Weil McLain GV90+ Boiler Won't Stay Lit

mantazz679

Hello,

I was hoping I would be able to get some help regarding my Boiler that won't stay lit.

I have posted a youtube video here that demonstrates the issue that I have been having.

https://www.youtube.com/watch?v=uTT0Ia6k0B0

Essentially what is happening is the flame will initially light, but then the flame will go out. The system appears to be trying to re-light periodically, but fails. If I manually power the boiler off, and turn it back on, it will light, but then it will go back out again after a few minutes, and then attempt to relight itself again and fail. The linked video is about 13 minutes long, and has a pinned comment which shows the points where the flame goes on & off, and reset attempts are made.

This is a Weil McLain GV90+ Series 2 model. I had replaced the Module Control Unit a few years ago, because the first one was faulty. It was replaced with an upgraded part. I did inspect the Module Control Unit today, and it looked fine. I didn't see any fried circuits like I did on the one I replaced a few years ago.

I also replaced the ignitor a week ago in the hopes that would fix the problem. Replacing the ignitor didn't seem to help with the issue, as the problem is still occurring.

I took a quick snap of the pressure gauge as well. It should be attached to the posting.


Let me know if there is any more information I can provide.

Thank you.

EdTheHeaterMan

There is a condensation drain somewhere in that thing. see if it is clogged with crap. Just a wild guess here... When was the last time someone preformed maintenance on that boiler?

Service on a boiler can mean that someone replaced a part that failed. That does not mean that a complete maintenance was performed. Now if you find the condensate trap is clogged and you clean it out... That is also a service call, NOT complete maintenance!

So have the boiler "serviced" annually. That means have it cleaned and tuned up and all the items on the maintenance checklist performed before there is a problem.

Jamie Hall

I notice that the flame indicator light goes out, but all the other lights stay on. This means either that the flame goes out by itself for some reason, or that something is reducing the gas flow below where it can sustain, or that the control isn't getting the word that the flame is present.

It may be the control board. Or it may be a bad connection in any one of the wiring harnesses (or a bad ground), or a problem with the gas supply. Beyond that, without being there, can't help you much.

mantazz679

Thank you Jamie and Edward for the insights!

I cleaned out the condensate trap as suggested, as there it was filled with rusty metal chunks. I don't think it has been cleaned for at least a few years.

I do recall that the condensate trap had gotten clogged before a few years ago, but last time this caused the boiler to make a popping sound. It is interesting that this time it decided to have a different disfunction. I don't quite understand why.

The boiler has been working properly for the last 12 hours at least . I am not sure if there are other underlying issues, but I would think the suggestion of having the boiler serviced regularly is a good idea.

The only issue here in Wisconsin in my region is that most houses are newer with forced air, and I feel that getting qualified repair technician that knows a lot about these high efficiency boilers is hard to come by.

I had a technician come by last week to troubleshoot this issue, and he couldn't figure out the problem. I gave him over $100 for the pleasure of stopping by. He did check wiring and other things, but didn't solve the problem. This doesn't give me much confidence that annual service would actually do much. Anyway, just my jaded opinion at the moment. I could be wrong!

Thanks guys!

HVACNUT

The complete maintenance procedure is in the I&O manual. It even shows how to clear the drain and clean the recuperator.
The only thing I don't like about those boilers is they don't offer a location for a combustion test. It needs to be taken at the vent termination outside. 

GGross

HVACNUT said:

The complete maintenance procedure is in the I&O manual. It even shows how to clear the drain and clean the recuperator.
The only thing I don't like about those boilers is they don't offer a location for a combustion test. It needs to be taken at the vent termination outside. 

Couldn't you cut in a fitting for your analyzer? Centrotherm and Duravent both offer lengths with test ports built in.

Tom_133

HVACNUT said:

The complete maintenance procedure is in the I&O manual. It even shows how to clear the drain and clean the recuperator.
The only thing I don't like about those boilers is they don't offer a location for a combustion test. It needs to be taken at the vent termination outside. 

What I have found is the manometer hooked up on the gas valve and making sure its right where Weil McLain says it should be has made it super easy to get it right.