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Weil Mclain gremlins... Ultra series 2 blower shuts off randomly... need help please!

chaxey Member Posts: 6
edited September 2021 in THE MAIN WALL
I've had 2 technicians look at this problem and all are confused /unable to help.

This all began at the beginning of summer, our Weil McLain Ultra Series II 155 would randomly shut down in the summer (so only running hot water) and issue a code E-29.

Not a good code as it indicates the blower motor has failed... Upon a reset to bypass the lockout, the boiler fires right back up, so the assumption was/is there was a temporary issue with flow that caused the board to shut it down. I'm totally speculating...

The error code would recurr randomly over the last summer, but did seem to correlate and happen on days that it was very hot out. This may be circumstantial. But in each case, the boiler reset solved the problem and hot water would return in 20-30 minutes or so.

On Monday, code e-29 returned (not hot out, so no heat on). Reset apparently worked as the code cleared and hotwater restored. Today, Wedensday, the system had another issue - unclear what the code was or if there was one, as my wife reset the boiler and didn't take notice if any code was presented... However, no hot water was produced and the system sat at 0-72 degrees and despite calls for hot water, no command was being sent to ignite/produce hot water.

Upon receiving angry words from wife due to lack of hot water, I returned home to inspect the furnace and found no error code, but info code step 6-32 was being issued. This translates per the manual to blower motor failure....

I called a local heating repair service advised them the blower likely needed to be replaced.... Upon arrival and inspection, all he did was jiggle the water reserve tank thermostat knob (which he said didn't really feel loose or at issue) and the thermostat clicked and hot water was requested and serviced.

My assumption is that this has nothing to do with him jiggling or adjusting the thermostat and instead the blower had just had a chance to cool down or reset or something...? Or maybe there was a deadspot on the thermostat for DHW?

I am not an expert and have just googled for all of this info so hoping an expert can set me straight as the 2 technicians that have come out have really been no help. Both were unwilling to replace the blower when it is proving to operate, yet clearly is having issues intermittently.

Sorry, i know TL:DR!


  • chaxey
    chaxey Member Posts: 6
    Here's the error code, e-29


    Change display to Information mode — if INFO #6 shows 6._32, the blower has1failed.2Possible strong wind blowing against vent turning blower wheel, correct venting.3Defective blower.4Defective control module.
  • chaxey
    chaxey Member Posts: 6
    The only other info I have is... I did replace the outdoor reset sensor over the summer. Our contractor when re-siding our house cut the wires and I had to replace it as it was corroded and left to the elements for too long before I noticed it.

    Per info code 4, the sensor was working and detecting the temperature today at 56 degrees F, which was correct/accurate so I do not suspect this to be part of the problem.
  • chaxey
    chaxey Member Posts: 6
    Actually - I have a new theory... We also had a natural gas generator installed over the summer. Wondering if maybe we lost power overnight and the unit kicked on and perhaps the system was starved of gas which caused a blower issue?
    EBEBRATT-Ed Member Posts: 11,996
    If it shows a blower motor error but the blower runs when reset look for an air proving switch. It's possible the blower motor is good but the air switch is not telling the control the blower is running. Remove the tube(s) to the air switch and blow them out and try that. Also check wiring from the blower motor and make sure the connections are tight
    HVACNUT Member Posts: 4,592
    edited September 2021
    Is the generator set for periodic test runs? Does it correlate with the boiler lockouts?
    If so then the meter, regulator, and/or pipe size is an issue. WM wants 5" wc with the boiler in high fire. Don't know if that would throw an E29 code though. 

    The 6_32 is just the information mode of the E29 soft lockout code showing blower failure. 
    How is venting and combustion air? No obstructions?
    Has anyone checked the drain? It could be condensate backing up inside the heat exchanger.
    Has the block ever been replaced due to drain issues?
    @EBEBRATT-Ed might be on the right track here as the Ultra doesn't have a pressure switch, but a centrifugal switch to prove minimum fan RPM. If the drain clogs (extremely common on Series 2), then it can lockout on a blower failure error.

    There are Molex connectors at the front and back of the blower. Make sure they're secure. 

    It's likely the blower itself is ok. They usually just die outright, or you'll hear the scream of a motor that wants to die.
  • chaxey
    chaxey Member Posts: 6
    Thank you both for the check list, I'll look at the above. AFAIK, there are no obstructions at last look but will double check, and will have to read up on the other suggestions. I don't have a full history on this unit as we bought the house and it was here, so I do not know who had been servicing it, or what had been replaced prior to us moving in. In the ~5 years I've had it, all we've really had to do was basic service, and replace the condensate pump and reset sensor.