Nest Install Help
#1
12-01-18, 07:20 AM
Nest Install Help
I need wiring help connecting a Nest thermostat to a Rudd heat pump outdoor unit Model: UPQL-030JEZ. Current thermostat is Honeywell TH4210D1005. t-stat wiring is E-AUX Jumped, Y, G, O, R, B, C. L is not in use.
According to the Nest compatibility checker my system is not compatible. I suspect it has to do with my unit using separate signals for the changeover valve for heating and cooling. Is there a workaround for this or am I out of luck.
Thank you for reading.
According to the Nest compatibility checker my system is not compatible. I suspect it has to do with my unit using separate signals for the changeover valve for heating and cooling. Is there a workaround for this or am I out of luck.
Thank you for reading.
#2
12-01-18, 07:59 AM
Group Moderator
Welcome to the forums.
Can you post a picture of the thermostat wiring ? ........ How-to-insert-pictures
It's rare to see a wire in both the O and B terminals unless you have an air zoning system.
Can you post a picture of the thermostat wiring ? ........ How-to-insert-pictures
It's rare to see a wire in both the O and B terminals unless you have an air zoning system.
#4
12-01-18, 08:32 AM
Group Moderator
Thanks.
A Rheem/Ruud unit uses the B connection for changeover..... not O.
That Ruud condenser has diagnostics that are sent out on the L wire. I have a feeling your current thermostat was wired incorrectly and the orange wire was on L on the original stat and should not have been used on the current or new thermostat.
The only way to confirm this is to check the wiring connections at the outside condenser and the air handler. You could also temporarily remove the orange wire and see if the system works in heat and cooling modes.
Typical connections shown on page 18 of manual
Ruud manual
A Rheem/Ruud unit uses the B connection for changeover..... not O.
That Ruud condenser has diagnostics that are sent out on the L wire. I have a feeling your current thermostat was wired incorrectly and the orange wire was on L on the original stat and should not have been used on the current or new thermostat.
The only way to confirm this is to check the wiring connections at the outside condenser and the air handler. You could also temporarily remove the orange wire and see if the system works in heat and cooling modes.
Typical connections shown on page 18 of manual
Ruud manual
#6
12-01-18, 10:13 AM
You are correct, I removed the orange wire from the O terminal and both heating and cooling are working correctly.
Thanks for explaining everything so clearly and linking the manual. I installed the new t-stat successfully.
You are a great resource for this community, thanks again.
Justin
Thanks for explaining everything so clearly and linking the manual. I installed the new t-stat successfully.
You are a great resource for this community, thanks again.
Justin
#7
12-01-18, 11:17 AM
Group Moderator
