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Dunkirk / ECR International MOd Con blowing internal fuses after power surge

Hi, I have a Dunkirk (ECR) DCC205 that has been running great 15-20 delta T (thanks to you guys), no problems this season until a fallen tree snapped my neutral line at the pole and caused a massive surge, blew a bunch of bulbs and had to replace several breakers. After power was restored I noticed that the boiler was 'off' / control panel blank. Also no lights on the Taco circulator relay (SR502-4). There is 2 little glass 3.15 fuses inside boiler that were blown. Went to hardware store and replaced and both fuses blow as soon as I plug the boiler plug (120v) into wall outlet. I tested the outlet with a 3 light tester from Lowes and shows 'good'. I unplugged all the connections to the mother board except the 120v what is labed as L N G and fuses blow instantly as before. I'm thinking that the circuit board has some sort of short circuit, maybee at the little transformer that is on the board.

The Taco switching relay is bad too but its easily replaceable

I'm waiting for an independent heating contractor that I used before (the good ones are all busy this time of year LOL) just to let someone more qualified hopefully make a diagnosis. The gas supplier tech that showed up is convinced that I need a whole new system even though mine is 3-4 years old and literally looks brand new still.

My question is can one of the 120v operated items that are in the the boiler controlled by the circuit board / mother board also be shorted . I'm afraid of installing a new board and having it be damaged too by another component like the primary pump or inducer fan.

I attached a bunch of files for reference



  • 109A_5
    109A_5 Member Posts: 1,387
    Hello @marsfromrexford,

    My question is can one of the 120v operated items that are in the the boiler controlled by the circuit board / mother board also be shorted . I'm afraid of installing a new board and having it be damaged too by another component like the primary pump or inducer fan.

    The other 120 VAC devices could be independently tested to see it they are good or not. If they act dead (no operation) and not shorted they still may work when a good board commands them to. Kind of depends on the device.

    The MOVs (surge suppressors) and maybe other components on the control board are probably shorted. Unless you can do that type of repair work or have a friend that does, you probably have a new control board in your future.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    EBEBRATT-Ed Member Posts: 15,613
    The supposed gas tech is an idiot. I would disconnect the pump and the fan motor one at a time and ohm them out and test them for grounds and also the transformer if possible.

    Was the fallen tree on your property or others?

    Either way you may be able to put in a claim with the electric utility. You would be surprised how much they pay out.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,053
    I would hazard a guess as to the condition of any 120 VAC item, that was operating at the time of the tree fall incident, is now trash. If there was a call for heat at the time of the incident, then the actual circuit boards inside the equipment are probably defective. The circulator motor(s) that were operating are smoked, the combustion fan is bad, and any transformers that convert 120VAC to 24VAC or any other control voltage are also gone for good.

    I would say that the labor to remove all those parts and replace them may actually come to more $$$ than a replacement boiler. Kind of like when the insurance company makes the decision to repair a car after an accident or to TOTAL LOSS the car.

    If it is going to cost more money to make the old one whole than it would cost to replace it, the choice is easy.

    I used to use Flat Rate pricing for service calls, If I were to take each individual part of a heating system individually and pull each one up on one invoice in order to build the heater from scratch one part at a time the total invoice for that job would be over 12 times the price of installing a heater that is already assembled rough out of the crate. That is because each and every part has a predetermined amount of labor included in the Flat Rate Repair price.

    Since the boiler block and the cover are probably not damaged, then there are several parts that “Look Brand New”, you may be able to keep them. That might drop the cost from 12 x higher down to 6 x higher. Still not something you want to do, Especially if you can get the homeowners insurance to pay for it.

    But, I’m sure that those good parts can be salvaged for future use. Put the damaged one in the box the new one comes in and save it. There may be a non-electric part that fails in 15 years, that no one has. But you will!

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    EBEBRATT-Ed Member Posts: 15,613

    Problem is when the neutral is broken/lost all 120volt loads in the house go in series and depending on the different resistances of the appliances and what is turned on and off some 120 volt loads may be subjected to 240 volts.......then the smoke is released.
  • marsfromrexford
    marsfromrexford Member Posts: 21
    Ed, that makes a lot of sense they way you put it, seems like what ever lights were on blew at the instance as well but obviously not a problem. Thankfully the range, cloths washer ect wasn't running / off at the time.

    Too bad the little internal fuses didn't offer the needed protection but then again it was a voltage spike not a current spike and that the glass fuses are rated at 250v

    I found a circuit board online, might roll the dice and get it coming, doubt I will find one locally