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BillyHvac
BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22514
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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Got a problem with a Honeywell EMM 3 controller. Thermostats

Customer Question

Got a problem with a Honeywell EMM 3 controller. Thermostats call for heat, the fan turns on, the EMM3 has a red light but I don't get any voltage going to the furnace to call for heat.
Submitted: 1 year ago.
Category: HVAC
Customer: replied 1 year ago.
Sometimes the system light will flash orange and all 3 zone lights will flash green. I only use 2 zones.
Expert:  BillyHvac replied 1 year ago.

hello,

the zone control will connect a relay to furnace when calling...it uses the furnace power and not the zone power.

At the equipment terminals...if you have 24v at R and C.....and then at thermostat terminals (in zone panel) you vac 24v at W and C...and furnace does not work.....then you have a bad panel.

Customer: replied 1 year ago.
Replaced the panel with a Honeywell hz322 but still having problems with the heat call. Fan works fine but the heat does not turn on when the heat light turns red on the hz322. If I jumper the fan and heat wires together right at the furnace then the heat turns on.
Expert:  BillyHvac replied 1 year ago.

do you have any extra wires in the cable?

And did you have 24 volts at C and W?

Customer: replied 1 year ago.
No voltage between C and W. I have red wire to Rh which is jumped to Rc, white to W, and green to G. With the fan running I don't get voltage between G and W either.
Expert:  BillyHvac replied 1 year ago.

ok...

at the zone panel with a call for heat..

at the equipment terminals. Measure C to W.

THEN if 24v is at zone panel C to W.....tell me if there is 24v at ffurnace circuit board C to W

Customer: replied 1 year ago.
Alright, with a call for heat the heat light turns red, the fan light turns green and the fan turns on. I don't get any voltage between W1/E or W2 (equipment) and C (power).
Expert:  BillyHvac replied 1 year ago.

Well, lets start at hot wire.....when light is lit....is there 24v R to C on equipment terminals in zone panel

Customer: replied 1 year ago.
Yep, 24v at R and C at the power terminals.
Expert:  BillyHvac replied 1 year ago.

ok lets clarify...there are termials R and C for power to the board...this runs the thermostats.

Then we have 24v delivered by the equipment..but this is at the equipment terminals (wires from furnace)

Which R terminal are you reading the 24v on?

Customer: replied 1 year ago.
I measured that at the power terminals. For the equipment terminals my options are RH, RC, W1/E, W2, Y1, Y2, G, O, B DS/ BK.
Expert:  BillyHvac replied 1 year ago.

if you take a paper clip shaped in a U.....and at equipment terminals you hold one end on R and other on W...does exhaust fan start in furnace?

Customer: replied 1 year ago.
It does not but I hear what sounds like a relay clicking inside the electric duct heater. This is setup to run gas primarily with electric as a dual fuel option. The electric duct heater is wired between the hz322 and the main gas furnace.
Expert:  BillyHvac replied 1 year ago.

so gas is first stage with electric duct heater as second stage or emergency?

And does r to w2 start gas furnace?

Customer: replied 1 year ago.
the main power for the electric heaters is always off so it only has the 24v going to it. The switch on the front is set to oil/gas instead of dual energy. I notice that the light next to oil/gas lights up when the hz322 calls for heat. R to W2 did not start the furnace.
Expert:  BillyHvac replied 1 year ago.

ok , if the issue remained after replacing panel we have a breach in the gas wire...we know the R is Good and electric heat wire...r to g should start fan/blower.

we need to trace the thermostat wire that goes to W terminal in gas furnace and see if a bad wire nut, optional safety etc is between the furnace and zone panel

Customer: replied 1 year ago.
I traced the wire as far as I could to and through the electric duct heater (Thermolec T-20U-DFC with a TH400 board). I don't see any physical breaks or loose wires.

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