Thermostat not turning on my furnace for one of my zones

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Old 02-25-13, 07:52 AM
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Thermostat not turning on my furnace for one of my zones

Hello Everyone,

New here and have a quick (I hope) question.

I have an oil furnace. It has 2 zones (3 if you include the hot water heater), first floor is one zone and the second floor is the second. Both zones are controlled by separate t-stats. The furnace seems to work fine for the first floor zone. It cycles properly based on the program temps on the first floor t-stat (either by program or manual override). The problem I am having is that on the second floor, the t-stat does not seem to properly cycle the furnace. When the temp falls below the desired temperature you can hear the t-stat "click" to turn the heat on and "heat on" is shown on the screen, yet the furnace does not turn on. I have tried manually overriding the program as well to make the furnace turn on but that doesn't work either. Nothing happens. I know the furnace is working because it will come on and turn off as it should for the first floor which as I said above is controlled by a separate thermostat. This started happening a couple of weeks ago. I figured it was the battery on the t-stat so I replaced it. That did not solve the problem. I have even since replaced the thermostat to rule out a faulty t-stat and that has not solved the problem. I have resorted to manually opening and locking open the zone value (which seems to be just fine, has good resistance when manually opening and springs back when you let go) so the second floor heat cycles anytime the furnace is on for either the first floor zone or even the hot water heater.

Anybody have an idea what could be happening? Could the low voltage wires that connect the t-stat to the furnace be broken somewhere in the wall? If so how would one trouble shoot and/or repair that? Any other possible solutions? Any help you can give will be much appreciated. Thanks
 
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Old 02-25-13, 02:33 PM
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First of all, you do NOT have a "furnace" you have a boiler. A furnace outputs hot air that is distributed via ductwork throughout the house.

Secondly, when you manually open the zone valve does the boiler fire?

Thirdly, when the second floor thermostat is "calling for heat" does the zone valve open?

If the boiler does NOT fire when the zone valve is manually opened then there is likely a problem with the wiring from the zone valve to to the boiler switching relay. If the thermostat DOES cause the zone valve to open but not fire the boiler then this confirms the problem is in the wiring from the zone valve to the boiler and there is nothing wrong with either the thermostat or the thermostat wiring.

Please post several pictures of your system including boiler from all sides and also the zone valve in question. Include a few pictures from a far enough distance (or wide angle lens setting) so that we can see how the various parts are connected. Please make sure the pictures are well lighted and in focus. Pictures are best uploaded to a photo hosting site such as photobucket.com and the public URLS posted here. Do not try to use tinypic as it is incompatible with this forum.
 
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Old 02-25-13, 03:37 PM
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Manually opening a Honeywell valve will not fire the boiler. It will only open the valve.

I'm not sure about Taco... but I think the same.

My feeling is that you need to replace that valve power head.
 
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Old 02-26-13, 09:47 AM
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Furd & NJ Trooper,

Thanks for the clarification on my boiler.

As far as your questions go, when I open the zone valve manually the boiler does not fire. I have honeywell zone valves. When the second floor is calling for heat the zone valve does not open either.

I will take pictures tonight and update the thread. Any other suggestions? Thanks for the help.
 
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Old 02-26-13, 02:50 PM
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What would probably help is the sequence from the thermostat (beginning point) to the (end point) and the sequence in between of functions. In my system, the thermostat calls for heat. The signal is sent to a board. The board opens the zone valve. The end switch of the first board sends another signal to a secondary board (either priority or TT2) and the isolated switch sends a signal to the Aquastat. The aquastat then opens the vent damper and sends a signal to the electronic ignition, roll out switches and intermittent pilot control and as the pumps turns on first the boiler then ignites (In some sequence). They are all tied in together. I have more than 2 zones so you may only have one board and aquastat, etc. Somewhere the signal is lost. I found this magjumper (look on line) and found this very useful when troubleshooting a system. This way I do not have to run up to the 2nd floor or first floor from the basement. This is a magnetic jumper and you can probably find it at the local plumbing store.

It would be helpful with the sequence of the first floor that is working properly. Pictures are very helpful
 
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Old 02-28-13, 07:19 AM
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I took some pictures and created an album on photo bucket so you can all see what I am dealing with. Hope this helps.

Boiler Pictures Photos by marktrocino | Photobucket
 
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Old 02-28-13, 04:17 PM
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Mark, rotate the barometric damper on your flue pipe so that the 'axle' is level and the face is plumb.

As I mentioned earlier,

My feeling is that you need to replace that valve power head.
40003916-026 - Honeywell 40003916-026 - Replacement Head for V8043E Zone Valves

I can't see clearly in the pics, but before you go taking the head off, make sure that there are only TWO SCREWS and TWO LOCATING PINS holding the head on. If you have FOUR SCREWS, you can NOT remove the head without first draining the system, and you will need a 'conversion kit' to install the new head.

I believe yours are new enough that they will be the 2 screw model.
 
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Old 03-04-13, 02:31 PM
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Thanks NJ Trooper, it was indeed the valve power head. Replaced it and all is good. Thanks for all the help everybody!
 
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Old 03-04-13, 02:40 PM
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Good deal Mark! Thanks for letting us know.

Good Luck!
 
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