Munchkin Boiler not firing up - no error codes


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Old 09-27-15, 12:44 PM
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Munchkin Boiler not firing up - no error codes

Greetings all,

Having issue with my Munchkin boiler. Had removed/replaced a bathroom radiator this summer and was advised that the system needed to be rebalanced.

Had my heating/plumbing dudes out and ended up needing a bit of plumbing work, but a day after that work the system fired up the next morning (did not fire up after my repair dude left the previous evening) and everything heated up just fine *except the bathroom radiator*.

Plumber had to come back to finish a couple things the next day (including putting a new overflow valve on the Munchkin), so I had him un-stick the radiator valve in the bathroom as well, thinking it was closed. It was, and is now open. All plumbing was done, water is in the system, air bled, pressure good, gas on, electric on.

But it doesn't fire up. All the work was finished over 2 days ago, wouldn't that be enough time for the pressure/whatever to "settle"....?? Is that even a thing??? Do I just need to be patient with this thing???

I'm stymied as to why the system turned on and worked a few days ago and does not now. Turned the power on/off a bazillion times, had already cleaned the contact(?)s inside, turned the gas off and on, OY! Really confused.

Any ideas are greatly appreciated.... TIA.
 
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Old 09-27-15, 02:47 PM
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Welcome to the forums.

Munchkin boilers is a trade line line. Please post a model number.

It worked a few days ago and then you drained it again.... correct ??
First thought comes to my mind is a problem with a low water shutoff.
 
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Old 09-27-15, 03:04 PM
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Without error codes, I think you would need to have a wiring diagram for the boiler and a voltmeter to troubleshoot "failure to fire." But the literature on the Munchkin website that I reviewed does not show a wiring diagram for any of the models. I assume you've verified the 120-V power and the thermostat circuit.

This is a complicated condensing boiler with solid-state controls. They are engineered in Germany with high-tech features, including a stainless steel heat exchanger, not frequently found on U.S. hot-water boilers. According to the Munchkin website, their units are warranted for 12 years. Were your HVAC "dudes" authorized Munchkin service techs? But, whatever, I would give Munchkin an opportunity to provide a service call.
 

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Old 09-27-15, 07:19 PM
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Sorry, it's the 80M model.

It worked a few days ago (after much plumbing) save for the one radiator not heating up. The system was not drained, just the tank (?).

And thanks for the welcome.
 
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Old 09-28-15, 07:41 AM
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Do you have a low water cutoff installed ?
It may be wired so as not to show a trouble code on the boiler.
 
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Old 09-28-15, 03:42 PM
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Hi PJMax - thanks for sticking with me here! And apologies, I'm new to this home ownership and this boiler. What would a low water cutoff look like....?
 
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Old 09-28-15, 05:16 PM
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There are different makes and models. You can look up "boiler low water cutoffs."

You could also post a few pictures of your boiler plumbing around the boiler.
http://www.doityourself.com/forum/el...-pictures.html
 
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Old 09-29-15, 07:22 AM
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Greetings again - well, the boiler fired up this morning with no complaints. About 60 hours after the plumbing/water repairs were made.

ANY idea why it would need this time, 2 and a half days, to "settle"....??? Is there a part or something that this would point to that I would perhaps need to look into replacing in the (near or far) future? Or something I should be immediately concerned about? Or is this just a quirk of the Munchkin 80M? Unit is at least 11 years old...

Waiting for a while to make sure those radiators get hot (they are warm, so far so good). Will keep you posted on that.

Thanks again for your help!
 
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Old 09-29-15, 03:13 PM
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Whelp,

The boiler fired up and heated everything. All radiators got warm. Not toasty hot, but warm.

Then it stopped working. Powered up and down, no error codes.

Turned the thermostat up and it sounded like the circulating pump (?) was working, but the fan/blower did not activate, the boiler did not begin it's self-cleaning/purge cycles so did not heat. No error cods.

Any other thoughts are greatly appreciated! TIA!
 
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Old 09-29-15, 04:40 PM
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Since you aren't getting any trouble codes you are either losing 120vac power or you are losing the thermostat connection to the boiler. I don't know if there is an indicator that lets you know you have 120v present. I also see a safety switch which is in the power line.

CHECK THERMOSTAT CIRCUIT(S)
1. Disconnect the two external wires connected to the boiler thermostat terminals (low voltage terminal strip terminals 5 and 6).

2. Connect a voltmeter across these two incoming wires. Close each thermostat, zone valve and relay in the external circuit one at a time and check the voltmeter reading across the incoming wires.

3. There should NEVER be a voltage reading on the wires.

4. If a voltage does occur under any condition, check and correct the external wiring. (This is a common problem when using 3-wire zone valves.)

5. Once the external thermostat circuit wiring is checked and corrected if necessary, reconnect the external thermostat circuit wires to boiler low voltage terminal strip

I'm seeing some discrepancy here.... the above troubleshooting info says terminals 5 and 6 but the low voltage wiring instructions say 7 and 8. So I don't which numbers are correct. The pic below is their location on the strip.

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Old 09-29-15, 05:00 PM
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ok thanks for all the info - really appreciate it!
 
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Old 09-29-15, 05:30 PM
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I'm wondering if the O.P. has the experience and equipment to troubleshoot as suggested.
 
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Old 09-29-15, 05:35 PM
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That remains to be seen but basically what I've posted is fairly easy to check and will confirm if there is a problem in the external wiring or the boiler itself. I wouldn't post any internal boiler wiring as that requires specialized knowledge.

You can also remove the two wires from the thermostat connection and place a short piece of wire across the thermostat terminals. If the boiler fires.... the problem is external.
 
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Old 09-30-15, 06:35 AM
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I don't have a ton of experience, which is why I'm here! I do have help and a housemate with a little electrical experience. If it proves to be beyond my skill/learning level, I'll bring in the professionals (electric is not something I want to mess with, for obvious reasons).

More importantly, I want to be informed if a professional is needed so then I can discuss intelligently with them - also why I posted!
 
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Old 09-30-15, 06:39 AM
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Thanks PJ! Boiler fired up again last night and heated everything quite well, then wouldn't fire up again later. Behaving very erratically.

Will attempt electrical tests and get back to you.
 
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Old 10-01-15, 09:07 AM
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Here's the latest... circulating pump?

Hi again,

The latest: The boiler fires up no problem. At some point it will shut off (before things get really hot upstairs, before I turn down the thermostat). It will not start up again for some time, but I hear some clicking and "struggling" coming from this little guy (first pic). Is this the circulating pump? It was also hotter than hades when I touched it briefly. Thoughts?

Second pic is of my boiler setup, note: I did not install this, I am a new home owner, and the house is a 100+ year old historic home. Just FYI.

My diagnosis (not knowing a thing about these things, mind you) is that this little guy may have been struggling after my bathroom renovation earlier this summer (when a radiator was taken out and the system was drained). It was found that the pipe that sent water to the boiler was 98% closed off with sediment and corrosion and what not (this pipe was replaced last week and water flow is fine again). Could the struggling, without any water in the system, have caused this guy to burn out? Even though the heat was not on at all during or after the radiator was replaced?

Hope that makes sense. :/

Thanks again...!

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Old 10-01-15, 11:55 AM
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Yes, that's the circulator pump. If it's clicking, maybe it has sediment in it like the incoming pipe did? It looks like you have a valve on one side of the pump. Hopefully, there is another valve that will isolate the other side. Then, there are four cap screws that fasten the cylindrical can to pump's body. Remove the can and inspect for any sediment or damage to the rotor or impeller.

Turn off the electric supply to the pump before working on it.
 
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Old 10-01-15, 05:00 PM
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Excellent, thanks. The other side of the pump is the overflow(?) valve that leads to nowhere (well, my floor really). So I'll turn off the electric supply, close off that valve and drain it out, and inspect the pump. Will keep you posted, thanks again for the help.
 
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Old 10-01-15, 05:37 PM
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The other side of the pump is the overflow(?) valve that leads to nowhere (well, my floor really).
I don't quite understand that post. The important thing is to isolate the pump from the pressure of the rest of the system. Otherwise, you'd probably need to drain the entire system.
 
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Old 10-01-15, 08:03 PM
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The yellow handled valve below the pump will drain out the whole system.

I'm not understanding your boiler piping there. I see two red shutoffs. One is in the heating loop with the pump. Trying to figure out what the other one is for. With both lines going to the front of the boiler it almost looks like a domestic hot water loop.

Are those two copper lines the only water connections to the boiler ? If yes..... closing both red valve will keep the water in the plumbing but the boiler will be emptied when the yellow valve is opened.
 
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Old 10-01-15, 08:22 PM
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Gotcha. Well, if need to drain the whole system, then so be it...!
 
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Old 10-01-15, 08:34 PM
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You and me both PJ (not understanding the lovely piping system). There are actually TWO boilers, as this is a two-flat home. Lots of messy pipes everywhere that criss-cross etc. Since there is only one water bill for the entire house (unlike gas and elec, where we have two meters) everything is quite hodge-podge.
 
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Old 10-02-15, 06:59 AM
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Is there a WARM WEATHER SHUTDOWN setting on that boiler?

If so, what is it set to?

Does the boiler only seem to fire up when it's below a certain outdoor temperature? (i.e. BELOW the WWSD setting?)
 
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Old 10-02-15, 01:18 PM
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Doesn't have that setting that I'm aware of, NJT. Boiler only fires up when the thermostat is turned up.
 
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Old 10-02-15, 01:29 PM
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Most modern modulating condensing boilers with outdoor reset do have WWSD ...

Take a look in the manual and see...

I believe the "Vision" system may be optional, but the manual says that you MIGHT have WWSD.

Function 7 -- Default value 68F -- Outdoor temperature that you wish the central heating should be disabled—(warm weather shutoff) Range: 41F to 122F
Go to your boiler and tell us the FULL model number from the data plate... or take a clear picture of it ...
 

Last edited by NJT; 10-02-15 at 02:39 PM.
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Old 10-03-15, 04:32 PM
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Hi all - update: I replaced the circulator pump, "that was easy"! Thanks to the people who put in the shut-off right above the pump, I did not have to drain the whole system.

Turned all the water back on, let the pressure get up, and turned it on. Boiler fired up, temp got up auto 116, highest it's been. Stayed on for the evening.

Fired it up again this morning, then lowered the temp on the thermostat. A while later raised the temp on the thermostat, and the boiler did NOT fire up.

So now I'm wondering if something is up with the things NJT mentioned. You are correct, sir, there is a WWSD. Also wondering if something was messed up with the "circulator post purge time" or anything else regarding the pump and thermostat... apologies again for my ignorance, I'm quite new to all of this. If nothing else I'd say the water is all ok now, what with all the plumbing I had done! The settings and electrical are on my mind now...

Attached are pics of my manual. I don't even know if there is a passcode that I need, more investigation is needed there. Many thanks!

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Old 10-03-15, 04:52 PM
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If the boiler is up to temperature..... it may not need to fire when thermostat calls for heat.
 
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Old 10-03-15, 05:33 PM
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Study that manual, learn what the various settings do, note if any are worlds away from the 'default' value.

Tell us what the settings are and we might see something way outta whack.

And please give us the full model number of the boiler from the data plate!
 
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Old 09-06-16, 12:29 PM
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update.... sort of

Greetings all!

So I'm sure you're all DYING to know what happened with my little munchkin last year. Main issue was plumbing: There was a 100 year old pipe that had very little water flow. Changed that out. Also changed out the Taco pump. Worked great all '15/16 winter season.

Just checked and cleaned the thing in prep for this coming season (cause I hear winter is coming) - basic stuff. Vacuumed out dust. Took some steel wool to the sensor rods (?) to clean them.

HOWEVER... little guy is not firing up. In fact, it's not even going through a purge cycle. Not recognizing that I have turned the thermostat up to 80. No sound, nothing.

After turning the power back on to the unit (after cleaning), it did go through the brief start-up purge cycle.

No error codes. Read out says 77 or 79, more or less.

What else should I be checking/cleaning? not sure what the standard setup codes are for this guy (manual is rather useless). Or is this obviously an electrical issue? Thermostat communication issue (that thing is old)?

Pics attached of my setup (keep in mind there is a 2nd boiler to the left of this one for the upstairs flat; lots of confusing pipes/etc).

TIA for your advice.

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Old 09-06-16, 12:54 PM
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NJT was the forum pro here. Unfortunately he is no longer on the site.

I'm not the boiler pro. I'm going to have to reread this thread to get back up to speed.

I seem to remember we were working towards an outside sensor that may keep the boiler from firing when it's warm outside.
 
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Old 09-11-16, 06:12 AM
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I am thinking your outdoor sensor may be keeping the boiler from firing...press and hold for 3-4 seconds the s4/reset button, it should show you d1 and then alternate with a number representing the boiler outlet temperature. Keep pressing s4 untill you get to d5, that will give you the outdoor temperature...let us know what that number is compared to an actual temperature out side, even from the weather channel...Just looking at the second from last picture posted shows a connection to two light green wires coming out of boiler..these should go to your outdoor temperatire sensor mounted on the north facing wall of the house(outside of course).
 
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Old 09-11-16, 03:18 PM
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Excellent poorplmbr, thanks for the information and explicit directions. Much appreciated. Will check this later this week when I am back from vacation.
 
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Old 09-15-16, 09:58 AM
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checked the temp on d5....

Ok, cycled through the settings - outdoor temp sensor d5 said 73. It is about that outside. :/

Any other thoughts appreciated...
 
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Old 09-17-16, 07:16 AM
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So that tells me your outside sensor is working,good. Now you need to see what your outside shut off is set to.I normally set them to 70*, yours may be set to the factory default of 68*. What this does is to tell the boiler not to come on, to make heat, if the temperture is at or above the setting. Pages 11 and 12 of your manual tell you how to get into, and adjust your settings...pretty self explanatory from there. Let us know what you find, and the outcome.( PS item 7 is your outside shutoff temperature)
 
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Old 09-17-16, 11:55 AM
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Hey there again - thanks for the help poorplmbr and talking me through this! Funny how the manual is making a bit more sense now with someone to walk me through it.

Went through and checked all the functions and default values - they are as they should be as per the manual default settings. d7 (warm-weather shut off) was at 68. For kicks I upped this number to above the outdoor temp (it's quite warm here today), powered the thing down and restarted (started up w/ the usual purge cycle). Cranked the thermostat and... nothing.

Reset the d7 Function to 70.

..........? any other thoughts? TIA
 
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Old 09-18-16, 09:00 AM
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Hmmm.... So the unit is not even attempting to fire? Try jumping out the thermostat wires (after you raise the warm weather shut down). I believe they are the two grey ones in the same spot where I see the green ones..You wont get a shock as they are 24 volt...lemme know...(At this point I am thinking thermostat or wires)
 
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Old 09-20-16, 05:38 PM
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wires all seem ok

Hi again,

Tested continuity for all the wires (green, gray, aslo at thermostat - only 2 wires there for This Old House). All were good.

Even bought a new thermostat "just in case" and installed that... nothing. However w/ the new thermostats there's a R, W, and Y markings for wires - only 2 wires here as stated above, put them in R and W and then switched them in W and R, still nothing. Am I correct that the Y is not needed here, or not...?

That said, if it's not the therm or wires, must be something with the boiler itself I'm missing. Argh!

Thanks again!

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Old 09-21-16, 04:59 PM
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Munchkin

I would still like to see if the boiler fires without being connected to the thermostat or wires.. disconnect the thermostat wires from the grey wires at the boiler and then twist the two greys together..see if that fires the boiler, again , make sure the warm weather shut off is set higher than the outside temperature. I have had an instance where continuity rang true but there still was a wiring issue..just humor me ..lol
 

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Old 09-22-16, 05:56 PM
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Just reading your post again..you said you tested continuity at grey, green , and thermostat. How exactly are you testing? You can only really test the wires themselves, they need to be disconnected from the stat and from the boiler to test...if you are testing with them attached to the boiler you are not going to get a reading that is correct.
 
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Old 09-22-16, 06:58 PM
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Welll sheeeee-it.... yeah they're still attached. LOL! can you tell I am NOT an electrician...?!?

Will try disconnecting the wires as suggested in your earlier post. Is it advisable to do this to all connections (green, at therm, etc?)
 
 

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