I purchased a Honeywell Vision 5-1-1 Day programmable thermostat to replace a Lennox thermostat (51H4301). This is an all electric heat pump type unit (Lennox HP 21-511-5P). According to the Honeywell manual, if the old thermostat has wires W1, Y1 and W2, some system modification is required. Call your local heating and cooling contractor for assistance. My old thermostat does have W1 and Y1 (not W2). It also has a Y2 which is not mentioned in the directions for the heat pump style (Y2 is in the conventional details). Is this wiring something someone could help me with or should I do as the manual states and get a heating and cooling contractor?
Thanks
Troy

We have some good people here, but so far we are a little weak in HVAC. W1 and W2 are for 2 stage heating, and Y1 and Y2 are for 2 stage cooling. The question is not what the old thermostat had, but what the heat pump needs. The old thermostat may have had 2 stage functionality that wasn't used. The heat pump may also be capable of choosing stages. I have a 2 stage furnace, but it, not my thermostat chooses which stage. If you can figure out what the heat pump needs, you don't need a heating contractor. Usually they have a basic wiring diagram on them. You may even have been left a manual or installation guide somewhere on the unit. The manufacturer's website may have the info you need. It may be as simple as connecting the Y1 and W of the thermostat to the Y and W of the heat pump.