Boiler turns on and burns even when room is above the call temp

Reply

  #1  
Old 03-02-11, 07:36 AM
I
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 63
Received 0 Votes on 0 Posts
Boiler turns on and burns even when room is above the call temp

My boiler seems to randomily turn on and burn for a few minutes often during the day. This occurs when the room temperature is above the call temperature setting. The circulator pump does not start, only the boiler lighting and burning for a few minutes.

I will come home from work and see my room is a good 4 or 5 degrees warmer than the call temp and the baseboard is warm(but not hot like when the pump is circulating), so i know its been burning. And the room temp would not have gotten low enough to call for heat, so it's not like the heat was being run and I came home after it stopped and the heat i felt was the residual.

It is a gas boiler, not at home, so i cant recall the make or model, with one zone. Recently had the aquastat replaced, also a new thermostat unit. Im thinking it might be something to do with the low or high setting on the a-stat

Any ideas would be appreciated,
Sorry I can't provide more details off the top of my head.
 

Last edited by InNeedofHeat; 03-02-11 at 07:48 AM. Reason: Addition
Sponsored Links
  #2  
Old 03-02-11, 09:41 AM
D
Member
Join Date: Aug 2009
Location: USA
Posts: 4,947
Received 0 Votes on 0 Posts
It sounds like your boiler is a warm start boiler. That means it maintains the boiler at a set temperture whether or not there is a heat call. The boiler model will help in this identification. If the temperture over run in your rooms is not because of solar gain during the day, there could be another issue in your system allowing ghost flow.
 
  #3  
Old 03-02-11, 10:04 AM
Z
Member
Join Date: Jan 2008
Location: Southeastern Pennsylvania
Posts: 3,148
Received 19 Votes on 19 Posts
hi InNeedof Ė

(droop just beat me. I was going to trash what I wrote below because after I thought more about it I figured it was nonsense, but Iím thinking maybe it isnít so crazy. SoÖ)

Iím am not one of the experts on the forum. (I hang around here in learning mode. )

But Iím wondering if the wrong kind of Aquastat was installed. A Triple Aquastat will turn on the burner to keep the boiler in a minimum temperature range for domestic hot water. So your burner will fire when the boiler temperature falls below a certain setting on the Triple Aquastat - even when there is no call for heat from the thermostat(s).

Thatís the kind of setup I have, and like you describe, the burner will fire seemingly randomly and the circulator will not run. So I think if you donít use the boiler for domestic hot water I donít think a Triple Aquastat should be installed, if indeed that is the case.

I certainly could be all wet. Iím sure the proís will know what you should do.

Good luck!
 
  #4  
Old 03-02-11, 10:22 AM
D
Member
Join Date: Aug 2009
Location: USA
Posts: 4,947
Received 0 Votes on 0 Posts
If your get your domestic hot water through a tankless coil built into your boiler, it will be setup like this. I also believe that older boilers were warm start even if they didn't have that feature. Providing information about the boiler and even the aquastat model number will give some clues as to what is going on.
 
  #5  
Old 03-02-11, 03:44 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Yer all right on... we do need more info... boiler make/model, aquastat make/model, source of domestic hot water in the home.
 
  #6  
Old 03-03-11, 07:10 AM
I
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 63
Received 0 Votes on 0 Posts
Sorry i haven't been around to update for you guys, works been killing me. Anyhow, the boiler is a Peerless - MCB-097-WPC-ID, intermittent Ignition. I do not have the info on the aquastat but im 90% sure its a triple action, it replaced an older aquastat a few months ago. The old aquastat(which looks identical to the new one) is a honeywell - L8148E 1190, i will get the specs on the new one when I get home today. My hot water comes from a hot water tank which heats the water.

If the boiler is a warm start, or the aquastat is causing the periodic start up, is there a neccesity for it even when the room temp is above the call temp?

Im just thinking about the summer as an example, it could get to be 85 degrees in the room, with the heat set at 62, and my boiler could be firing, sounds wasteful.
 
  #7  
Old 03-03-11, 07:32 AM
D
Member
Join Date: Aug 2009
Location: USA
Posts: 4,947
Received 0 Votes on 0 Posts
The water tank you mention is sperate from the boiler? Is this a traditional hot water heater?

With a warm start boiler, it shouldn't be heating your house when it maintains temperature. The pump should be off. If it is continuing to heat your house, then you are having an isse of gravity flow (ghost flow). This happenens when warm water from the boiler rises in the pipes as the cool water falls when the pump is not running. This can be fixed. If you have no need for a warm start boiler, it can be coverted to cold start.
 
  #8  
Old 03-03-11, 07:33 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
The 8148 is a SINGLE aquastat, and would not have been keeping the boiler warm... why on earth someone would replace a single with a triple is beyond my ability to reason.
 
  #9  
Old 03-03-11, 07:38 AM
I
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 63
Received 0 Votes on 0 Posts
The hot water tank is seperate from the boiler, well connected by a copper pipe, but im assuming just for water supply. The hot water heater itself ignites and warms the water used in the house. The boiler does not light when the water tank does.

When the boiler lights periodically, the pump does not turn on, just the burner. The act of heating this water does leave the heat ducts a little warm, but far less than when the heat is called due to a lower room temp, or forced calling at the tstat.

If this is a gravity flow issue, how expensive would it be to fix, or to transition from warm start to cold start?

and thanks everyone, for your help, it's much appreciated.
 
  #10  
Old 03-03-11, 07:41 AM
I
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 63
Received 0 Votes on 0 Posts
NJ Trooper:

I will check the make and model of the aquastat when i get home, but i am pretty sure its a triple. If It was put back to a single would that take care of this issue?

Thanks for your help, much appreciated
 
  #11  
Old 03-03-11, 07:43 AM
D
Member
Join Date: Aug 2009
Location: USA
Posts: 4,947
Received 0 Votes on 0 Posts
According to NJ Trooper (he's wicked smaht about this stuff), your aquastat was replaced with the wrong model. Double check your model number when you get home. The solution seems it will be easy enough to fix by installing the correct aquastat. If you didn't have problems with gravity flow prior to the new aquastat, then you won't need to worry about that after you get the proper one installed.
 
  #12  
Old 03-03-11, 07:46 AM
I
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 63
Received 0 Votes on 0 Posts
Im hoping that is the solution Drooplug. I am pretty sure I did not have the gravity flow issue before the new aquastat was installed. I only lived in the house for about a month and a half before the astat was replaced. But I do not recall any random firings or warm ducts during that time.

Thanks.
 
  #13  
Old 03-03-11, 08:21 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Here's a PDF link for your boiler manual in case you don't have one for it:

http://www.peerlessboilers.com/Deskt...hod=attachment

Is your system just one zone? i.e. one thermostat, no zone valves, etc ?

If they installed the wrong aquastat, I would think that you might still have recourse to have them come back and install the correct one. I know you probably paid like $700 for that, and you paid for a proper job.
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


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