Gas Boiler problem only 1 of 2 thermo works - http://www.hvacmechanic.com/ Forums
Original message
| CraZySteve
 |  "Gas Boiler problem only 1 of 2 thermo works"
, posted Sat 28 Oct 10:24  
Hi All,
I am new to the board and new to the joy (so I hope) of home ownership. I one a 2 floor 1050 sq ft townhouse.
I have a Peerless Gas fired boiler / forced hotwater setup. I have 2 zones each with its own Honeywell MagicStat CT3200 programmable thermo.
Here is the problem. I was vacuuming around the boiler because I had sanded the walls the other day. Now only 1 zone works.
When I moved in both Stats worked fine. After vacuuming now only 1 Stat works... I am pretty good with a Multimeter.
So my initial trouble shooting has been this:
I swapped the stats upstairs to downstairs. Same problem.
So what could be the deal? Did I knock a wire loose?
Thanks in advance!
-Steve
CraZy Steve
-New Homeowner
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Replies:
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| DW1
| "Re(1):Gas Boiler problem only 1 of 2 thermo" , posted Sat 28 Oct 12:02
A standard set up for a 2 zone boiler is to install 2 zone valves and a thermostat to control each valve. Each valve will operate the circulator pump.
Sounds like you may have knocked a wire loose from one of the zone valves. Are there any loose wires dangling around? Look at both zone valves and see if the wiring is the same (caution, it may not be). If not the same check which wires go to which terminals.
If you can't get it going please post the brand of the zone valves and how many wires go to each valve and how they are connected.
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| | CraZySteve
| "Re(2):Gas Boiler problem only 1 of 2 thermo" , posted Sun 29 Oct 21:55:
Hi,
Thanks for replying. Sorry I was away for the weekend.
It does have 2 Zone valves and the wiring is different only in regards to that 1 Thermo controls 1 valve and the other Thermo controls the other. The wiring looks ok to me.
The Zone valves are Taco 571-2's. There are 3 wires going to each Zone valve.
Terminal #1 - Red wire input from Thermo
Terminal #2 - Connected to other Zone valve then to 24VAC Xformer and connected to "T" terminal in junction box on boiler
Terminal #3 - Connected to other Zone valve and to "TV" terminal in junction box on boiler
Also the White wire from Thermo is connected to the other 24VAC Xformer terminal.
Is it possible that the powerhead on the Taco valve went south?
Thanks,
-Steve
CraZy Steve
-New Homeowner
[this message was edited by CraZySteve on Sun 29 Oct 22:30] |
| | DW1
| "Re(3):Gas Boiler problem only 1 of 2 thermo" , posted Mon 30 Oct 09:41
Sounds like a goofy way to wire the system. Generally the red wire from the trans is the power wire sending voltage to the thermostat and the white wire from the stat goes to the valve. Do not change any wires, the system was working...once upon a time.
The red wire coming from the stat to the valve is sending 24v signal to valve to open. Check the voltage on valve not working from R to term 2. When the valve is calling for heat and opens I think it sends a signal from term 3 to the boiler to turn the circulator on.
To verify, turn the no heat stat to 50 degrees, turn working stat to 80. Check voltages at working valve as above. If both valve have the same voltages on a call for heat you probably have a bad power head.
I think the Taco valve has a lever that will open the valve so as a temporary solution you can move the lever and have heat in the no heat zone.
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| | CraZySteve
| "Re(4):Gas Boiler problem only 1 of 2 thermo" , posted Mon 6 Nov 23:15
Hi DWI
Thanks for the help.. I wound up swapping the Power heads and the problem followed the head... so I just need to get another head and I am all set!
Thanks again!
-Steve
CraZy Steve
-New Homeowner
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| | CraZySteve
| "Re(4):Gas Boiler problem only 1 of 2 thermo" , posted Mon 30 Oct 10:17
Ok, I will check that out tonight...
The Taco heads do have a manual override which is how I have been heating the whole place.
CraZy Steve
-New Homeowner
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