New Thermostat now no Zone 2 heat

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jamesr
Posts: 1
Joined: Sun Dec 11, 2011 4:54 pm

New Thermostat now no Zone 2 heat

Post by jamesr »

I have a EWC-ST-2D Ultra Zone Controller that originally had mercury thermostats. I replaced both Thermostats with RTH2300 series (Home Depot). In the thermostat instructions, they state if you have an orange and blue wire, then connect the O-wire and leave the B-wire open.

Since the installation, I no longer have heat to Zone 2 however the AC works in Zone 2 in the summer. I download from this website the tech manual. I measured the voltage between C-W, C-Y,C-R for Zone 2 on the control and there is no voltage.

I am not sure if this is caused by the Honeywell RTH2300 series thermostat due to a B-wire that is open? or if Zone 2 is fried on EWC-ST-2D and how I can confirm that. And what I need to do next. Thanks.
Pcyrana

Re: New Thermostat now no Zone 2 heat

Post by Pcyrana »

Unfortunately that RTH2300 thermostat will not work for you on Zone One.
Your Zone One thermostat needs to have a separate O and separate B terminal.
If you want a simple non-programmable thermostat you can use the Honeywell TH3110D.
Both the O and B terminals need to be wired to the board separately.
trobros
Posts: 2
Joined: Wed Dec 01, 2021 4:52 pm

Re: New Thermostat now no Zone 2 heat

Post by trobros »

Dear Pcyrana,

I recently purchased an RTH2300 thermostat as a replacement for my zone 1 thermostat. I have an EWC ST 2C control planel. The thermostat has seperate O and B terminals as seen in the attache photo. Do you see any reason this wouldn't work with my panel?
Steven W.
Posts: 46
Joined: Tue Jun 25, 2019 9:13 am

Re: New Thermostat now no Zone 2 heat

Post by Steven W. »

Sorry but Patrick cyrana does not work for us anymore.

But yes that stat should work.
Steven R. Weisneck
Technical Engineer
Tel: (732) 446-3110 Ext. #461
www.ewccontrols.com
sweisneck@ewccontrols.com
trobros
Posts: 2
Joined: Wed Dec 01, 2021 4:52 pm

Re: New Thermostat now no Zone 2 heat

Post by trobros »

Thank you Steven!
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