Vibrating Munchkin boiler???

SUPER DAN P&H

Problem Solved!!!!

Finally,I was able to get my hands on a CO Analyzer. Once I made the proper adjustments to the Dungs gas valve. My boiler ran nice and quiet. Also that gas smell from my exhaust is gone too! Bye bye vibrating Munchkin! Thanks everyone for your input!

Jean-David Beyer

Witness dye is not enough.

The purple color for the cleaner-primer is all very well, but my former contractor did the intake and exhaust PVC pipes with it. The joints were all purple, so they had obviously been cleaned. Unfortunately, they forgot to use the cement on most of the joints. Then they put some thin black foam insulation on the pipes. Fortunately, this was all in my garage.



A year and a half later, the boiler locked out. We ultimately found out that the purple stuff is inadequate to cement pipe together, you have to use cement also. (No surprise.) So it is all fixed now, with a new control board also, even though the old one worked for a week as we investigated the source of the water. Condensate in the exhaust leaking out and running down between the insulation and the pipe, where it could not be seen.



It is interesting that the control board says, right on the front of the thing, that if it has been under water, it must be replaced. I mean everyone should know that, but there it was, in plain sight.

icesailor

Vibrating Munchkin:

And the cause of the noise was backfiring through the swirl plate. Combustion analysis and adjustments solved the problem. If you used it for any amount though, you may want to take it out and inspect it. It could have serious deterioration and need to be replaced. It will  only get worse. They make a modified plate that is resistant to the problem but they still have the problem.

I have my theories about it. I think that any gas boiler that uses a Gianonni type HX and fires a burner like this is susceptible to this. Some worse than others.

RobbieDo

Clear Primer

Not that this has to domwith your issues, I will read more. But as far as the primer, there is clear primer, you can see it with a UV light, in some areas it's legal by code other places it's not. You did a nice job, I will read all of the posts and see what I come up with, just the primer caught my eye.

icesailor

PVC Clear Primer

Because all PVC pipe is printed with the information of the pipe, if you clean it with clear primer, and you clean past the make-in, you will see that the color printing is removed. If you see the the printing go unobstructed into the socket of the fitting, it hasn't been cleaned. I put a liberal amount of cleaner on the pipe and clean it off with a clean rag. I also do the socket of the fitting. It should come cleanly off. Any purple primer I have ever used didn't come off and made a mess. IMO, it left the job looking unprofessional. There is another string here where 4 water heaters were connected with a 4" PVC vent. It is obvious to anyone who knows that the pipe and fittings were not cleaned. The plumbing inspector where I work would fail the inspection if I did that. 

SUPER DAN P&H

FINALLY PROBLEM SOLVED!!!

Who'd da thunk just replacing a little ol swirl plate would have cured the vibrating Munchkin boiler. I should have replaced it a year ago. The old one was in bad shape. Performed a good cleaning while I was in there. My Munchkin boiler rocks!!!

SUPER DAN P&H

swirl plate replacement

no more vibrations

SUPER DAN P&H

2

2

Charlie from wmass

any idea why the swirl plate

was bad? Glad you found the issue.

icesailor

Bad swirl plates:

I've been told by those in the know that I am wrong in my opinion but they can't give me contrary proof when I ask to be proven wrong.

I believe that the Dungs Valve has an ability to allow backfiring and the "swirl" that mixes air and gas through the venturi, can backfire and allow flame to swirl with the air and gas and burn through the plate. It seems to happen more with concentric vents but it can happen to any of them. Especially if there is something to block the free flow of exhaust. It is also more apt to start during low modulation firing.



If you had the plate in hand, you would see (like in the photo) that there are a group of vanes that are just missing. They have had the plastic so heated that they just broke off. If you flip the plate over, you can see there the flame or hot exhaust has been circulating through the venturi.

Swirl plate degradation is often blamed on "regurgitation" of exhaust gasses being sucked back into the intake.

If you make a careful observation of that burned swirl plate, you might come to the same conclusion that I have. No one has been able to convince me to the contrary or give me a provable hypothesis to the contrary. I'm still waiting.

If you can put a laptop on the brain and retrieve the codes, you will see a lot of retries. A symptom of flame failure. It will start slowly and then speed up over time.

SUPER DAN P&H

My ideas of premature failure.

Originally when I installed the air intake and discharge, I left a gap of only 12". Also, I didnt  calibrate the gas valve w/ a co meter( didnt have access to one). Also too cheap and proud to call in another plumber. It ran like that for probably a year before I addressed it. That probably caused the premature failure of the swirl plate. So shame on me and not the Munchkin product. I agree with what the ICE SAILOR is talking about. Regurgitation. The noise only happened during initial low fire modulation. Then ran quiet afterwards. Yet the heat will eventually creep back and deteriorate the swirl plate. Hopefully my 18" air intake/discharge gap adjustment and calibrated gas valve extend the life expectancy of this boiler to perform better in the future. Thanks for everyones input! Long live my Munchkin boiler!!!

Charlie from wmass

also thanks

for the update. People often disappear and we never find out if the problem is fixed or not.

SUPER DAN P&H

thank you.

Its important as a community to share our knowledge in order for us to grow. As plumbers or hvac contractors, we should be helping each brother instead of competing against each other. Its my privilege to work amongst great men.

icesailor

Setting up to Munch:

It is more important to set up Munchies up with a digital exhaust combustion analyzer. If it is a newer Munchie with the remote controller, the instruction manual list the CO and CO2 valves, and fan speeds for high and low fire. You need the gas pressure to get to these numbers. The controller will show you the fan speeds. The fan speed is part of setting the gas flow rate. It is all in the manual. If you haven't carefully read it, you need to read it until you understand it. You have to look at the chart to see what model Munchie you have and use those parameters. I can be as fussy as I want to be but if the fan speed  is very close, and the numbers are slightly out of range but close, it can be a bigger PITA to futz with the gas valve. "No good deed will be unpunished". But if you change swirl plates, you should go over the whole thing.

If you have a M80 Munchie and it is vented with 3" PVC, I find that it will have a problem venting and running on low fire and I have put 3"X2" PVC bushings in the exhaust to get more back pressure on low fire. They improved. I've extended concentric vents with a no-hub coupling and PVC pipe. If the vent faces the East or a prevailing winter wind direction, it may need something to stop direct wind from blowing back as hard. Take the burner off and look into the chamber. The last one was clean as a whistle with only a stray dehydrated insect on the bottom. I've seen others that were acting up that needed to cleaned out with CLR or Rid Lime.

SUPER DAN P&H

Ice man cometh

I did calibrate gas valve w/ HTP Tech Services. It was set up properly after the fact the swirl plate was damaged. She's good now. I clean combustion chamber every 1-1 1/2. She's squeeky clean & quiet. Thanks again.