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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Billy, As we had discussed I have purchased a HZ221 True

Customer Question

Hi Billy,
As we had discussed I have purchased a HZ221 True zone panel.
I was trying to match up the wires on my Trol a temp mm2 with HZ221 and did not find a match on HZ221 for a white wire from my old panel for the equipment section. See the attached picture regarding my current installation.
Submitted: 12 months ago.
Category: HVAC
Customer: replied 12 months ago.
See the manual for HZ 221 for a quick reference.
Expert:  BillyHvac replied 12 months ago.

as that the only wire in question? or is the white from thermostat also open?

Customer: replied 12 months ago.
Thats the only wire in question. I wad able to map the others.
This wire is not from the thermostat but going to the equipment section.
Expert:  BillyHvac replied 12 months ago.


Regarding to "fan only" function.

Do you ever use fan on....or do you leave in auto?

Customer: replied 12 months ago.
We leave it at Auto
Expert:  BillyHvac replied 12 months ago.

put the white on equipment to O

Put white at thermostat to O

Customer: replied 12 months ago.
Thanks will try it out and reach out if there are any issues.
Expert:  BillyHvac replied 12 months ago.

just keep me posted with any issues

If O is reverse operation put on B.

Customer: replied 11 months ago.
Hi Billy,
As I was wiring the panel as we had discussed, I am not sure where the wiring for K2 on Trol a temp mm2 (old) goes on the HZ221. The wires in question are brown (O1), green (G1) and blue (B1).
Expert:  BillyHvac replied 11 months ago.

with the new panel you do not need a master /slave thermostat set up.

Strip back thermostat wire cover at slave stat and at board. Put red to r, yellow to y green to g etc. Put white on W at thermostat and on B in zone control..

Do this on both thermostats.

At equipment terminals....put the white wire on B

Customer: replied 11 months ago.
I have done that.
On the old pannel there were 4 slots K1 thru K4.
I have matched K1to equipment, K3 and K4 to Zone 1 and Zone 2 respectively.In the panel thermostat section for zone 1 and zone 2 put white wire in O as there is no B.
The wires from K2 slot brown (O1), green (G1) and blue (B1) which section on the panel do they have to go. Equipment or Thermostat for Zone 1?
Expert:  BillyHvac replied 11 months ago.

those are not needed as that was what determined master and slave.

Now we have direct input by both.

The o and b just gave the master thermostat power after it was done.

Customer: replied 11 months ago.
O and B are power and G is the fan right?
If they are not needed should I disconnect them at the thermostat or just tape all three of them off at the panel?
Expert:  BillyHvac replied 11 months ago.

Just tape the 3 off at panel.

Customer: replied 11 months ago.
I have setup it up as discussed and turned it on. The Zone1 and Zone 2 lights are green and purge light in yellow blinking. I can hear a humming sound . If I press the Emergency Heat the fan kicks on. But cool in not getting turned on.
Customer: replied 11 months ago.
Any thoughts on what might be wrong?