HVAC not responding and the BMPlus 3000 LED's are off

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tnormile
Posts: 3
Joined: Wed Jun 09, 2021 12:41 pm

HVAC not responding and the BMPlus 3000 LED's are off

Post by tnormile »

Hi,

I have a two-zone system: Bryant Condensing Gas Furnace and AC with an EWC BMPPlus 3000 Rev B Zone control system.
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 did notice that the C1 and C2 capacitors are not obviously blown/burnt but the top aluminum parts of the capacitors look like they have a small little bit of paper coming out of them.
We can’t afford to have a costly repair now so I’m wondering if I buy a replacement board and configure the DIP switches and wiring like the old board will that get us up and running again ?

Thanks
Tom
John B.
Posts: 23
Joined: Fri Mar 13, 2009 8:57 am

Re: HVAC not responding and the BMPlus 3000 LED's are off

Post by John B. »

tnormile,

Sorry for the late response. We have had extremely high tech call volume and have not paid sufficient attention to the forum.

Sorry your BMP failed and 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 suppose a voltage spike, transient or short circuit occurred to blow the furnace fuse and damaged the BMP incoming power components as well. I assume at this point you have already replaced the BMP and all is ok?....Please let us know.
John Brown :geek:
tnormile
Posts: 3
Joined: Wed Jun 09, 2021 12:41 pm

Re: HVAC not responding and the BMPlus 3000 LED's are off

Post by tnormile »

Hi John

Thanks for the fast reply ! I haven't replaced to card yet - It's due to arrive in a few days. I wanted to check if I put the DIP switch setting etc on the new board the same as the bad board will I be good to go ? Also can you send me a link to a recommended transformer and I will put a dedicated transformer for the BMPlus

Thanks again John !

Tom
tnormile
Posts: 3
Joined: Wed Jun 09, 2021 12:41 pm

Re: HVAC not responding and the BMPlus 3000 LED's are off

Post by tnormile »

Hi John and community.

I've ordered my 24v transformer and my replacement BMPlus 3000 card. While I am waiting can anybody give me some tips on bypassing the card so that I can manually turn on AC or fan in my two zones? The card is dead but there's 24V coming in. (I think I can jumper from one side of the board to another )

Thanks

Tom
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