Munchkin - noise and smell?

Chris_82

In all fairness to munchkin, see my other posts, the venting can vibrate harmonically especially when the wind is blowing outside, like the three bears, not to strong, but not to light either, kind of like blowing across the top of a soda bottle. This happens even if you follow the install instructions to a t. And it happens with many sealed combustion units, gas fireplaces as well!

On the other hand, they do have a troublesome two piece fan, it starts out as a one piece fan and takes a while to fail, but it turns into a multi piece fan and what your describing sounds just like what I have heard multiple times before. It vibrates like heck, making this rumbling and bellowing sound. Two things happen at this point 1. The fan impeller shroud separates and the remaining pieces jam the motor, the boiler locks out on no air. 2. The shroud separates and simply rests against the moving pieces AND all appears fine. However I am unable to get anyone at the factory to talk about this. This is the reason the new units have the speed sensor software lock out. With the fan running at reduced efficiency, which I have heard some people also remove the fractured shroud and put it back together, (the warranty replacement deposit is around $500.00 and this upsets a lot of techs as it takes them by surprise at the parts counter) more than one late night call I have heard of simply putting the unit back together and well see what happens and lo and behold it works fine? It will run but again I can't get any one to commit to the increased CO level, and it is increased. The smell is fairly common to many of the high efficiency crowd; however YOU must get someone who has, for lack of better description, smelled a number of units, to judge what is a concern versus low O2 flow type problems. Remember CO is odorless and colorless, but smelling the warm CO2 vapor isn’t something many are accustomed to. The warm slightly smelly vapor is a common adjustment and is also a reason not to push any code distance to the minimum.

KW in WI

Munchkin - noise and smell?

My HVAC installer is working on this - but I thought I'd query The Wall for some input too.

We have a Munchkin wall-hung boiler driving in-floor radiant system (above subfloor sandwich) with 9 zones + indirect DHW tank. Occassionally (and not consistently...at least now discernable patterns yet) there is a rumbling vibration from the boiler - can be heard throughout 2 story house (boiler in basement). Best way to explain it...sounds like the UPS truck just pulled into the driveway! I've only caught it in the act 2x. Vibration/noise is definitely from blower area above burner chamber. Flame is on, cooking just fine. Wasn't at the very end of satisfying a call for heat. End of the noise it makes a 'zipping closed' sound - like when you let the air out of a balloon - right at the end when it runs out - but not high pitched. I also noticed a nasty smell at that point (one time I was outside the house and smelled it from the exhaust - the other time I was standing in front of the boiler with the cover off).

OK, with that limited description - any guesses about where to start trouble shooting? HVAC guy is very good - but hasn't this problem before. Is working with tech support too.

Guy_6

Combustion

What were the combustion test results when the boiler was installed? If the boiler was set too "lean", you can get an erratic flame (and consequent noises), usually on low fire.

T Towne

Are you using the concentric vent kit?

Al Corelli

Noise.

Is the boiler vented to manufactuer's specifications?

tim smith

Munchkin noise

Sounds like to be either the combustion is off or the fan is dismantling itself. May have to pull fan and look at impellar and or do combustion check. Tim

R. Swatton

#1 combustion is off check co
#2 gas valve offset needs adjustment
#2 Gas piping maybe too small, only .5 wc drop from static to high fire
#3 gas regulator withing 15 feet of boiler.





Authorized Heat Tranfer Products Sevice Agent

KW in WI

some answers

I'll try to respond to some of the queries (given that I am NOT a boiler technician)

1) concentric exhaust kit (assuming this is a single pipe - multi-walled with exhaust and intake in one) - no, there are separate PVC runs for exhaust and intake

2) noise occurred during both time of wind - and times of dead calm

3) don't know the combustion test results from install

4) gas regulator is approx 40' from unit

5) Also, in the approx 8 weeks we've been running, we've had 2 F10 lock-outs and one F5 lockout.

6) fan sounds perfectly normal almost all of the time, noise is sporadic and not showing a pattern of consistency. No sounds like pieces and parts are flailing around in the housing.

7) I assume that the venting is installed according to the specs.

8) unit just did the noise again as I was getting home...I would describe portion of the noise to a sputtering outboard motor exhaust barely under the water (if that rings a bell with anyone out there!) )

I appreciate this toss about guys. Any info I can pass along to the HVAC techs as they pursue solutions will be appreciated. They've been a great crew to work with and are looking for a solution too.

Al Corelli

Check Drain

Check the condensate drain to make sure its free and clear, and that the vent hole in the coupling is open.

KW in WI

I pulled the condensation line out of the drain trap and puffed on it - seemed to be draining fine. I'll have to look at hole in fitting.

T Towne

KW

I mentioned the vent because my new Knight had this soent with a lockuot and it turned out to be the cover section of the concentric vent was not pushed in all the way. Pushed it in and no problems now!

T Towne

Lets try that again!!!

I mentioned the vent because my new Knight had this sound with a no flame lockout and it turned out to be the cover section of the concentric vent was not pushed in all the way. Pushed it in and no problems now!

KW in WI

again, concentric vent is single piping - with both exhaust and intake within the same outer 'sleeve' - two pipe in one, right? Not what I have.

Checked install manual - venting appears to be in accordance with specs.

Checked hole on condensate line fitting - it is clear

T Towne

kw

Yea, concentric is 2 pipes in one but the one I have is 2 different parts so you actually have to push the cover section on to the other.

T Towne

KW, sorry Iread your post wrong. I sse now that you do not have concentric vent

KW in WI

OK more info - caught it again

I was in the basement when it started making noise. 2 zones calling for heat. Watched combustion chamber window. As it was making noise, blue flame was in chamber - flame seemed to 'flutter' in accordance with the rumbling sound. Green flame-on sensor was lit. Blue flames went out in chamber, green light went off. Zones still calling for heat (lights on Taco controller). Vent fan ran briefly with no flame in chamber, Munchkin control board (LED water temp and flame sensor LED) flickered and twitched (if LEDs can actually twitch!) then flames relit - first blue and then turned over to orange.

Could this be a problem of some sort where the water returning from the zones is too hot? Or does this sound like a combustion problem?

Thanks once again - hopefully this is useful info

Bob Sweet

IMO

the co2 percentage is off (probably to low). The only way to know for sure is to have a combustion analysis done to see how it's burning.

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Al Corelli_2

Gas line.

Do you have courrogated gas line at or near the boiler?

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KW in WI

yes. black pipe to within approx 8' of the boiler - then 3/4" corrugated from there. Copper line feeds from propane tank to regulator on house.

bordy

Is it me or does it seem like every time theres a problem with a munchkin its when its hooked up to propane.

Unknown

I would have the LP

company check the quality of the propane. This has happened before and it is usually the fuel which is a problem. In some cases on the next fill of tanks the problem goes away.

Mark Wolff_2

Good Point Tim

I was just about to say the same thing as I read down the post, until I saw your comment. It sounds like you have a problem with the propane itself, not the system.

KW in WI

Probably stupid question but - what would be likely problems with the propane - excessive moisture? Wrong mix? Bad flugal valve? OK, I just made up that last one....

The LP tank was recently refilled. I believe that the most recent problems started after that fill (fill was last Monday) - I think the problems started on Wed that we noticed.

As I mentioned, we've had a couple of F10 lockouts and an F5 lockout prior to this. Was figuring that it was all in the same vein. But maybe not....

Chris_82

What has been the temp outside? prior post hinted at setting and distance, might need new prop regulator if water (snow) or cold is affecting it, a lot of temperature change takes place right at the regulator. Can be very annoying as performance of regulator changes with time of day, demand, etc.. Get supplier to change it as a first step. Should use a gage, and check pressure but more than once changing regulator fixed a problem. This will start a war but if in woods, without gage or new regulator, try adjusting diaphram. Looking in the sight glass, they change color all the time, from full orange to bairly perceptable. Pre purge fan runs no gas, this is normal. By the way some rumbling is normal, have you heard other munchkins running? At this point more likely than fan esp if new. But as they suggest yearly cleaning, check anyway. Propane can have more additional gases and contimainats than ngas, like sulfur, not usually a short term problem however.

Perry_2

Ineteresting design issue

So, lets be sure I understand this.

LP gas can be a range of mixtures of "Propane" and "Butane" - which is well known. Their are other trace hydrocarbon products that can also be their (as with all petrolium products) - but that is also well known.

Is the implication here that the Muchkin has problems running on some of the possible commercial mixes common to the term "LP gas." If so - the I would dispute that the real problem is with the LP (although changing to a different mix may solve the current symptoms) - but point out that this would be a design issue with the boiler.

There seems to be a reference to this having occured on other boilers (but not sure which brands). How interesting.

Clarifications anyone...

Perry

Brad Notter

Munchkin Noise

Been There. Done that.

It's most likely the "swirl plate". This is the grey plastic plate that has swirling fins. It is found just after the Dungs gas valve. It's function is to admit the proper mixture of air and gas and to create the rightflow pattern for combustion air. It is about 6" in diameter and screws on and off easily. The fins can become brittle and flake off and/or break, screwing up the gas/air injection. HTP told me this can be a result of flue gas being re-admitted to the intake so check your vent carefully to see that the exhaust is not being sucked back in.

I made my discovery on a 140M so I am not sure this is applicable to your model.

I hope I can save you some of the many hours it took me to land on the "swirl plate" as the culprit.

My ultimate solution to these types of problems...has been to install Viessmann boilers whenever possible...

No they didn't pay me to say that.

Gooze out.

Wayco Wayne_2

When I've had

noises like you've described, it has been an adjustment needed to the combustion. Perhaps the installer did not set it up with a digital combustion analyzer. I've had the good folks at HTP talk me through some adjustment problems. Perhaps your tech can do the same. WW

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Docman

Munchkin-noise and smell

I think Wayco Wayne is right on.i had a 140M that vibrated on cold light-off until it was " dialled in". The boiler lit off quiet when in a regular cycling mode, but if there was a call after a sustained quiet period ( summer domestic call) it would hum and vibrate on gas valve opening (LP)until an adjustment was made.Have your tech check with HTP.Best Regards, DJ.

KW in WI

initial suggestions from tech support

Just out of curiosity...some opinions? The HTP tech support line is suggesting two possibles at this point (HVAC tech is going to be out - possibly tomorrow)

1) bad gasket on chamber

2) bad flame sensor

Thoughts from anyone given the line of discussion thus far? Seems odd that it would be a gasket if it doesn't do it consistently.

BTW, tonight the noise has been lasting a few seconds than before. Outside temps tonight will be roughly -4 deg F - about 10 degrees colder than last night.

Mark Hunt

Please


if the tech shows up with no digital combustion equipment, call HTP and see if they can send someone that actually knows what they are doing to your house. Please!

These boilers require digital testing equipment to be set up properly. Not an option.

You are scaring me with the whole "odor" thing.

Got any birds? Are they OK?

Mark H

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Bob Sweet

It SURPRIZES me

that the MANUFACTURER, given the characteristics you have mentioned aren't a little more concerned with the combustion properties.

A flame sensor??

At the very least, to CYA get a combustion analysis done.

Second to flow requirements, and only second because in order to test you gotta keep the boiler running, is combustion testing. It amazes me how insignificant this part of the process is looked upon It's what seperates a finally tuned, worth the money spent piece of equipment from a money wasting, average joe, dangerous, run of the mill, over priced piece of ???


There have been situations when testing, that the co2 levels were below manufacturers specs and pegged my analyzer with levels of co in the range of 2500 - 3500 ppm. If that doesnt scare you I dont know what will.

Please have it tested.

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KW in WI

the solution

OK, tech was out, checked CO with digital combustion analyzer and found it set way at the bottom end of the 'acceptable' range. Adjusted it up from this 'too lean' position (as several on The Wall mentioned) and everything seems wonderful.

Just thought I'd post the follow-up

Thanks again for sharing your info and spending some head scratching time on this!

Bob Sweet

Did you mean co or co2??



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