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

chaxey

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

Here's a link to the manual for the info code:


https://www.manualslib.com/manual/189671/Weil-Mclain-Ultra-Ultra-105.html?page=20#manual

chaxey

Here's the error code, e-29

https://www.manualslib.com/manual/189671/Weil-Mclain-Ultra-Ultra-105.html?page=27#manual

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

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

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

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

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

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.

chaxey

The saga continues... End of last summer, the issue went away completely with the hot weather behind us. Summer 2022, the issue has resumed.

I have replaced the igniter, cleaned out the sump and drain, checked all molex connectors, jiggled and Fonzied everything I can. I have a maintenance kit/gasket in the mail and will clean out the chamber soon.

I cannot find any reference to a pressure sensor or centrifugal switch that @HVACNUT had made reference to. My regular plumber and I are stumped. He has a backup blower motor that might fit that we are going to eventually swap in, but have low confidence this will solve the problem.

My theory is that the intake / and exhaust flu are getting too hot as they are in direct hot sunlight, and positioned close together next to an outdoor shower stall that I think might be trapping hot air and humidity. 2-3 years ago before the issue presented, we had a huge maple tree in this area providing 24/7 shade, and the shower did not exist. My plumber thinks I'm nuts, and he may be right.

I contacted WM customer service, and they told me 99.9% sure I need a new blower, but I just can't make heads or tails why if the temperature outside is north of 85F this thing won't function, yet if it's cooler for 12 hours it operates just fine.

I was going to order return/supply sensor and a flue temp sensor replacement, but fear I'm just throwing bad money after good and guessing. I don't see any other sensors that can be ordered for the Ultra 155 s2.

http://igate.northernplumbing.com/partsbreakdowns/wm/383500403.pdf

chaxey

The other thing that is odd is if I get the E29 code, the first 2 times it presents, I can reset the unit and it seems to work fine. On the 3rd reset, it goes into the 6_32 lockout and will not restart. At this point, I shut down the power to the whole system, and I thought this was resolving the issue as this solved the problem several times reliably.

But this doesn't seem to be the case as today this didn't work. That being said, maybe the blower finally gave up the ghost. Or the fact that the temp never dropped significantly this AM and we have had unbelievable heat and humidity in Massachusetts the last 2 days. My thikning was that after being shut down for several hours at night when the temperature was down 20 degrees, this was eliminating the detected condition throwing the error.

Jamie Hall

Well now. You are getting a quite specific code -- blower motor failure. However. Like so many of these codes, it may be lying to you. The thing to find out -- and I'm not an expert on these units, so I haven't a clue -- is what, exactly, is telling the controller that the blower motor has failed? There has to be some kind of sensor or sensing circuit to do that. Others have mentioned an air flow proving switch or a centrifugal switch on the blower motor. Quite possible. However, there are other ways to sense a motor failure, such as excess or not enough current draw on the blower motor circuit, and those sensors would likely be on the control board itself. You really need to find out, if you can, what tells the controller that the blower motor has failed and make sure that that is not fooling you.

mattmia2

Was a combustion test done recently? Maybe it is failing to fire consistently when it is hot out when the air is hotter and lower density and the microprocessor is interpreting that as fan failure.

If there is a centrifugal switch it is part of the motor and probably all one connector.

Ceacel

Has any of the technicians who were there to work on it called Weil while on site ?
they’ll get a different set of questions than you the homeowner will. 

109A_5

@chaxey,

Code 29
Blower signal not zero when it should be — Burner off until signal condition corrected

1 Change display to Information mode — if INFO #6 shows 6._32, the blower has failed.
2 Possible strong wind blowing against vent turning blower wheel, correct venting.
3 Defective blower.
4 Defective control module.

If you are sure "2 Possible strong wind blowing against vent turning blower wheel, correct venting." is not the problem (and it is actually not turning) than it seems there is only three things involved.

1. The blower assembly (but not the actual blower motor).
2. The wiring harness and connectors and crimped pins.
3. The control module.

The actual blower motor may be fine. The centrifugal switch or RPM sensor or speed control (if any) in the blower motor assembly maybe intermittent. Keeping the motor spinning when not commanded to or reporting spinning when it is actually not spinning. Apparently the control module thinks the blower is spinning when it should not be.

Since the manufacture supplies no other truly good troubleshooting information and does not define the function of the 4 wires between the the blower the control module (X2-1, 2, 3, 4) to facilitate further testing sadly you or a tech have to guess. Inspect the wiring harness closely, poorly crimped connector pins can be elusive. If it has not been done yet I would re-seat (unplug and plug back in) the connectors of the wiring harness at the blower motor and at the control board. Also inspect the pin fitment of those connectors. Change the blower assembly, change the control board in that order over time. Or you could go from the least expensive part to the most expensive part. I'm thinking the manufacture would recommend replacing the blower assembly first.

chaxey said:

The other thing that is odd is if I get the E29 code, the first 2 times it presents, I can reset the unit and it seems to work fine. On the 3rd reset, it goes into the 6_32 lockout and will not restart. At this point, I shut down the power to the whole system, and I thought this was resolving the issue as this solved the problem several times reliably.

If this process is consistent and repeatable it may have been defined by the software engineer to get more attention to the unit if the same error codes persist (since they are not truly being resolved).

chaxey

109A_5 said:

@chaxey,


If this process is consistent and repeatable it may have been defined by the software engineer to get more attention to the unit if the same error codes persist (since they are not truly being resolved).

I am not 100% sure the "reset sequence" is repeatable as it is usually several hours if not days between attempts, but seems that way. Today the heat and humidity never really dropped off over night, so I was unable to get the unit to reset at all, so day 3 of the cold shower and angry wife. Usually overnight I can get it to fire back up.

There hasn't been much breeze/wind, but I have been suspicious of the location of the flue/intake as they are close to each other and not well spaced near a fence panel, so was thinking the intake is being disrupted by the flue outflow, or the temp between the sun/heat plus flue outpipe is superheating the intake air.

Weil McLain has suggested I go immediately to the Blower replacement. Which I'd be fine with, if I could find a part! Backorder for 8-10 weeks!


I had seen that pinout and diagram before, but it was a little over my head. I will try to reseat, crimp the molex connectors but my hesitation on thinking that is the problem is the fact that hte weather seems to be the #1 predictive nature of the issue and not sure hwo that would play into an electrical connection.

The unit itself needs a basic service and may be gummed up, so will start with that. I do not see any other sensors to buy so suspect that most of this is onboard the blower itself and not serviceable.

Thank you to all for the advice given thus far, truly appreciated.

EdTheHeaterMan

Try taking the air intake off of the boiler. Let the combustion air come from the boiler room. Make sure there are doors open to the boiler room to allow for ample combustion air during this test. This can be done by just removing the front cover from the boiler.

The reason I am suggestion this is something that you said earlier. "2-3 years ago before the issue presented, we had a huge maple tree in this area providing 24/7 shade, and the shower did not exist." This is just the type of thinking that no one does when it comes to solving these elusive problems. I like to ask things like "What has changed since the problem was nonexistent?" and no one ever thinks of trees or fences.

By removing the air intake from the location near the fence panel you will eliminate one of the possible problems. Recirculation of flue gas and possible higher intake temperatures as the problem will be gone. That is a first step that costs nothing.

chaxey

So a bit new info after actually printing and reading the manual... I went through the more detailed lockout details process:

Last code thrown: 29
Sequence when lockout occurred: 5=Checking air flow
Supply temp at time of lockout: 98
Return temp at time of lockout: 98
Type of call: DHW
Outdoor sensor temperature: 118

No real surprises here, we knew the error code was E-29. I do not however thin the outdoor temp is correct. I found the Outdoor temp to be way off earlier today when originally checking sensor readings. I think it was registering 105F at about 10am, which was impossible given that the Outdoor Reset sensor is in the shade and outdoor temp was roughly 88F. And while hot on Friday when that 118f reading was captured, it never eclipsed 95F degrees, though perhaps in direct sunlight?

I thought I'd try resetting the unit with the sensor disabled, but no luck there.

The sequence of lockout checks reads sequentially as 1-Prepurge, 2-ignition, 3, space heat on, 4:dhw on, 5=checking airflow, H=High Fire, L=Low Fire.

So my assumption is that it's making it through prepurge, ignition and dhw signalling, but then detecting airflow issues either due to busted blower or some intake/outtake issues.

I think next test will be Ed suggests to rule out the intake/flue configuration and location.

chaxey

Now that I'm thinkign of it, I ran all last summer with the outdoor reset disconnected and still the issue persisted, so my test today of disconnecting it was sorta a wasted effort as I knew that not to be a contributor.

chaxey

I just ran the furnace with the cover off, so sucking in cooler air from our basement and it made no difference.  I do not see any flame in the observation glass.  The blower does turn, and seems to spin up faster when being reset but also slowly spins at standby. I think it makes a slight hiss when spinning, but doesn’t sound awful. 

The drain line was full of water, which I emptied., but none of this had any affect.  Also checked and reseated all connections on the motor and main board and all seem good. 

109A_5

chaxey said:

but also slowly spins at standby. I think it makes a slight hiss when spinning, but doesn’t sound awful.

Code 29
Blower signal not zero when it should be

To me these two things means a control module that is unhappy with its blower.
Apparently the control module thinks the blower is spinning when it should not be.
Apparently the control module is correct and it sounds like the blower is spinning slowly when it should not be.

If the electronics on the blower assembly where the 4 wires go to has a thermally aggravated intermittent or just an intermittent defect causing the blower motor to spin when it is not suppose to the control module is detecting that defect (when it happens).

It seems you have witnessed your blower problem. The actual 'blower motor' may be fine, it seems the control electronics for the blower motor in the blower assembly is the issue. Since I doubt the control module would command the blower to spin slowly if spinning slowly is never a valid state.

Backorder for 8-10 weeks! That sucks !!! Did you check eBay ?

109A_5

@chaxey, You may want to verify this from another source, if possible. Seems your blower motor assembly is discontinued.

https://www.sidharvey.com/documents/UNI-85285_Broc.pdf

PDF page 252

383-500-035




It would not surprise me if your grief is caused by a bad solder connection on the circuit board in the blower assembly.

chaxey

109A_5 said:

It would not surprise me if your grief is caused by a bad solder connection on the circuit board in the blower assembly.

I totally agree. The solder used now is so brittle, I think a joint is gone or shorting and based on what I observed last night does seem as though the blower is constant on, which sounds like a bad thing.

I do think the blower is discontinued, but unsure - weil told me that the same blower is used on the Ultra 155 Series 4 which is still available for retail. They were trying to sell that as a positive as if i bought a new series 4, i could keep this blower as a backup someday (assuming I could find one). Yippee.

chaxey

109A_5 said:

chaxey said:

but also slowly spins at standby. I think it makes a slight hiss when spinning, but doesn’t sound awful.

It seems you have witnessed your blower problem. The actual 'blower motor' may be fine, it seems the control electronics for the blower motor in the blower assembly is the issue. Since I doubt the control module would command the blower to spin slowly if spinning slowly is never a valid state.

Backorder for 8-10 weeks! That sucks !!! Did you check eBay ?

Agree with the assessment... Checked ebay, no dice. Found a few potentially at a few online distributors and a place that might rebuild them.

At this point, I think the last year or 2 of symptoms and the outdoor temperature correlation was just circumstantial and the joint was solder just getting progressively worse. Maybe temp helped slightly aggravate.

chaxey

I found a blower motor locally for 550$... I am going to pick it up tomorrow. Can a novice install this safely? I am not sure I can wait for my plumber, he's swamped.

109A_5

chaxey said:

Can a novice install this safely?

I'm sure it is possible, however that said, it is very dependent on the skills and the tools the novice has. Has the novice been a cashier their whole life with no hobbies using tools or are they a Master Automotive Tech ? See where I am going here ? If you mangle something a plumber may not bail you out and if they do it certainly will cost more. Working on equipment with limited parts availability can be a touchy situation.

About the only advice I would have if you choose to do it yourself is; Shut the AC Power Off, do not break, crack or deform anything that has to remain in the unit, carefully clean off any old gasket material, don't loose any fasteners, snug things down evenly, use the correct tools, don't get any debris into the unit, put everything back as it was, take pictures if necessary, check your work thoroughly, follow any instructions that come with the replacement part, don't be in a hurry.

Plumbers have years of experience so they may make the job look easy and they should have the correct tools and know what to do when things are going badly (and realize when things are going badly).

Having your old blower repaired if the cost is reasonable may not be a bad idea if the boiler is otherwise in reasonable condition.

chaxey

Thanks. I will have my plumber handle this, as I am not sure if I could replace this new blower easily if I make a mistake and mangle it… if I knew I could get another maybe old take a leap…

pedmec

most likely your control signal (the 4 wire molex) is loose inside the motor or is getting wet on the internal circuit board. just replace the motor assembly. its plug and play. just make sure your piping under the cover is not leaking. the tubing on the ultras tend to develop leaks on the manufacturing piping. i have replaced the manufacturer piping on plenty of ultras. the blower motor will suck the moisture in on the cooling fan side and damage the circuitry in the motor

109A_5

pedmec said:

control signal (the 4 wire molex) is loose inside the motor

@pedmec, I'm curious, by "loose" you mean a connector pin fitment issue, or failed solder connections of the molex connector pins to the circuit board or other ?

chaxey

109A_5 said:

control signal (the 4 wire molex) is loose inside the motor

@pedmec, I'm curious, by "loose" you mean a connector pin fitment issue, or failed solder connections of the molex connector pins to the circuit board or other ?

Guessing the solder joints, pins seem ok.  I think the theory makes sense with corrosion and a leak. I will examine once removed. 

Kicker… outside air temp just dropped below 79 for the first time in 5 days to 67 degrees… And guess what?  The blower started working again! 

109A_5

@chaxey, If a through analysis of the situation (like in a lab) was done, you may find since the blower runs when it is not suppose to it may constantly draw in outside air. So when the outside temperature drops below a certain point it cools down the blower assembly enough because the cooler air is flowing into the cabinet. Then it works.

When you did the test that EdTheHeaterMan defined what was the air temperature around the boiler ? Maybe it was not cool enough. Or not enough time was given to cool down the blower assembly.

If it acts up again before the blower is changed out, a test with a source of cool air or air conditioned air introduced into the combustion air intake may be interesting. An awkward test to set up but it may help prove a point.

One place I worked was huge, the folks there sat a window air conditioner on an old desk well inside the building and they sat in front of the cool side of the A/C unit to cool down. It was funny to me, apparently worked for them.

As much as corrosion could be an issue and there can be multiple problems, it really seem like a thermally intermittent solid state device or cracked or never soldered properly solder joint.

chaxey

109A_5 said:

@chaxey, If a through analysis of the situation (like in a lab) was done, you may find since the blower runs when it is not suppose to it may constantly draw in outside air. So when the outside temperature drops below a certain point it cools down the blower assembly enough because the cooler air is flowing into the cabinet. Then it works.

When you did the test that EdTheHeaterMan defined what was the air temperature around the boiler ? Maybe it was not cool enough. Or not enough time was given to cool down the blower assembly.

When I pulled the jacket off, the basement temp was probably around 72-73ish, which typically seems to be 'cool' enough, but to your point the test may be invalid as the air and or cooling effect must be present for a longer duration. That being said, I fiddled with it for about 30-60 min with the jacket off, but the power off for most of that time.

For context I would add that when the temp first dropped yesterday and I attempted to restart the burner, it did not take despite the outside temp in the mid-60s. After a few hours past the temp drop is when I was able to successfully restart.

chaxey

Well, we gave up and just went for broke. Replaced the blower, ignitor, intake/outlet temp sensors, flue sensor and all gaskets after giving it a good cleaning.

Not exactly sure how it made it in there, but we found a few acorns inside the unit (but not the owner)... How a mouse made it in there and survived, I'll never know.

Anyway, we may not know if this resolved the issue until our next 90F degree day, but the only thing left that we didn't replace is basically the mainboard and the valve.

Upon inspection of the old blower, I didn't see anything notably corroded, but the entire unit was brittle/dirty; the main power female molex connector was definitely loose. The motor turns freely and had no 'smells'. A heatsink on one chip was visibly bent perhaps browned, but I was really grasping for soemthing out of the ordinary. Maybe a bad joint at one of the molex connections is probably my best guess.

Wanted to express my genuine thanks to all of you who listened and offered guidance in resolving the issue. Best to you all!

109A_5

@chaxey, With that wholesale change-out hopefully you would be good shape for a long time. Acorns may be a bit big for a mouse, I'm thinking a squirrel, probably not from the old maple tree. You may want to put screens over your air intake and exhaust pipes. There are commercially made inserts that go into the end of the pipes.

As far as temperature dependent solder joints you may need a 10X loupe (or the like) to do the inspection. If it is a thermally intermittent component you may not find it with visual inspection.