Zones Overheating


  #1  
Old 10-15-14, 04:34 PM
D
Member
Thread Starter
Join Date: Feb 2000
Location: Pa
Posts: 163
Received 0 Votes on 0 Posts
Zones Overheating

National Boiler
Taco, SR 503 Control Panel
3 Zones
2 Programmable Thermostats, I regular thermostat


I'm having a problem with overheating in the 2 zones with the programmable thermostats. The thermostats are set anywhere from 59 to 68 degrees but the room temp is always 70 - 72 degrees. That temp persists 24 hrs a day, irregardless of the thermostat program. I have checked the programs and they are ok. I have replaced one thermostat and the problem persisted. The non-programmable thermostat zone is working ok. But this zone isn't calling for heat.

I'm clueless as to what is causing this. My wild guess is there is a problem with the Taco controller. Do you have any ideas for me?


Thanks,

Denny
 
  #2  
Old 10-15-14, 04:52 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 4 Votes on 3 Posts
Hi Denny,

You may have what is sometimes called 'ghost flow', or 'gravity flow', or 'thermosiphon'.

If you can take and post pictures of the boiler and the piping around it we may be able to spot something easier than asking a million questions...
 
  #3  
Old 10-16-14, 12:35 PM
D
Member
Thread Starter
Join Date: Feb 2000
Location: Pa
Posts: 163
Received 0 Votes on 0 Posts
I tried to upload a picture but it failed. I'm not sure that it's necessary. The system worked fine for 10 yrs and then started to malfunction at the end of last heating season. There were no changes or work done on the system to account for it.
 
  #4  
Old 10-16-14, 12:47 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 4 Votes on 3 Posts
Do you know if there are flow check valves on each of the zones?

By asking for pictures, I was hoping to be able to SEE if there are.

You might have one that's stuck open.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: