Constant Fan option ( 355 Bav Bryant )

[awsomeears]

Constant Fan needs to be adjusted on a 355 bav/cav 3-stage furnace to a nice LOW setting for 24/7 air purification ~

Thermostat is a standard Honeywell Pro600

We all know with an Evolution Stat you can easily adjust LOW/MED/HIGH but with a non communication you can ( I say can as I'm assuming ) adjust the CF dip switches.

I'm experiencing no luck...

SW1 bank ( 1 thorough 8 ) dip switch 5 is set to Manual a/c or CF
CF bank when set to 525 CFM or 700 CFM the fan doesn't change one bit, sounds like a JET and the blower tonnage is 42....

Has anyone adjusted the Constant Fan speed for those customers with a standard thermostat who would like to move air flow 24/7 at a lower speed ?

Thanks

[rundawg]

Try this procedure:

Continuous Blower Speed Selection from Thermostat

To select different continuous-blower airflows from the room thermostat, momentarily turn off the FAN switch or push-button on the room thermostat for 1-3 seconds after the blower motor BLWM is operating. The furnace control CPU will shift the continuous-blower airflow from the factory setting to the next highest CF selection airflow. Momentarily turning off the FAN switch again at the thermostat will shift the continuous blower airflow up one more increment. If you repeat this procedure enough you will eventually shift the continuous blower airflow to the lowest CF selection. The selection can be changed as many times as desired and is stored in the memory to be automatically used following a power interruption.

This is from the service manual.

[awsomeears]

I did just that and nothing different happened...

As we speak all of the Dip switches are in Default aka off for the CF or A/C

[rundawg]

What is the full model number?

With the CF switchs off - the default airflow is either 1050 cfm or 1750 cfm

[awsomeears]

I think it was 355BAV042060

Yes with them off it sounded like a god dam JET !!!

The subject about CF was brought up for comfort and he said " Its to dam loud " to run. I said no way put it on low ( I'm used to Evolution Control setting it to LOW ) and your good to go...

[rundawg]

Is this a two stage thermostat and 2 stage cooling?

The Air Conditioning Relay Disable Jumper (ACRDJ) on the board must be disconnected to allow thermostat control of the outdoor unit staging, and If I'm not mistaken, the blower motor also.

[awsomeears]

Is this a two stage thermostat and 2 stage cooling?

The Air Conditioning Relay Disable Jumper (ACRDJ) on the board must be disconnected to allow thermostat control of the outdoor unit staging, and If I'm not mistaken, the blower motor also.

1 stage Pro 6000
1 stage A/C
355bav is 3 stage...

[rundawg]

Other than making sure the tstat is sending out 24v on "G" to the board during continuous fan, I'm out of ideas.

You might try resetting the entire unit - power off and re-selecting dip switches to make sure you don't have one sticking.

May be time to call Carrier Tech support and see what they say. Might be a board issue.