Log in

View Full Version : Bryant Plus 90 350MAV - No heat in the morning


4FanTrashCan
Mar 16, 2010, 07:52 AM
First post!

All,
I have a Bryant Plus 90 350MAV on propane. Yesterday I woke up to a 58degree house. Night/Morning temperature is set to be 65 degrees on digital thermostat. Thermostat stated "In Recovery" on display that morning and would not control the HVAC system even when elevating temp manually. I was able to get the unit to work by shutting power off and then back on to the HVAC unit (unfortunetly I did not check for error codes). That same morning I also heard the inducer motor start, but only run for maybe ?3 seconds? And then shut down. This was not the blower motor that I heard. The unit ran perfectly all day long.
This morning same issue, cold house and "In Recovery" stated on the thermostat. I am use to "In Recovery" for use in A/C mode, but not for Heat.
Sorry, still no codes to report, but will certainly obtain them if it fails again. I cannot get the unit to fail as of right now.

Diagnostics so far include:

Verified wiring connections (all good)
Cleaned high temp sensor (not dirty)
Cleaned flame sense rod (not dirty)
Verified air filter (not dirty)
Cleaned condensation trap and lines (somewhat gunky)
Verified pressure switch operates (by pulling and reinstalling vacuum line when unit operates properly)
Verified inducer motor capacitor
Inducer motor spins freely

What could cause the inducer motor to shut off shortly (3-5 sec) after being told to turn on? Suspect board but want to know how to verify.

I am currently shutting off the heat for the day to try and reproduce the night time situation.

Any help would be greatly appreciated. Thank you.

4FanTrashCan
Mar 16, 2010, 10:25 PM
Attempting to simulate issue by lowering the house temp to 65 through the day produced no results. The furnace kicked in as soon as the thermostat reached 64 degrees.
All operations function properly as long as the inducer motor does not get turned off prematurely.

Current operation when working properly:
Thermostat requests heat
Inducer motor starts
Relay on board trips (few seconds later) (assume from pressure switch)
Ignitor starts to glow
Gas solenoid trips
Burners light
Blower begins to run
House gets warm :-)
Set temp is reached
Blower shuts off
Rinse and repeat!

Any input on the culprit that would shut down the inducer motor within 3-5 sec of starting up and cause the HVAC to not respond to an automatic or manual heat request from the thermostat (Honeywell CT3650 digital/programmable)?
I understand the "In Recovery" message to indicate that the thermostat is turning on the HVAC a little at a time in order to gradually get the house from 65 degrees to 67 degrees at the set time of 6:45 am. Amazing what reading the manual can do for you. I will shut this "Smart Response" feature off and observe for changes. Thanks in advance for any input.

Joshdta
Mar 17, 2010, 05:21 AM
Does it work fine if you lock you stat to a set temp, not using the program? Also. Sounds like you may have a drain problem. At night time when the temp is still colder the drain could be stopped up causing the pressure switch to kick in and out.