Am having a problem with my Bryant 352MAV furnace. Intermittently, the furnace will fail to "run" and the status LED flashes a code 32. I did some troubleshooting on this a year ago and things seemed to be fine but now it's acting up again. Originally I disconnected all of the small diameter tubing that runs to the pressure switch assemblies and checked for moisture - they were dry. I did notice that one of the tubes had a pretty severe kink in it so I shortened that tube just enough to remove the kink and re-connected it. From that point on, the furnace seemed to work OK. Now, it's doing the same thing again. This morning, it failed to run so I opened up the panel to check the status LED - flashing a code 32. So, I reset the power to the furnace to observe what happens. As soon as the inducer motor starts, the LED starts flashing the code 32 again. Just on a whim, I tapped the pressure sensor assembly with my hand a few times and noticed that the status LED stopped flashing and went to a steady "on" state. The furnace then cycled normally, it ran for about an hour. I've seen some other posts that talk about these switch assemblies can be problematic - this particular furnace is about 7 years old or so. The switches are the original ones - they have external microswitches mounted to steel canisters. Are these likely the culprit or was it just coincidence that the tapping on the switches seemed to cure the problem?

hvac1000

More than likely you have found the problem. Do not try and replace the switch. Replace the entire part. Order the correct part for your unit since many of these parts have different perset settings.

The back of the blower door has a diagram for your unit with trouble codes listed.

KC13

Oxidized microswitch contacts. I'll bet you have the older-style metallic vacuum canisters. Seek out the new-style assembly - plastic canisters with the switch sealed inside. Typically the problem is with the switch having the orange and yellow wires connected to it. Wiggle the terminals a bit to scrub the contacts a little. This will buy you some time.

Darkstar777

Yes, it is the older style assemblies - external switches and metal cannisters. It looks like you have to replace both of them as an entire assembly. Are the new ones the same way or can they be replaced individually? Would there be any safety problem with bypassing the faulty switch? There does seem to be sufficient inducer draft by virtue of the fact that the switch does not drop out after I get it to actuate.

hvac1000

Would there be any safety problem with bypassing the faulty switch?

Yes these are safety devices themselves so do not bypass.

Darkstar777

After looking at the P/N on the pressure switch, it appears that an outfit called Tri-Delta Industries Inc. makes the pressure switch assembly. The existing P/N 326070-701 is available from a number of sources but I didn't see any switches that look to be of a newer style (plastic case/sealed switch) anywhere. What P/N should I be looking for if I want the newer style? My exact furnace model is 352MAV036080F AKA and the S/N is 3701A12964.

hvac1000

You might find that the dual pressure switch unit is not available in plastic as of this date. Also remember that most posters that help on this board are in the trade and many parts mentioned are OEM only from a factory distributer not after market or directly sold to consumers.

Tri Delta was bought by Honeywell back in 2002 I believe and all manufacturing was sent to Honeywells Mexico plant. The Ohio plant has been closed for years.

Below is a web page that shown the pictures of the available styles of switches and you will see the dual unit for your model is available in metal. Other single units are available in plastic as you can also see.

Bryant, Carrier & Payne Pressure switches.