Control wiring on heat pump with furnace

[Bcshaw]

Hey I am wiring a heatpump with a furnace as backup. The manual is telling me to wire w1 from t Stat to w1 on furnace then w1 on heat pump.

Would this not kick the furnace on as well?

My thought would be run w1 from t stat directly to heat pump then run w2 or emergency heat to w1 on furnace board. The only problem with this is how would I kick the fan on when running heat pump? Or does G get energized on call for heatpump on t stat?

Thank for any info. I'm I'm Calgary Canada where we do not usually install heat pumps due to cold climate.

[Admin]

Y1 would be your 1st stage heat pump for heating.  It's the same as cooling only with heating it will engage the reversing valve O terminal.  During defrost mode it would use W1 to heat with the furnace.  Same thing when the heat pump cut off engages due to cold outside temps or when you select AUX heating.  You probably want the heat pump to cut off when it's -12C or colder outside, and use the gas furnace only.  It really depends on the heat pump model.

Some manufacturers, like Lennox, want you to install a defrost thermostat at the indoor coil, in series with W1.

What kind of thermostat do you have and how many wires?

[Sergroum]

do you want to tell us the equipment you are setting up?


carrier for example has a whole box for their MARQ stuff

[Bcshaw]

Y1 would be your 1st stage heat pump for heating.  It's the same as cooling only with heating it will engage the reversing valve O terminal.  During defrost mode it would use W1 to heat with the furnace.  Same thing when the heat pump cut off engages due to cold outside temps or when you select AUX heating.  You probably want the heat pump to cut off when it's -12C or colder outside, and use the gas furnace only.  It really depends on the heat pump model.

Some manufacturers, like Lennox, want you to install a defrost thermostat at the indoor coil, in series with W1.

What kind of thermostat do you have and how many wires?

That makes more sense. Haven't picked a thermostat yet but thinking of using a 2 or 3 heat with outdoor sensor. Probably  will use something basic like honeywell t9. Have 8 wires currently and can run more if I have to.

Appreciate the info.

[Bcshaw]

do you want to tell us the equipment you are setting up?


carrier for example has a whole box for their MARQ stuff

It's a 2 stage 96 lennox furnace with a 3 ton ducane (allied) lynx heat pump.

I've installed the heat pump as the canadian government gives us a $4000 rebate and I figured it would be a good opportunity to learn more about them. Our winters are a steady -20 -30 so it will be used more for shoulder season heating.