankless heater on my Weil Mclain furnace. Now I don't have heat, but the hot water heater works great!!! Living under the warm shower is not a good way to go thru life...

My pressure relief valve is leaking, It has for some time, when I cleaned it out, it didn't help... Home depot didn't have a replacement so I need to go to boiler supply today to get a new valve...

But this does not explain the no heat, the air valve was releasing a lot of steam last night, but I was thinking this was okay since I opened the system when I replaced the tankless heater.

What else could be wrong, I really don't want to run to the boiler supply more than once....
 
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Old 03-25-10, 08:47 AM
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there can be a bunch of things wrong.
First is the relive valve, it should not be leaking as they usually only open above 30 PSI (some are 50).
Look for a water logged air cushion tank (expansion).
Second, unless its a steam boiler, steam should not come out of any part of a hydronic system.

You may have a circulator not correctly re-wired or the aquastat is keeping a domestic call.

We are gonna need way more info to help you than you have given.

Boiler make / model
# of zones if more than one
Some pics of the near boiler pipework..
Etc.
 
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Old 03-25-10, 09:09 AM
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Originally Posted by TOHeating View Post
there can be a bunch of things wrong.
First is the relive valve, it should not be leaking as they usually only open above 30 PSI (some are 50).
Look for a water logged air cushion tank (expansion).
Second, unless its a steam boiler, steam should not come out of any part of a hydronic system.

You may have a circulator not correctly re-wired or the aquastat is keeping a domestic call.

We are gonna need way more info to help you than you have given.

Boiler make / model
# of zones if more than one
Some pics of the near boiler pipework..
Etc.
Okay, thanks for the help. it is a weil Mclain, with 5 zones, I'll take pictures later.. but basically it was a fully functional unit with tankless hot water heater that I replaced the core to the tankless heater yesterday.

Since I didn't disturb any of the circulators, or return stuff, I'll assume they were not the issue. I think my problem is more basic, besides being a novice. Since the over pressure valve was leaking for some time at a dribble, when I replaced the tankless core I tried to clean the valve. I'll replace the valve today.

I'm thinking the pressure tank may be an issue, but I have not removed it at this time. It was last checked in 2001.

I think I have air in the system since the check valves were manually left open. I was able to to drain a couple zones and have heard water going thru the system. I have one zone that has a flair valve, so now I'm trying to understand that valve. It has a spring loaded turn & garden hoe coupling.
 
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Old 03-25-10, 11:32 AM
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kERRY, since you said you left the flo checks open when you drained the boiler it sounds like you drained the whole system and in that case it must be bled. It sounds as if you are just loaded with air from refilling. Until you get the air out the water will not flow through the zones. For future reference there is no need to open flo checks when draining boiler.
 
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Old 03-25-10, 03:16 PM
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It could be your air system failure. Consult a professional plumber to know more about it.
 
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Old 03-25-10, 03:29 PM
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Yeah... what they said... except the part about calling a plumber... since you drained the whole system, you are loaded with air... and replacing the leaking relief valve probably won't stop if from leaking... (unless it is truly defective, and it might be), but it's a good idea to replace them every 5 years or so even if they appear good.

I didn't see where anyone asked... what is the pressure in the boiler both cold and hot? i.e. xxx PSI @ xxx degrees ... that will tell us if you have an expansion tank problem... but here's the thing; with all that air in the system, you shouldn't be having problems with expansion at this point, your whole system is one big expansion tank!

You DID refill the boiler when you were finished, correct?
 
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