Vision Pro question for Bill W. @ Honeywell........(Starch)

John Starcher_4

I asked my wholesaler for a heat pump thermostat that will control two stages of electric strip heat in addition to the heat pump as first stage. He told me that the Vision stat does 3H/2C, so I ordered one.

I'm looking at the "Typical Hookup" wiring diagrams, and don't see a way to do what I want. I have the comressor as stage one heat, then two banks of strip heaters for stage two and three heat. Initially I considered wiring stage 2 heat relay to the "Y2" terminal in the stat, but I'm concerned that the heat strip will be energized in the cooling mode if the cooling setpoint is too far below the actual room temperature. (This is a single stage heat pump).

Can you give me some advice?

Thanks,

Starch

Glenn Harrison_2

Starch,

If you look on page 19 of the manual, it explains the electric heat operation with heat pump.

In normal operation, Y powers the heat pump, and the aux terminal powers one stage of electric heat. In emergency heat, the E terminal is first stage of electric heat, and the AUX terminal is the second stage of electric heat.

Now the problem becomes how your particular electric furnace operates. If it's wired so that any sequencer will keep the fan running, thern you wire the E terminal to W/W1 in the furnace, and AUX to W2 in the furnace. However, if the fan is only energized by the W/W1 sequencer, then you may have to reconfigure the system for proper operation, or you could just set the thermostat so that it energizes the fan G terminal on any call for heat.

John Mills_3

I was told

by Honeywell customer service that the 3 heat stages meant 2 stage comp and 1 stage of backup. I want to control my 2 stage gas furnace backing a heat pump like you do with electric, I can't see how to do it and was told it couldn't also. Looks like from Bill's explanation, you can stage your emergency heat but not normal heat.

BillW@honeywell

Glenn Harrison...

is right. The only caution I would add, Starch, is to make sure you have the TH8320 model, and not the TH8110. The TH8320 is up to 3 stage heat, 2 stage cool, while the TH8110 is only one stage of each. Go to http://hbctechlit.honeywell.com, and enter form #69-1706 in the appropriate box and print out the complete product sheet. It will give you wiring diagrams and the entire installer setup code list. Make sure you "tell" the stat that the auxiliary heat is electric or fossil fuel. default is electric, setup number is 0200, option 0. If you used a gas fired furnace as a backup, for example, you'd set the parameter to 1. The Installer codes can get a bit tricky if you are using mixed equipment, but just read them carefully, and you should be ok. I hope this is useful, and thanks for using our product.