Munchkin 140M firing: spark electrode angle?

ErikV

After 4 years trouble-free, the Munchkin 140M boiler threw an F09 last week and would not fire after several reset attempts. Getting gas, getting spark when electrode is pulled from chamber. Venting and condensate drainage good.



After a couple hours, and long after cleaning the electrode surface, I finally got it to ignite by slightly adjusting the spark electrode angle while it was fully inserted (but not tightened) and sparking. Tried to maintain the electrode in that position and tightened it down, good for a week.



This morning it was F09 again and cold in the house. Unscrewed the electrode, slightly titled it away from the burner, fired right up. If I reseated the electrode back to flush ("normal" mounting position) during the spark, the burner would cut out. So I am thinking it is shorting out on the burner tube or something else (?) inside the chamber.



The house is still reheating so the boiler hasn't needed to spark again, but obviously I'm going to need to deal with this longer term. So here are the questions!



What about *SLIGHTLY* bending the electrode in the apparently required angle? Can I just put a thin layer of something under the gasket to change the angle, or will that ruin the gasket seal and cause other problems? Maybe I should just replace the electrode? Or, is the best choice getting someone in for service, e.g. need to clean out the chamber, hopefully they can better pinpoint the problem? An issue with that is I am in a semi-small town in Iowa, I have not found a tech who seems to know Munchkin boilers. Installers included. Maybe not such a big deal if I have truly ID'ed the problem now.

Alan (California Radiant) Forbes

Munchkin F09

I wouldn't do anything to change the angle of the electrode other that to make sure it has a ¼" gap.



Things that come to mind:



Check your flame sensor; make sure it's clean.



Check your combustion settings; your gas mixture may not be right.  See "Item G: Test Mode" on page 32.

[url=http://www.htproducts.com/literature/lp-147.pdf]http://www.htproducts.com/literature/lp-147.pdf



Check your burner; the bolts that hold the burner to the round cover provide proper grounding for ignition.  Remove and clean if tarnished or dirty.  Your technician will have to turn off and disconnect the gas from the gas valve, remove the wiring from the electrode, pilot and rectifier probe, gas valve and the two molex plugs that attach to the blower; remove the circle of bolts that holds on the burner cover and remove the assembly.  You now have the burner, cover, blower and gas valve in your hand.  I remove the burner, wash it in the sink and dry it out really well.  I also wire brush the bolts and use sandcloth around the bolts holes on the burner and cover.  While you've got your burner removed, check the combustion chamber and heat exchanger for debris and remove with a vacuum cleaner.  Reassemble.

Dennis

Munchkin

Check to make sure the electrode is not touching the refractory material, some times when removing the electrode you can damage the refractory enough to impinge on the electrode.



I would make sure that flame sensor is really clean.

ErikV

Munchkin pics

Many thanks for the replies.



OK will not mess with the spark electrode. Did check the gap before. And in fact if I look in the little window when it is burning, I see space between the red hot spark electrode and the burner. The burner surface does look a little flaky.



The exterior mounting bolts look pretty clean, but I don't know. When removing the burner cover, does the air channel come off with it? It is sealed by some kind of sealant, wondering if any gaskets need to be replaced in the sequence to remove and clean the nuts to insure proper grounding



The first thing I did was thoroughly clean the electrode and probe with emery cloth (I know, maybe Scotch Brite would have been better ...), they were pretty shiny. That didn't fix it, the only consistent thing to make it fire is to adjust the angle of the spark electrode.



About the refractory material, how can you tell if it is touching? By removing the burner cover as described? Seems hard to look through the mounting hole.



Pics to show the condition of the mounting bolts, etc.

Mark Eatherton

Bad signs...

The corrosion on the aluminum and the black iron pipe are an indication of exhaust gas being recycled into the burner and control vestibule.



You need a pro to check it out and see what is going on. Remeber, you are messing with fire, electricity and carbon monoxide here..



ME

ErikV

intake-exhaust piping incorrect?

Thanks. I am not averse to bringing in a pro just having a hard time finding one. Will keep working on that this week.



hmmm I looked carefully at the installation manual and at the intake and exhaust venting. PVC pipe lengths, tilt, support, diameter etc all seems to be in spec *EXCEPT* the left-right center-to-center spacing outside the house wall is a hair over 5" not "between 8 inches and 6 feet" (see specification pic below from Munchkin manual).  Exhaust extends out exactly 12 inches beyond intake tee.



Is that proximity enough to cause exhaust gas contamination?  Wonder if I should discuss this with the installers. Installation was 4-5 years ago.

Mark Eatherton

Prevailing wind direction..

can cause the exhaust plume to curl right back around and wash the intake with flue gasses.



This is why I am a BIG proponent for taking the terminations to the roof, and terminating them 12" to 18" vertically away from each other. Never had a recycle problem doing that.



Where are you located?



You could do the submarine periscope thing on the wall and get some more separation. Elbow the exhaust up and then out, and the intake down, maintaining required clearance to the ground. Not pretty, but functional.



ME

tim smith

I see no mention of cleaning heat x???

Been running fine for 4 years but not been pulled apart and cleaned? You need to have this done. Along with clean the burner nuts and flanges as noted above. I would bet you are backing up condensate in boiler. Also will probably need new target wall due to water/heat damage.  Good luck. Tim

ErikV

location

Located near Ames, Iowa. Presumably there is a qualified tech to be had in Des Moines  (about an hour), just no recommendations.



The intake could easily be periscoped up, leaving exhaust where it is. Equivalent lengths are almost identical right now, could maybe add 2 feet to intake.



The firing problem (or solution) seems even like it could be air mixture, corrected by just the right (small) gap size around the spark electrode base. Once going, it will ignite just fine all day, has stopped working the last two nights during the setback. Haven't tried any additional fixes since my first post here.

Alan (California Radiant) Forbes

Clarification

The bolts that I was talking about in my posting are not the bolts that you see on the outside of the boiler.  Once you remove the round access cover/air channel/blower assembly, you will see the burner bolted on the other side of the cover.  These are the bolts that need to be checked and cleaned periodically for proper grounding.



And it sounds like you and Mr. Eatherton have found something that may be causing the problems.

Slimpickins

what Tim said and

In addition to what Tim mentioned about having a new target wall handy,

you will need to have the burner gasket. They're usually trash when you

remover the burners screws to clean. You have to remove the target wall

to clean exchanger and it's probably in bad shape already. More than

likely the screw that holds the target wall in place is stripped and

impossible to remove so you'll have to take the target wall out in

pieces. I just put a little red high temp silicone on the new target

wall and put in place, the burner end will hold it in place once

reinstalled. Anyone else have a other solution to that?



All that aside, you do need a qualified Munchkin guy to do this. Not saying you can't but having all the right equipment is the key, CO detector, gas detector, combustion analyzer, etc. Good luck!

ErikV

Inside the ignition chamber

So I had a look (couple pics below):

- lots of debris, coils need badly to be cleaned

- burner is a little chewed up around the mounting flange, coincident with some damage to the refractory.

- target wall ceramic cover is wet to the touch, still serviceable but assume needs replacing



I washed the burner, cleaned the screws and their mount surfaces, vacuumed the chamber, reassembled *WITHOUT* a burner gasket (it was wasted like Slim said). Fired right up. Lack of gasket makes me very nervous but the whole reason I did this was, as of 2 p.m. I got a call at work it was not running again. Had not seen Slim's post.



I have tomorrow off will get a burner gasket and a tech in here with test equipment.



Plan of action, in order; ASAP:

- replace the burner gasket (do ceramics now if I can get them?)

- tech in to sniff, analyze combustion

Next few weeks (house is filling up for Xmas):

- condensate issue: not sure how to proceed. Ask tech. Boiler is

perfectly level, It should pitch to the back, could that be the problem?

- clean the heat transfer chamber

- at that time replace anything not already replaced

- Is the burner ok, or need or be replaced? I can ask the tech too.

Lower priority, e.g. by spring:

- reroute intake/exhasut piping



More comments encouraged, thanks all. Pics are right when I opened it.

Alan (California Radiant) Forbes

Combustion chamber

and the heat exchanger coils actually look OK for that many years; just clean them up.



It's your burner that looks bad.  Ouch - something is not right there.



I believe if you clear up the issues with recycling of exhaust gases and dial in your CO levels on your gas valve that you will be OK.  Of course, it looks as though you need to replace your burner and refractory.

Wayco Wayne_2

upgrades for Munchkins

I work on Munchkins a lot. I always replace the refractories, both of them. The new ones are much better and made of a more durable material. I always clean the burner bolts with a wire brush and spray with WD 40. Cleaning sensor and electrode are par for the course. Always install a new burner gasket. I keep a box of them in the front of my service van.  I love replacing the 925 control with the upgraded 926 control. Longer post purge time helps protect the blower from damage from heat traveling up from the HX after boiler turns off. High voltage rectification that uses both the flame sensor AND the electrode for sensing flame. I checked one the othe day. 8.3 rectification signal. Sweet!!! After all the upgrades dial in gas air mixture with a digital analyzer and it will work better than ever before. I install a union inside the boiler so taking off the burner door for the annual maintenance is easier. Always squeeze and flush out the rubber drain tube. It can build up junk from dust and byproducts of combustion over time and clog up. Squeezing it can help break up hard deposits.  Good luck. WW

Alan (California Radiant) Forbes

Heat Transfer Products

It would have been nice to have someone from HTP join in this thread.  I know they make an appearance sometimes, but with all the problems that we've seen with Munchkins, you'd think they would scan this board regularly.  We used to see Chuck Shaw, but unfortunately he is no longer with them.



Thanks for the information, Wayne.  That's good stuff to know.

ErikV

Running without a burner gasket?

Yes, thanks much Wayne, great info from somebody who services them a lot. Will definitely replace both ceramics. Since the burner is pricey, I won't be ponying up for a 926 control

board right now. But protecting that blower motor sounds like a good

idea, with what I've read about troubles with that part.



Have found a source for a burner gaskets today - 2.5 hours away.



Any thoughts on running this boiler for a couple days with no burner gasket, then do the job when shipping comes in?

Slimpickins

I'd say ok

You're ok running it without the gasket temporarily. Not a chance for much of a gas leak with positive press from the inducer. Sounds like you might go for cleaning it yourself and why not, you've gone this far. I see you  It looks like you have a nut holding your target wall on, much better than the Phillips head screw they use now.



I use a nylon vegetable brush first to knock the crud loose, then use a shop vac to vacuum. Get yourself some CLR and mix with water and spray down the heat exchanger really good, let soak and brush out with vegetable brush again. Flush with water, hook up a hose to the water side of your indirect tank or any hose bib. I put a nozzle on hose to control better and use some pressure to rinse. Also, an old credit card to get between the grooves helps. Yep, like Wayne said squeezing the condensate trap helps. Rinse it out until it runs clear.



Reassemble with the new target wall, burner gasket and door refractory.   I check with a level on the right hand manifold to see if the boiler tilts back a little bit to help the condensate to drain better. If theres some play, you may be able to shim the front up a little, don't force it too much., At least use soap bubbles to check your gas union for leaks. 



I usually go with the, "Don't try this at home" theme with customers but obviously you're fairly mechanical to get as far as you did. Still at least find someone that can set the combustion on the Munchie. Good luck

gerry_6

CHECK THE SWIRL PLATE TOO.

 DITTO what is already said The swirl plate mixes air with gas  it is mounted between the gas valve and blower from the looks of the blower picture  I bet you need a new swirl plate too .  If your not buying the 926 control the existing 925 control software can be upgraded to get the long fan postpurge  and longer flame rectification time its almost as good as a 926 upgrade.   Also I use some weather stripping to seal up the cover to cabinet and fill in any other hole and spaces  with insulation try to make it sealed tight  here is why, this is a common problem I seen with side wall venting when boiler is in standby and home is often unusually tight construction outside air easily infiltrates into home thru the exhaust and intake vents as the flow of air comes thru the exhaust, and heat exchanger it is very humid with acidic condensate  this causes the deteration of swirl plate and burner gasket early blower failure this can be compounded  with short cycling and condensate blockage . When you find the  Technician  he should have  a laptop and training  to do the software upgrade on your 925 control also check the fault history you can see total number of ignition cycles and total hours heating and do the math to get your average number cycles per hour  the lower the number of cylces per hour the better . 

That will get you started . Gerry Alder      

tim smith

Re: Running without gasket

We too always carry gaskets, target walls & electrodes as needed. I would not run without gaskets as you very likely will experience lockouts or delayed ignition. I would bet there is a company around your area that has 1/2" ceramic high temp sheets. You can cut your own if you have to, to get by. Re: blocked condensate. Remove drain line from trap at back. Take burner mount plate off heatx  Tape end of shop vac to trap and after cleaning coils from inside flush water down through bottom of heat x to shop vac. Squeeze rubber trap as you do it to break up loose stuck material. This usually does a good job. Use old credit card, (the one that's max'd out   and go between tubes to clear stuck debris from gaps. Again, this is for experienced tech so I can't recommend you do this!  Just a side note. Tim

Mark Eatherton

A couple of things...

and this is directed at pro's and non pro's (cons?)



When handling the used refractory, TAKE EXTREME precautions. The stuff breaks down under fire and is called chrysolites and it is BAD NEWS if you inhale it. It is in all the manufacturers O&M manuals I have seen.



Secondly, the use of soap for detecting leaks is a dangerous proposition. I am not allowed to post photgraphs because the case is still in litigation, but those brass gas cocks with the red handles on them HATE ammonia based detergents. The picture shows the brass SHEARED off at the parts that normally thread together over the ball.



If you're going to use detergent to leak detect, RINSE IT THROUGHLY WHEN YOU ARE DONE, OR SUFFER THE CONSEQUENCES.



Instead, you should be using an approved liquid leak detector (ammonia free). Graingers even sells one with antifreeze already mixed in.



Lastly, I would NOT recommend running the burner without the gasket. Great place for CO to leak into the house through the leaky jacket. If it were roof vented, there might be a chance for atmospheric powered stack action to alleviate this, but on a horizontal vent, slim to none. If nothing else, make a gasket out of RTV silicone that will peel off when the real gasket arrives.



Let's keep it safe out there...



ME

ErikV

Cleaned and basic repairs

Thanks all who have posted, this thread has answered a lot of questions and I finally understand the basics of how this Munchkin works, and some of the things that need to be done each year for maintenance.



Today the parts arrived and I cleaned the coils while replacing the refractory, burner+gasket, and target wall. ME - I was already wearing a respirator and being extremely careful with the ceramics, they look especially nasty and fluffy after moisture damage as I found them. It ran one day without the gasket, won't have to do that again I picked up a few spares.



Coils are much cleaner now but not squeaky clean (pics) I can go back in at the end of the season (and will, every season!)



Gerry was right the swirl plate is indeed ruined (pic), but I had already placed the parts order when he posted. So I'll replace that before the tech visits for combustion. The cork gasket on the blower assembly opposite the swirl plate is sticking out (pic), seemed odd.



Before cleaning the coils I checked the drain with a hose, it was flowing well. I performed clean-out maneuvers anyway but it seems like chamber problems (refractory, burner) were more likely due to flue gas intake and fours winters of neglect, than to backed up condensation.



Does the pitted ceramic on that flame rectifier probe look bad to anyone (pic)?

gerry_6

you may understand the cork gasket if you see an older munchkin

The cork gasket comes with the blower it really fits the model just older than yours that had the air/gas venturi with honeywell gasvalve . I'm not sure why there would even be a cork gasket there on your blower with a dungs gasvalve and swirlplate .

 I'd be surprised if it actually pitted the ceramic looks like dirty on the surface I think that you can just sand the ceramic clean and smooth on the rectification probe .   Gerry Alder

Steve Whitbeck

Munchkin

Your Munchkin is drawing in it's own exhaust gasses. You need to raise the exhaust pipe so that it is at least 18 inches higher than the intake.

Also the boiler is not draining properly. The refractories are water damaged.

Put a level on the front of the air transfer tube and see if the boiler is tipped slightly toward the back. The transfer tube is the flat plate you see in front when you take the boiler cover off.

If the plastic parts or the blower are going bad you have exhaust reversion.

NEVER use a concentric vent of any kind. ( I don't care that the install manuall says it is OK.)

I always seperate the intake and exhaust by at least 18 inches vertically.

bjwerti

Peerless / Munchkin PI-80 Spark Problem

I have a 2003 Peerless PI-80 NG (i.e. Munckhin) boiler that has worked well for 7years.  I have only replaced the spark electrode once about 3yrs ago.  It recently has started to ignite poorly and another new electrode didn't help.  Unit is clean inside.  I removed the burner from the front wall, and I securely tightened the burner's bolts after inspecting, but I didn't sand/clean the burner and wall before I screwed it back on.  Could that be my spark problem, or is that unrelated?

If I need a new control board, is there any way to upgrade my WHA Rev 0 board to the new Munchkin 926 board?  I know I can purchase the P125 upgrade kit, but that seems pretty outdated now.  Unfortunately Peerless never went beyond the P125 control whereas Munchkin has. Thanks.

bjwerti

Pictures of PI-80 with spark issue

Here are some pictures of the condition of the Peerless PI-80 boiler.  I took the burner off tonight & cleaned it near the bolt areas and I put a new burner gasket on too.  I noticed a small harline crack at one of the bolt holes, but it hasn't progressed into the burner so I assume it's not an issue of concern?

SUPER DAN P&H

Increasing Post Purge time?

I currently have a 925 control. I noticed my swirl plate is deteriorating since there is shavings below it. How can I manually extend the post purge time longer? Thanks,Dan.







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Steve Whitbeck

cracking

small cracks around the bolt holes of the burner are somewhat normal if the burner gets loose.

Make sure that the burner screws are tight.