[cyclone27]

Purchased a pair of Honeywell Wifi RTH9580 thermostats. I have a combo gas/heatpump system.

I set up the first thermostat without issue and works fine. However the wiring is a bit different on the 2nd and I am bit unsure.

Old wiring on a ProSelect Thermostat:

red wire =r
orange wire = o
blue wire = c
yellow wire = y1
black wire = w1
green wire = g
white wire = w2

New wiring on the Honeywell

red wire = r
orange wire = w-o/b
blue wire = c
yellow wire = y
green wire = g
black wire = ?
white wire = ?
RC/R Jumper =?

So where do I put the exiting W1 and W2 wires? Read cap w1 or w2 and the remaining wire would go into W2.

RC?R Jumper - do i keep this or remove it?

Thanks,

Ian

 

[cyclone27]

Old wiring for 2nd thermostat!

 

[roughneck]

You have a hybrid heat pump, correct? With gas backup and an outdoor air sensor?

 

[cyclone27]

I'm a novice at this and I am a bit unsure if its a hybrid heat pump or not. I assumed maybe incorrectly that heat was using the gas primarily and heat pump was being used for the AC portion. (flawed logic?) I have no idea about the outdoor air sensor.

Anyway to determine for certain what I am actually dealing with?

 

[roughneck]

It looks like a standard heat pump from the wiring

 

[cyclone27]

Here is the old wiring for the other thermostat I successfully replaced with a new Honeywell.

 

[cyclone27]

Any thoughts on wiring the 2nd Thermostat?

Old W1: black wire = ?
Old W2: white wire = ?
RC/R Jumper =? (Leave as is or remove)

 

[beenthere]

Any thoughts on wiring the 2nd Thermostat?

Old W1: black wire = ?
Old W2: white wire = ?
RC/R Jumper =? (Leave as is or remove)

Both black and white to W2. Leave the R to RC jumper in place.

 

[cyclone27]

The old W1 and old W2 into the new W2. Any issue combining the two like this? (Enough room)

 

[beenthere]

The old W1 and old W2 into the new W2. Any issue combining the two like this? (Enough room)

Should be enough room.

Draw back is you no longer have stage aux heat, like you did on the old stat.

 

[cyclone27]

No Stage Aux heat, can you elaborate?

Btw thanks for your replies!

 

[cyclone27]

Can anyone explain what losing staged aux heat means? (Pros vs Cons)

 

[supers05]

You'll have shorter run times, but slightly less comfort. It's what most people have anyways. Staged aux is a premium feature that isn't common in most houses.

I doubt that you'll notice the difference. If you do, and want what to have now, then you need a stat that has 3 stages of heat instead of 2.

Cheers!

 

[user_12345a]

You should get a thermostat that stages the aux heat.

You don't need the entire heat kit coming on (yah yah, i know the sequencer have a short delay) for defrosts and supplemental heat.

With W1 and W2 jumped anywhere in the system the entire set of heat strips will come on when it goes into defrost when all you need is a light tempering of the supply air so u don't get a cold blast.

It's cheap to stage the aux heat, it's only a premium feature in resi because resi is held to a low standard. People don't care.

 

[beenthere]

No Stage Aux heat, can you elaborate?

Btw thanks for your replies!

If your aux heat is 2-5KW heaters. It will bring on both heaters, so that you are using 10KW of aux heat, when you may only need 2KW. It shortens the heat pump run time, and can raise your heating bill slightly.

 

[roughneck]

Just be careful using a programmable thermostat with a heat pump. If you have setback times in the schedule you'll often drive your energy use up, resulting in higher electric bills. The fix for this is to use a thermostat with aux heat lockout, and an outdoor air sensor, which I don't believe your thermostat is capable of.
Otherwise your unit will be most efficient just setting it and leaving the set point alone.

 

[user_12345a]

not only that, but if u set it back during the day when at work, you'll prevent the heatpump from running when it's most efficient.

programmable t-stat is great for straight electric/gas/oil forced air furnaces. AC only if there are time of use rates involved.

Otherwise the best setting is hold. The capacity isn't there.