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Honeywell T8775A 1009 - not working
Jshine
Member Posts: 19
Post transferred from "The Wall"
I have a gas boiler/steam heat system. The current thermostat is a t87f (2 wire - 1 connected to pressure control - 1 connected to low water cut off) - and works ok but we thought we'd install a new digital display to make it easier for us to read. I bought a Honeywell T8775A 1009 - installed the only 2 wires that were connected to the T87F to the only 2 terminals R and W on the digital - but it didn't work. The display would repeatedly light up after a few seconds (but not when you depressed the button to manually backlight) and then display blank - the little burner flame indicator came on ok - but down at the gas furnace - I noticed the damper was continuously cycling. The damper was actually slowly turning a full 360 degrees and the electronic ignition never kicked in to start the furnace. I tried changing the dip switches back to off and tried reversing the 2 wires - no good - still the same results - no ignition and the damper kept revolving. I called the Honeywell help line - described the situation - and they said it was a bad thermostat. I have a replacement coming - but I'm thinking there might be more to it - maybe a need for one of those "isolation relay" setups that I read about. Maybe not. Anyone have any ideas on this?
Thanks - John
Thermostat - <a href="http://yourhome.honeywell.com/home/Products/Thermostats/Digital-Non-Programmable/Digital+Round.htm">http://yourhome.honeywell.com/home/Products/Thermostats/Digital-Non-Programmable/Digital+Round.htm</a>
I have a gas boiler/steam heat system. The current thermostat is a t87f (2 wire - 1 connected to pressure control - 1 connected to low water cut off) - and works ok but we thought we'd install a new digital display to make it easier for us to read. I bought a Honeywell T8775A 1009 - installed the only 2 wires that were connected to the T87F to the only 2 terminals R and W on the digital - but it didn't work. The display would repeatedly light up after a few seconds (but not when you depressed the button to manually backlight) and then display blank - the little burner flame indicator came on ok - but down at the gas furnace - I noticed the damper was continuously cycling. The damper was actually slowly turning a full 360 degrees and the electronic ignition never kicked in to start the furnace. I tried changing the dip switches back to off and tried reversing the 2 wires - no good - still the same results - no ignition and the damper kept revolving. I called the Honeywell help line - described the situation - and they said it was a bad thermostat. I have a replacement coming - but I'm thinking there might be more to it - maybe a need for one of those "isolation relay" setups that I read about. Maybe not. Anyone have any ideas on this?
Thanks - John
Thermostat - <a href="http://yourhome.honeywell.com/home/Products/Thermostats/Digital-Non-Programmable/Digital+Round.htm">http://yourhome.honeywell.com/home/Products/Thermostats/Digital-Non-Programmable/Digital+Round.htm</a>
0
Comments
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Control problem
Hi John-
I tried logging on to the Honeywell site to see if there was something unusual about the setup of your stat, but I kept getting knocked out. You mentioned that the damper keeps turning on a call for heat-are you talking about the flue damper? If so, it could be that the proving switch isn't making. The problem might be with the damper-not the stat. Check to see if you can lock the damper in the "test" or "service" mode, and see if the system will fire.
A sure fire way to see if the stat is at fault is to remove it, and jump out R-W. If your system works fine that way, the problem is with the stat. If it still acts up, the problem is elsewhere.
All the best!0 -
Honeywell t8775a
Will - thanks for the reply -
I actually put the old t87f thermostat back in place and everything worked ok as before - and yes - it is the flue damper that I was talking about.
I guess I'll just try the new replacement and see if it works.
John0
This discussion has been closed.
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