Heating, Air Conditioning, Fridge, HVAC/Furnace zone not working


Controller:  Honeywell Universal mini-zone (EMM-3U I believe)

Thermostat set to heat.  Heat LED comes on and zone LED comes on, furnace starts but zone valve does not open.  zone valve is wired ad a "power closed/spring open" valve (i.e. to pin M1 and M6 on the controller)

Zone 2 works, zone 1 does not work

I have multimeter but don't know what to check for on the controller to see if the issue is the controller or the valve itself.

Also, controller has 3 zones, one of which is unused.  If the controller is bad what is to stop me from switching Zone 1 to Zone 3?  Does Zone1 have to be connected?

I don't know your zone valves, I have no lititure?
With a residentil type zone valve, 24 volt, the thermostat when it clls for heat closes sending 24 volts to the zone vlve motor, when the zone valve gets open it closes a switch tht sends 24 volts to the heating unit.

Heating, Air Conditioning, Fridge, HVAC

All Answers

Answers by Expert:

Ask Experts


Jim Barnhart


Fifty + years conditioning the air.


Answer questions about , residential and commercial. Answer questions about sheet metal fabrication. Fifty years plus experience. No answers for oil equipment, No answers for kitchen appliances, No answers for laundry appliances, I don't specialize in one particular area of the HVAC area, I'm more of a General Practitioner, Limited in refrigeration/

Hands on since 1950

©2017 About.com. All rights reserved.