Weil McLain AB-80H Control Board Fire

sgibb16

I installed an AB-80H to replace an older Munchkin Boiler that had developed a leak in it back in January 2022. 

Today I go into the basement and smell smoke/see smoke coming out of the front of my AB unit. I immediately unplugged it and turned off the gas. Upon some further investigation this is what I am dealing with. The control board is shot…. Any ideas what could have caused this? I originally thought maybe an issue with the circulator pumps but they seem to be working fine, and the fuse didn’t blow. 

Appreciate any insight. 

109A_5

Hello @sgibb16,
Well that made a mess, hopefully warranty will cover it. Maybe just a component failure or bad engineering. Is the Blue MOV intact ?
I suspect that area of the board controls the power to the fan and/or the circulator. However it may be part of the switching power supply to the Right and above.

I'd verify that fuse is the correct value.

sgibb16

@109A_5

I purchase and installed the unit myself, their warranty documentation says it has to be submitted by an HVAC company. I have someone who I can probably work that through, but I already ordered the replacement board. Which was not cheap… 

the blue MOV does appear to be intact from a limited visual inspection. It looks like the failure was after the white 24V relay you can see below the burned area. It think it controls the power to the circulator. 

I will double check the fuse but it is from the factory I know it hasn’t been changed. I’m also going to verify amperage the circulator is pulling tomorrow as well as a sanity check to make sure it’s not damaged. 

109A_5

Hello @sgibb16,
Is the up side of the white relay burned out or just heat scorched from something above it burning up ? The top side of the relay does not look that bad. If it is all coming out of your wallet I think I would try to verify the Fan and the Circulator current as best as possible. Maybe add some extra over-current protection for those devices.

What ever component started the event may be the most melted or destroyed.
What is at the tip of the Red arrow, maybe you can take a good picture of the replacement board in that area and post it.

HVACNUT

Any signs of water from above?

Unless you are the registered installer, don't go crazy ripping things out. WM will need verification from a certified tech to get warranty replacement. 

sgibb16

@109A_5

I tested the current on the circulator and it is reading properly, also verified the fuse is the correct 3.15A it calls for. 

Pulled the card out of the holder and got a few better pictures. Definitely seems like the small blue component was the cause of the failure. 

Also I searched the Honeywell part number that is listed on the board and found a few refurbished boards for MUCH cheaper than a new one with the Weil McLain PN. So I am going to go that route. 

sgibb16

@HVACNUT no signs of water. I found a refurbished card assy and am going to try that out. 

Jamie Hall

You might also spend a little time finding out what overloaded that melted mess to cause it to destroy itself... so the next one doesn't do the same thing. Just sayin'.

109A_5

Hello @sgibb16,
Looking at poor pictures on the web of other like boards that were not burned up, the light Blue component that had the meltdown was a Capacitor. Since there is a Euro presence of that board on the web I think that circuit is either for Power Factor Correction and/or automatic Input Voltage selection. The relay seems to be controlled from the low voltage circuitry to the left.

sgibb16

@109A_5

I hadn’t thought about automatic voltage selection but I think that makes sense. All of the euro wiring diagrams I can find online are almost identical and have power entering same pins on the board etc. 

The refurbished board I bought was from Europe so we will find out here before long. The PN printed on the board is identical so hopefully it works out.

Jamie Hall

I don't' think the capacitor was the source of the meltdown -- it was whatever was next to it that is really a mess. I still think it would be wise to troubleshoot a little and find out what, if anything, was overloaded...

sgibb16

@Jamie Hall 

I agree, I tested the circulator pump and checked out good, not drawing too much. I haven’t tested the blower, but I’m trying to determine the best way to
do that. 

Beyond those 2 things there really isn’t anything external on the high power side of the card. 

There weren’t any error codes when i shut down the system, and it was still running when i noticed the smell/smoke. 

Here is a picture of what the burned portion looked like previously (from online). 

realliveplumber

Since that is probably not from an installation error, I would think the manufacturer would be interested in your situation.

If that were in my house, I would be making phone calls, and sending emails, with photographs, until I had a satisfactory answer.

Larry Weingarten

Hi, It's sorta been hinted at, but how clean/stable is the power coming to the boiler? Perhaps some power conditioning, or at least a surge suppressor might be a good addition.

Yours, Larry

109A_5

Hello @sgibb16,
I still think most of the debris at the tip of the Red arrow in a previous post is the guts of the Capacitor, nothing else there with that much material.

I now think the transistor looking device (maybe SOT223) is a TRIAC for item 32 Central Heating Pump (see wiring diagram), either for a soft start or speed control and the relay is for full speed. Also it looks like there are may be two optocoulplers just above the majority of devastated area, but I can't make out the part numbers.

The Switch Mode Power Supply uses a TNY278GN which looks like it is good with an input Voltage range of 85 - 265 VAC.

The damaged Capacitor is probably for switching noise suppression or maybe part of a Snubber circuit.

The blower may need AC power and an external frequency source to make it turn at any significant speed.

109A_5

Hello @sgibb16,
Looks like the blower power just loops through the board for the fuse protection an it is not switched there.

sgibb16

@109A_5

you are correct it is an optocoupler I can only make out the PN in the larger one, smaller one is too damaged. The PN is EL3053 009v

sgibb16

@109A_5

Finally got the replacement European board in and am now home after some holiday travel. 

Started trying to get this thing to work today but ran into a couple issues. The system initially powered on and went through its normal start up procedure, displayed software version 04 which matches what my manual says and then went through its 5 min air purge procedure where it cycled the fan and pumps on and off for 5 minutes.

After that I got an error code F12 for DHW temperature sensor, which I don’t have as I have a heat only unit. Went through all the settings I could find via the “Configuration Mode” and “Transparent Parameters Mode” to set it up as a heat only unit. (Page 98)

https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Weil-Mclain-383-100-035-Install%20Instructions.pdf 

While I was in there I realized all the temperatures were in C not F which makes sense, so I just made sure all settings were in line with my manual.

I could not get it to bypass the DHW sensor no matter how much I changed settings, I eventually got a resistor and bypassed it and the F12 error code went away. 

I now have an F34 error code for low voltage which again makes sense because it’s looking for 220 from a European circuit. So it looks like there are some other settings buried in this board that need to be changed for it to work. 

Also here is the best manual I can find for a European equivalent, much less detailed compared to the Weil McLain manual. 

https://www.ferroli.com/media/1504105009.pdf 

Oh and I also noticed this manufacturers plate inside the unit.

109A_5

Hello @sgibb16,
You would think the input Voltage or 'County used in' would be software selectable. Same with the DHW function use. There could be a factory configuration menu that is not easy to get to unless you know how to find it. All the board numbers are exactly the same ? Maybe the vendor where you bought it from knows.

Possibly there is a resistor or a Zero Ohm surface mount resistor (a jumper) for the selections. Or a different value resistor for the input voltage expected (Voltage divider). You would have to compare the boards very closely.

I've also seen diodes also used as firmware selection in other equipment.

The Switch mode power supply chip may not care about the input Voltage but they may monitor it for other reasons, like Brown-outs or over-Voltage to protect other controlled devices.

sgibb16

@109A_5
Yes the PN on the board is the same, but maybe it’s just flashed different with slightly different software?

yes you would think it would be SW selectable, they have a voltage frequency SW selectable 50 or 60 Hz. 

There is a selection available for “Variable input switch functionality” not very clear what that is. Says default is supposed to be “4” but there is only 0, 1, or 2 available on this board… I tried all of them. 

Seems like I may have to just bite the bullet on the US PN board, looks like I will be able to recoup some costs and return this European one. 

109A_5

Hello @sgibb16,
It would not surprise me if a new board comes with factory default configuration and it can sense what features and supply voltage it has at install time. Once it self configures how often does the whole boiler move to another country. There is a beauty and a curse to software based devices.

I wonder if there is a way to put it back to factory default, other equipment has these features buried in the menu.

109A_5

Hello @sgibb16,
Is there a place to enter the model of your boiler ? It may do a lot of configuration simply by the Model Number entered.

sgibb16

@109A_5

There isn’t a place to enter the model, the manual has “default” settings by model number, but has a note that a replacement board is preconfigured to a certain model number that isn’t mine. And that you have to change certain parameters to set it to the appropriate model. 

There is some reset menus that I haven’t looked at much, probably a good place to look next. 

109A_5

Hello @sgibb16,

I wonder if you change the frequency the Voltage changes too.
Euro 220 VAC 50 Hz - USA/Canada 120 VAC 60 Hz.




You may be aware of the following.
Maybe not your boiler, but you may find this interesting after 5:00.

https://youtu.be/bE9BV5kdfts
Weil-McLain AquaBalance | Overview

Other biole; There are other videos on the Moderna, definitely some other menus you may already know about depending on what buttons you hold. Or what you hold at power up. Youtube "The Ferroli Man"

ferroli bluehelix factory reset
https://youtu.be/5rwQS8sDeP0

EBEBRATT-Ed

Reminds me of a 200-ton Carrier water cooled chiller we had that lost a control board.

After many, many calls to Carrier we were told they did not have a board for that chiller configured. We had to give them the exact Model and serial # and they would configure the board. When we get the board just plug it in and away we go.

Of course, our customer who used the chiller for process is screaming because it was going to take a week to get the board.

So the board shows up late one day and two of us head up there to get the chiller running. My partner puts the board in and is checking parameters and tries to start the chiller ...no go. He works on if for 20 min and is getting all frustrated, so he walks away and I (the guy who hates microprocessors) get into it.

After a couple of min, I find the problem.

We have a water-cooled chiller, and they programmed the board for an air-cooled chiller. Changed one parameter and we were online.

But remember.

They HAD to have the Exact model and serial #s

I trust no manufacturers.

PeteA

Great info on this thread. The Aqua Balance seems really thought out with regards to the access panels on each side being removable and the large tube diameters in the heat exchanger seems pretty forgiving and would make it easier to flush/clean if needed and for maintenance. The videos were great @109A_5
Only concern I have is the access to parts issue the OP @sgibb16 has to go through, It seems like he had to get a board from outside the country in order to make his repair!?! Thats terrifying to me that these things cost a couple of thousand bucks and these companies won't support the end users due to self-install even if it's not an install issue. Is that what you experienced @sgibb16 when you tried to get this board replaced or did you skip trying to get help from WM?
In general, is that the case with all of these high efficiency devices? That no company will support you regardless of whether the installer followed the recommendations to a tee or not?
As someone shopping for a new one this is making these high efficiency boilers less and less appealing.

HomerJSmith

The arrow is pointing to a full wave bridge rectifier. The capacitor is filtering the bridge output. I think that the rectifier diodes shorted out.

EBEBRATT-Ed

@PeteA

I don't have ton of Mod Con experience but have heard a lot of stories. Parts are expensive and not always in stock whether you are a legit installer or a homeowner.

Utica makes some Mod Cons and the company I worked for installed a few before I retired. They were supposedly USA made and we had no issues that I know of. But On this forum they are seldom mentioned. Don't know if no news is good news or maybe no one is installing them.

109A_5

HomerJSmith said:

The arrow is pointing to a full wave bridge rectifier. The capacitor is filtering the bridge output. I think that the rectifier diodes shorted out.

The arrow is NOT pointing to a full wave bridge rectifier, it is pointing to a TRIAC, BTA204.

sgibb16

@PeteA

There is good access to parts however they seem to be wildly marked up stateside. From Supplyhouse.com the new Weil McLain branded board was $750 or so, the total cost of the boiler 2 years ago was only $2200….

So that’s when I opted to roll the dice on the European board for $150. Ultimately I found one stateside for $450 that is getting delivered tomorrow and I will install it then. 

I reached out to Weil McLain technical support who basically just said yeah you need a new board. They referred me to the warranty department who has ignored my emails, I will be trying to follow up with a phone call tomorrow as well. Problem is WM warranty information basically says if you aren’t a certified installer they won’t do anything for you…. 

sgibb16

@109A_5

I did try the frequency swap and it didn’t perform any different. 

I did see those WM videos, but I have t seen the Ferrolli. I’ll start poking around those as well, thanks!

mattmia2

I bet that capacitor is an rfi suppression capacitor to ground and is a class y capacitor which is designed to open up if it fails so it won't cause a shock hazard and it failed.

PeteA

thanks @sgibb16
That is a pretty pricey circuit board which is all the more reason why you'd hope for warranty protection if it isn't something you've done wrong.
It's a shame when these bigger companies seem to just dump the support portions of the company down a black hole like that. Other industries are stepping up on the customer service side and it just stinks to hear when others drop off their customers and ignore them. It really does tarnish the brand and also raise concerns with others about what they might experience if they need help. A few posts above @EBEBRATT-Ed even mentions that it's not even just the self-installers struggling with support and parts for these things, it's even the pro's who are forced to tell customers it may be a while to get the parts needed for the repairs. I find that pretty scary for an industry that is really ready to be pushed out into the front of all of the older technologies we have used to heat our homes in the past because of the regulations being imposed on us all. These machines may have been around in Europe for many years but it's a young budding industry here and the manufacturers need to recognize the huge upside potential here in the states and ensure their reputation is intact by delivering the service and parts needed to help out all installers and repair folks.

mattmia2

Usually it is worded more along the lines of we may refuse warranty service to equipment not installed by a contractor. I think it more depends on how you ask and if it was installed properly. If the defect is the result of the install and it was installed by a dealer then they might end up eating the cost for the deaeler's mistake. If it was a homeowner that didn't follow the instruction then they are likely out of luck.

I might clean that board up and put in a new cap to get it running again. It depends on how badly the traces are damaged. Those double sided traces and vias are there to take heat away from the semiconductor and getting enough heat dissipation for that might be hard, the rest can be fixed with jumpers.

pecmsg

sgibb16 said:

@PeteA

There is good access to parts however they seem to be wildly marked up stateside. From Supplyhouse.com the new Weil McLain branded board was $750 or so, the total cost of the boiler 2 years ago was only $2200….

So that’s when I opted to roll the dice on the European board for $150. Ultimately I found one stateside for $450 that is getting delivered tomorrow and I will install it then. 

I reached out to Weil McLain technical support who basically just said yeah you need a new board. They referred me to the warranty department who has ignored my emails, I will be trying to follow up with a phone call tomorrow as well. Problem is WM warranty information basically says if you aren’t a certified installer they won’t do anything for you…. 

Pricings not allowed!

mattmia2

There is a good chance that their warranty people are working through the pile that accumulated over the holidays,

sgibb16

All,

New US replacement board arrived and I installed it this morning, everything appears to be working at the moment. 

I did notice some different PN’s of components but haven’t dove into what/if they were actually different. I already shipped back the European board for a refund. 

I appreciate all the feedback and time spent by everyone’s reply’s! 

109A_5

Hello @sgibb16,

It is good your heat is restored !!!

sgibb16 said:

I did notice some different PN’s of components but haven’t dove into what/if they were actually different.

I think they are the same basic parts, just with slightly different specifications. One becomes obsolete or otherwise unavailable so they use another similar one. Or a cost difference.

EBEBRATT-Ed

@PeteA

Mod con boiler have been around for probably 20 years or more. Th parts situation isn't getting any better and I don't think it ever will.

It's not just mod cons it's everything.

But parts that come from overseas is the worst.

I used to do start up on commercial sized Riello burners before I retired. 2 million , 3 million BTU/hour

On a high rise in Boston It had like 8 boilers in a tight boiler room. Someone had accidently smacked the plastic end bell on a burner motor and broken the cooling fan and the plastic shroud. It was a metric motor of course.

No big rush because they had 8 boilers but it took3 months. I told them to get a plastic fan blade and plastic end bell but they sent the whole motor. It had to come from Italy.

Another time was a Weishaupt burner that needed an oil pump. A Suntec oil pump like Beckett and Carlin use......but this pump was made in France to Viessmann specs.

Viessmann had NO stock in the US. They had to fly one in from France.

How do they get away with selling equipment when they have no parts in stock?

PeteA

Thanks @EBEBRATT-Ed
its actually pretty scary since sales folks tend to see opportunities with selling products to gain perks and make commissions for moving product but it’s the poor repair person and the customer that suffer the most with that type of business model.
i obviously don’t have any of the incredible experience that you guys/gals have but the 2 crown boilers (velocity) CI boilers I’ve installed seems to be built out of some decent materials and parts that appear to be readily available. The cast iron core is cast and stamped Burnham from what I’ve found in researching the equipment and the electronic controls even seem to be readily available.
i am really leaning on just buying another CI boiler from them and reusing my chimney that the previous homeowner stopped using when he had the combi installed.
then at that point my only decision will be to use a high efficiency hot water only unit or rig a plate heat exchanger up to the CI unit.
Decisions decisions

HomerJSmith

@109A_5 That's true.
Your photo of a bridge rectifier is a typical configuration with the filtering electrolytic cap. Yes it appears to be a triac. Consulting my electronic dictionary, your assessment is correct. That I think is where the failure occurred. I don't know how many techs check the polarity of the 120V coming into the unit, but I would check that I always do. Electricians rarely make that mistake, but is does happen. I always ask if there was any other electronic failures in the house, nearby lightening strikes, or the power company working on the street, etc.