Original message
| tangct
 |  "programmable thermostat not working with HRV"
, posted Wed 7 Nov 10:50  
Hi everyone
I have a problem with the Honeywell 7500... would appreciate any suggests/comments...
Replaced the old manual thermostat with the 7500. Wiring was very straight forward. The old thermostat has just 4 wires - R,W,Y,G, so I wired them accordingly on the 7500.
Everything on the heating system is working fine. Tested with Heat set to "on" or "off", with Fan set to "auto" or "on" - everything is OK.
The next day, I turned on my HRV and noticed its not working (blowing) anymore.
Did some quick tests and here's what I found:
- When HRV is off, everything on the heating system works fine.
- When HRV is switched to on, nothing happens. With the HRV on, when I switch the "fan" to on (on the 7500), I hear a click but again, nothing happens.
Called Honeywell but they refused to help me because they don't support HRV.
Please help.
Thanks in advance.
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Replies:
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| Hube
| "Re(1):programmable thermostat not working wit" , posted Fri 9 Nov 10:08
Did the old T stat ever control the operation of the Hrv? (I don't think so.)
But if the answer is yes, then you have not wired the Hrv to the new T stat correctly.
You may also need a fan relay "kit" to operate the Hrv in sequence with the fan (blower) relay.
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| | tangct
| "Re(2):programmable thermostat not working wit" , posted Fri 9 Nov 11:30
The old thermostat never control the operation of the HRV. The HRV has a seperate "OFF - LOW - HIGH" switch.
The strange thing is when I put the old thermostat back, everything works fine.
I'm a newbie in this but the old thermostat only has 4 wires (R,W, Y, G) and I wired them according to the programmable thermostat.
Once the programmable is in place, the heating works fine. However, if the HRV is switch to "LOW" or "HIGH", turning the fan ON does not work on the programmable. I hear a "click" sound but the fan doesn't kick in. If I switch the HRV to "OFF", the fan kicks in.
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| | Houston204
| "Re(3):programmable thermostat not working wit" , posted Fri 9 Nov 18:11:
Post the terminals you connected each wire to and your configuration settings on the Honeywell RTH7500. If it is not operating correctly there is a probability that it is not wired as it should be.
red = ?
green = ?
white = ?
yellow = ?
any jumpers used?
"Tip of the Day" Remember to remove power first.
[this message was edited by Houston204 on Fri 9 Nov 22:08] |
| | tangct
| "Re(4):programmable thermostat not working wit" , posted Sun 11 Nov 21:30
My old thermostat had the following wiring:
Red = RC (which has a jumper wire to RH)
Green = G
White = W
Orange = Y
I connected the wires exactly the same way to the 7500 and I kept the Rc to R jumper that's already in there.
As for setting, I set the "system type - 170" to 4 (Heat only with fan).
As mentioned, the heating works fine. Its the HRV that stops working with the 7500. When I switch the thermostat back to the old one, the HRV works again.
Thanks
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| | Houston204
| "Re(5):programmable thermostat not working wit" , posted Wed 14 Nov 23:07:
The Y terminal is for cooling. Do not connect it to your new stat with option 170 set to 4.
Refer to inner labels
W = white
G = green
Rc & R = red
"Tip of the Day" Remember to remove power first.
[this message was edited by Houston204 on Wed 14 Nov 23:10] |
| | tangct
| "Re(6):programmable thermostat not working wit" , posted Fri 16 Nov 09:43
OK, now I'm confused... why would I have a "Y" wire if its only for cooling? I have just a gas heat furnace and a HRV. Also, if "Y" is not required. why is it connected on my old thermostat?
I will give it a try anyway ...
Thanks
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