Thermostat wiring help - please

[thatguy]

My wife and I purchased a condo that was built in 2001 - it has not been updated in any way since then.. It has a Rheem heat pump w/ aux/emergency heat that has a reversing valve for heat.

The old thermostat was one with the mercury switches so i wanted to replace it with a digital one.. See pic of original wiring below

I bought a Honeywell non-programable thermostat that capable of having both emergency and aux heat

Honeywell RTH516D13 Simple Display Non-Programmable Thermostat | Honeywell Store


I felt confident in switching these out - but sorta confused myself

the old thermostat

light blue to B (reversing valve for heat)
tan to X (auxiliary)
white to E (emergency) with a jumper to W2
green to G
Yellow to Y
Red to R

The new thermostat - i wired
Yellow to Y
green to G
Red to R
Tan to Aux/W2
White to E (emergency)
light blue to O/B

My question is.

1) i was told that Aux and E were basically the same - so does it matter than the W2 was wired in with E before and now its tied into the Aux?

2) Is the light blue correctly going to O/B - (NOTE - i did go into the thermostat settings to make sure this was set to the heat side)

NEW
New
OLD

thanks for the help

Brian

 

[Aquamoose]

Shouldn’t the white wire go to “W” with the shaded background?

 

[thatguy]

Shouldn稚 the white wire go to 展 with the shaded background?

A quick google search said in a ?conventional ? heating system ( non heat pump) the W is used for heat

This is a heat pump and the white wire was originally tied to the E/W2 (emergency heat)

Brian

 

[4get gto]

Without seeing your air handler the "tan" wire or x should be 24v - or common. That wire will now go on C terminal. Others look to be correct. I'd double check inside the unit and see what the tan wire goes first.

 

[thatguy]

I found this post

Changing from a Q674L 1207 to a 6220D thermostat - DoItYourself.com Community Forums

There the tan is also X which seems to be emergency heat.

 

[4get gto]

I found this post

Changing from a Q674L 1207 to a 6220D thermostat - DoItYourself.com Community Forums

There the tan is also X which seems to be emergency heat.

I agree what you're seeing on the picture tan is on x but x is not em. heat. If you look at the lower drawing of the new stat x is actually blue which is neutral or common and goes internally to the two indicator lights. The other side of the lights come the aux heat and em heat.

 

[BrokeFarmerJohn]

Best way to tell if it’s right is go to the furnance, find the board, write down what wire is leaving those terminals and wire your stat up to match. Or rewire both furnance and stat to match this:

Yellow wire to Y Cooling
White wire to W1 Heating (heat pump)
Red wire to R Power
Green wire to G Fan
Orange wire to O/B Reverse Valve
Blue wire to C Common
Tan to W2 Secondary heat (strip heat)

Most likely the old stat didn’t use a common so they used blue as orange. That goes back to my statement of looking at the furnance and see what they did.

Follow the wiring diagram in the book that came with the Tstat. The furnace will have it’s own diagram on the door of the furnance, same with the heat pump.

 

[thatguy]

Without seeing your air handler the "tan" wire or x should be 24v - or common. That wire will now go on C terminal. Others look to be correct. I'd double check inside the unit and see what the tan wire goes first.

I tried to understand the air handler schematic tonight but was totally lost..


OK.. i found the install instructions for the OLD thermostat.. it does seem to X/Tan is the 'common' wire from what it says .. Would you agree?

Can i use a 'meter' to see if it has 24 volts?

So this common wire is only bring power to the thermostat - so that it doesnt run off of the 2AA batteries - is that correct?

thanks

Brian

 

[thatguy]

Ok. We are all good now. X/tan was common and has been put on the C terminal. I also looked closer at the wiring diagram on the air handler and verified Brown was common.

I really had myself confused here and I appreciate the help


Brian

 

[4get gto]

Ok. We are all good now. X/tan was common and has been put on the C terminal. I also looked closer at the wiring diagram on the air handler and verified Brown was common.

I really had myself confused here and I appreciate the help


Brian

Glad it worked out for you Brian.
Many of the older stats can be very confusing. Some need batterys , some work with just one power wire and no common but still have LED read out (power robbing). Some can be so complex they'd make a grown man nuts. Newer ones tend to be more user friendly. Let's not even get into fully the O and B termials....:confused2: