I am replacing a Robertshaw thermostat which used all 10 wires to a Honeywell thermostat which only has a place for 9 wires.

My system is a 2 state heat pump with electronic filter.

The new thermostat has
Rc R O/B Y G C L E AUX

My old has C L R Y2 Y1 E W2 G O B

What wire do I not use or where do I connect 2 wires?

Thanks
Rhonda

If you used Y1 and Y2 on the old thermostat(two stage compressor) you have the wrong thermostat. W2 and AUX is the same If the old thermostat had a wire on B you will need to set the new one up for reversing valve heating mode If the wire was on O set up for reversing valve cooling mode(new thermostat O/B). You will need a jumper wire from R to RC

Quote:

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Originally Posted by T-Top

If you used Y1 and Y2 on the old thermostat(two stage compressor) you have the wrong thermostat. W2 and AUX is the same If the old thermostat had a wire on B you will need to set the new one up for reversing valve heating mode If the wire was on O set up for reversing valve cooling mode(new thermostat O/B). You will need a jumper wire from R to RC

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Yes Y1 and Y2 were both used on the old one, but this thermostat says it is for a 2 stage heat pump so what do I need? I originally bought a single stage and took it back to get this one.

There was also a wire on both O and B on the old one so do I need reversing valve heating or cooling mode?

The jumper wire is set up from R to RC

Thanks
Rhonda

Here is a link to a wiring reference:
Thermostat wiring code

Post the model numbers or a link to the manuals.

Using O & B as reversing valve connections makes no sense. It might be best to see where these colors terminate at the air handler.

Y1 and Y2 are 1st and second stage cooling.
W1 and W2 are 1st and second stage heating. There is no W1 on your old stat. B COULD be W1. You'll have to check this at the air handler. If this is the case then you need a 2H/2C heat pump t-stat.

1RHONDAJ I'm not sure why you disagree with my answer but if you have a two speed compressor you will need to get a three stage heat two stage cooling heat pump thermostat. Good luck with your project.

I am sorry, I meant to say agree - I could not find out how to change this.