Munchkin 199MLP R1 not heating

PartieHonteuse

Hello Everyone,



While doing research I came across this site and unfortunately due to my research turning up really no results I decided to go ahead and post.



I have a Munchkin unit (see post title) that is suddenly not heating the water (gauge shows ~75) and sounds like it's running or doing something which I never noticed before.



Either way - looking at the controller I don't see an error code but what looks to be a display of "nc" (see attachment).  Sadly I'm not sure which product literature I'm to be looking at as this is all new to me and the product has been retired.  From what I can tell it either means D5 is not connected or the boiler isn't connected to the bus.  Either way, I can assure you that nothing has changed electrically in the house since last night.



I'm pretty handy when it comes to electronics etc (IT Director) but if you believe it's more than just replacing a simple part and requires complete tear down of the system could someone provide a good residential HVAC company in the Attleboro or Seekonk, MA area that would be able to service?



Thank you,



-Mike

kcopp

That is a internal processor...

error. Either the voltage is wrong or the neutral going to the boiler is broken/ damaged.

PartieHonteuse

Thank you...

kcopp, for the response.



I hate to sound dense but I have to ask to make sure I understand this...



"This is a internal processor" - i'm assuming you mean the controller board processor?



..."going to the boiler is broken/ damaged."  - Is it possible to elaborate on this on a little more?



I consider the "Boiler" to be the entire unit - including circuit boards and their connectors.  Should I assume that you mean that any of the 3 neutral connections (that i can see on the wiring diagram connecting to X4, X6, and X6 block on the controller board) are a possible error point?  Or do you specifically mean the neutral line coming from my main home electrical panel into the junction box attached to the outside of the boiler housing and going into the X6 block on the controller board?



Thank you again,



-Mike

Rich_49

Location

Mike , where are you located ? Could you post the serial number of the boiler ? 

PartieHonteuse

Requested info

Hi Rich,



I'm in Attleboro, MA



S/n: L07K1425



Thank you,



Mike

Rich_49

HTP

East Freetown Mass .  Contact them to find a local authorized contractor .  The control module and display if needed are what I would consider inexpensive if in fact none of the earlier mentioned items are the culprit . 

PartieHonteuse

yeah...

Already planned on giving them a call on Monday seeing as how they are closed on the weekends.  Was just hoping to find a solution before then.  Having a 7month old an no hot water is proving....interesting.



-Mike

Rich_49

Blog

portion of their site may get you a lead on local knowledgeable contractor , site has been evolving regularly but you should be able to locate the blog . Jason A is very responsive as long as I have been involved using their products (quite awhile) . Give that a try  

PartieHonteuse

Well that was fun..

Update and more questions.



I found a local technician that came out and found that the controller went bad.



I have a curious question though - does anyone have an image of the back of the 925 (not 926) controller?  The solder side not component side.  I've tried Google searching but came up with either only the 926 or just the component side of the 925.



Would be even better if someone knew of a replacement transformer part # from digikey or the link.



Thanks again.



-Mike

Rich_49

New board

Those Munchkins with the 925s are serial number specific . Not sure but don't believe what you are thinking is worth the effort . You can probably have a board and be enjoying hot water before all the research

PartieHonteuse

Not what you're thinking

Oh don't worry I already have hot water and a new controller. I was inferring that on my previous post. Got a 926 now.



The questions above are for my own knowledge. I get that the boards are programmed but I doubt the transformer issue (assumption) caused the board to erase the programming from the IC.