Bryant 355MAV Furnace And A/C Blower Not Starting - HVAC - Page 3 - DIY Chatroom Home Improvement Forum
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Old 08-07-2012, 10:43 AM   #31
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Blower issues


I also have an 11 year old 355MAV with blower issues.
After the blower stopped working it flashed both 44 and 41 codes.
Tech replaced the motor module and the unit ramped up and started working but only at low speed, still flashing 44 code.
Tech says the hi speed motor winding is bad and that we need to replace the entire motor $1600
HELP!?!?
Thanks in adanvce

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Old 02-01-2014, 01:03 PM   #32
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How I fixed my problem


Quote:
Originally Posted by rajar2 View Post
Similar problem to another Bryant 355MAV owner.
I hope someone can send me the Bryant check out procedures for a troubleshooting a blower motor that does not start.

"Code 41 is the blower motor failed a test and is outside it’s speed range by 10 percent.. It’s got 25 steps.?" Can anybody email me these procedures?
Both my furnace and A/C begin to go through their initial start-up cycles and completes everything OK, gas comes on and lights fine up to when the main blower motor should come on, but it does not start to turn at all - never. At this point the furnace shuts down. Similar results when I start the A/C.
I have the Installation manual and have checked the error message from performing the Component test. Inducer motor starts on Low speed, then Hi-speed, then hot surface ignitor lights up the gas and is on for 20 seconds, then it dies. The blower does not start its low, then high speed cycles. The Fault code is #41 - I get 4 flashes on Green LED followed by 1 on Yellow LED. This sequence keeps repeating. FU1 fuse on the panel is OK and am still looking for FU2. Any ideas?


I had the same problem and was determined to fix it myslf after the $1300 estimate I got to replace my blower motor. It in fact was not the actual motor, but the thermistor inside the black hub cap attached to the motor. I ordered the thermistor for $5.15 from Digi-Key, part #495-2123-ND, it is a little larger than the original, but same specs as the old one. It took me a couple of hours for dis-assembly and re-assembly, but well worth the $1100+ in savings!!! Thanks for all the help from the forum!!!!!!!!!

Last edited by 1HandyMatt; 02-01-2014 at 01:10 PM. Reason: typo
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Old 09-13-2015, 06:28 PM   #33
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Another success story


Thanks to all for an excellent thread. I too have a Bryant 355MAV that quit working after 16 years with error codes 44/41. I went through the Troubleshooting Guide and got to the conclusion to Replace Control Board. After discovering this thread I removed the blower assembly, removed the controller board, and inspected the Thermister. It was by no means fried, but did have a small burn mark along one lead, like so.

I ordered the #570-1059-ND Thermister from Digikey.com (and 3 spares) for a total of $16, put it in, and works like a charm.

Notes
  • A T15 security bit is needed to remove the blower motor controller boards from the hub. I bought a set of these from HarborFreight years ago and have only needed to use them twice before. But they are sure nice to have when you need them.
  • I wasted 4+ hours attempting to verify that the blower was not functioning, and naively thought I could just hot wire it. But there's already 120V to the motor from B1,B2 on the Furnace Control Board, so spin-up of the motor is controlled by the 5 control lines going from the PLA to the motor.
  • At the back of the Troubleshooting Guide is APPENDIX D—Quick Motor Test Procedure, and I tried following that. Its a PITA because the controller won't work if any of the connectors are unplugged, so one has to bridge the connector in place to get a voltage reading. Got a No to both 39 and 40, which then goes to 22-Replace furnace control board. So after 4+ hours I decided to see if the Thermister did the trick, which it did.
Attached Thumbnails
Bryant 355MAV furnace and A/C blower not starting-img_2268a.jpg  

Last edited by ff_mac; 09-13-2015 at 06:29 PM. Reason: added how long I've had it.
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Old 09-13-2015, 06:42 PM   #34
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Good work and thanks for the input.
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Old 10-07-2015, 12:57 AM   #35
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Another Bryant 355MAV owner with a blown blower... Great posts in this and related threads, but nothing looks like a clear answer, so hopefully ya'll are up for some more remote troubleshooting...

Symptoms: No main fan blower.

History: Purchased/installed in 2001. Heat, no AC, but we run in CF mode during summer months, often for 1-2 weeks at a time (low speed). Fan failure noted about 2 weeks ago. We have had several power outages recently, all planned service events by utility.

Self test proceeds thru all steps except last 2 main fan tests. Code 41: Blower outside valid speed range

Likely problems (Based on DIY Chats): lose solder connection on main control board or Blown Thermistor.

Pulled control board. Lots of dust, but it looks pretty new. Small amount of corrosion on pins behind 11 circuit connector (24v, "PL1" on diagram in manual). No sign of component failure or lose solder. Have pics if I can figure out how to post.
Wiring all looked OK, connections solid, no sign of heat or shorting. Board=HK42FZ012

Pulled Fan. Mine is a right-hand horizontal in the basement, so this was not easy. Control board mount has to be removed first, but in the end it was not that hard either.
Dis-assembled motor control: No obvious signs of overheating on circuit board.
Thermistor looks great. Tested 1 Ohm resistance... not sure how to test this component, but it looks like it does pass a current, but this was tested in-place, so I'm not sure of there might be a parallel circuit capable of passing current as well.
Bottom "potted" section looks new.
One of the capacitors shows some sign of... something. Could be corrosion/leakage? Not sure how to test the capacitors as they are soldered in place (same issue as Thermistor)
Tested all 3 fan circuits, each showed about 10 ohms resistance. My meter uses 1 AA battery, and I got a small amount of fan movement out of each of the circuits just from the meter current. Pretty cool, and seemed like a good indication motor is sound.

Tomorrow, I may try the "emergency heat mode", but do not have much hope on that one. This mode bypasses the microprocessor and calls for high speed fan immediately, so is a difference sequence than the self-test.

It has been really dry out here in CA, so I thought condensate trap could have dried out, perhaps confusing a sensor, but there are no sensors in the trap. Seems this unit senses issues with condensate drain by readings from pressure sensors connected to tubes connecting various components. These tubes all appear to be undamaged and fully intact. Pretty sure issues here would throw a different code, but I'm ready to test just about anything...
Thanks in advance for your puzzle solving!
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Old 10-07-2015, 11:37 AM   #36
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Quote:
Originally Posted by yuri View Post
There are 3 LARGE capacitors in those motors and GE recommends you wait 1/2 hr B4 doing any work on that module so they self discharge. These are BIG ones and can seriously hurt you.
Thanks for the reminder... these are not toys!

My unit has only 2, although there appears room for more. Is number of capacitors related to HP rating, or type of capacitor? A number of references recommend ensuring discharge by shorting the circuit (bridging capacitor terminals with a metal tool). Think this may be a good way to confirm they have completely self-discharged, but probably not a good way to quickly discharge them.
How do these units discharge? Looks like via small chips (resistors?) incorporated into the back side of the circuit board, or is the discharge function built into these capacitors?
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Old 10-07-2015, 03:32 PM   #37
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Update: I've posted pictures in my album
http://www.diychatroom.com/members/k...byrant-mav355/
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Old 10-10-2015, 12:26 AM   #38
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Quote:
Originally Posted by yuri View Post
There are 3 LARGE capacitors in those motors and GE recommends you wait 1/2 hr B4 doing any work on that module so they self discharge. These are BIG ones and can seriously hurt you.
Any recommendations on how to test/troubleshoot capacitors? I'm having issues with blower fan, and the only component with any odd look is capacitors, although the gook could easily be something else dripped down (my right-hand installation results in upside down fan motor unit). Have a look at my album for pic of capacitors.
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Old 10-10-2015, 03:55 AM   #39
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It's unlikely they are bad. The most accurate way is to remove them and test with a capacitance meter. You could try ohming across them while installed but it's difficult to say what the results will be. An experienced person should be able to tell that they are neither shorted or open from changes in the reading but that's about it.
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Old 11-05-2015, 02:03 PM   #40
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Tried "emergency heat mode", blower still does not work.
I am leaning towards ordering a replacement motor control module.

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