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1 Temporary workaround while I wait for a replacement Zone Control Board

1 Temporary workaround while I wait for a replacement Zone Control Board

Old 06-10-21, 02:31 PM
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1 Temporary workaround while I wait for a replacement Zone Control Board

I have a two-zone system: Bryant Condensing Gas Furnace and AC with an EWC BMPPlus 3000 Rev B Zone control system with is connected to 2 nest Thermostats and 2 EWC MA-ND5 controls.

We were running the AC on a very hot night and the system shut down in the middle of the night.
In the morning, the nest thermostats we giving a message like “check wiring” and showing the wiring layout of the thermostat. The light on the furnace was flashing rapidly.
I powered off the entire system and checked the furnace 3A fuse. The fuse was blown so I replaced it. When I powered the system back up the furnace light was solid. However, the Fan, Heater, or AC did not come on. I looked at the EWC BMPPlus and there were no LEDs illuminated. I downloaded the manual and went through the troubleshooting section “check you wiring”. There’s 27.5 V AC at the BMPlus Input terminals R and C. I powered off the system and disconnected the R terminals on the thermostat terminal blocks and M2/M4/M6 terminals on the BMPlus damper motor terminal blocks. When I restored power with the disconnected R terminals, the BMPPlus was still unresponsive.
The is a 6/7 year old house and nothing has been changed with the wiring or anything else since we moved in.
I contacted EWC and they said that a "suppose a voltage spike, transient or short circuit occurred to blow the furnace fuse and damaged the BMP incoming power components” They also stated that this "it appears the BMP was powered via the same 24vac transformer in the furnace, rather than a dedicated transformer, as specified in the technical Bulletin”

I’ve ordered a new BMP board but I wanted to ask is there any way I can temporarily turn on at least one zone for Heat/AC until the new board arrives next week. Specifically, how do I connect just one zone thermostat and what do I do about the 2 EWC MA-ND5 controls (the closed LED is on (it’s red) )
Old 06-11-21, 07:27 AM
Join Date: Jul 2009
Location: SE Iowa
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Is there a way to manually operate the zone dampers? If so, make sure they are open. I'm guessing the furnace/air handler doesn't care what tells it to heat/cool/run the fan, so you should be good to run the thermostat directly to it.
Old 06-11-21, 08:28 AM
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There are several things you'd need to do.
You can post a picture or two of your board wiring and we can go from there.

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