can Munchkin max/min output be adjusted?

R. Kalia

I know it's a modulating boiler. The model in question is variable from 199,000 to 67,000 BTU. Now we will never need more than 150BTU. Can the burners be adjusted to derate them by 25%? The contractor says yes, but I don't see anything about that in the literature. (I know it can be done for some Lochinvars, but these are not modulating.)

Explanation: if there is an adjustment that derates the burner, it will reduce both the maximum and minimum. The maximum limit doesn't matter because if only 150,000 BTU is needed, it can do 150,000BTU. But the minimum DOES matter, because it can't go lower and so on warmer days we'll be back to on/off rather than modulated operation. If the minimum BTU can be reduced, we'd be on modulation for a larger part of the season.

If this can be done, are there risks like increased CO or voiding the warranty?

Guy_5

Modulation

There is no way to safely change the output of the Munchkin. The great thing about being fully modulating is that it will only run at a rate that is necessary. In the odd occurence that you might need the extra heat, the BTUs are there.

R. Kalia

OK

OK, thanks for the reply! But I should point out that I was talking about the minimum limit---the Munchkins do not vary all the way to zero, of course, so the lower the better. The 'T' models seem to have 1:5 modulation while the others do only a factor of 3. Your brochure does not explain what the T models are.

jalcoplumb_2

The boiler does..

modulate to 67000 as you pointed out. Will you be using a vision system? How well was the heatloss done? I see a lot of systems that could have gone w/ the 140 vs the 199 due to a simple heatloss error. How cold does it normally get in your area?

It would cost more but you could use two smaller munchkins with the vision 3 system. The smaller units have a better modulation ratio and are wall hung. This would keep you modulating well below the 67000 mark.

The other thing to keep in mind is that the munchkin is 92% through the whole modulation range. Even though it might cycle a bit on the warm days it will still be running at 92%.

I would not try to derate it. Why does your contractor think it is OK? Is he OK?

Good Luck,

chuck shaw

T-Models

are wall hung. There is the T-50M or the T-80M.

Hope this helps.

Chuck Shaw
Technical Support Department, Heat Transfer Products

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R. Kalia

I understand that, but...

I actually did know that. What I wanted to know is, what is the difference that causes the T models to have a different modulation range? Now maybe it is obvious to an expert that "A wall-mounted model can of course have 5-fold modulation, but a floor model can only do a factor of 3", but it is not clear to me as a homeowner!

Ken_8

The 'T' models...

Start the wall smoldering and will then turn off - allowing heat to continue at approx 1:5 modulation of full fire.

There being no wall to catch on fire on the "floor-mounted" units, they can only do 3:1

Kidding of course! Excuse me now. I need to take my medication

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R. Kalia

what about the AFUE?

> Start the wall smoldering and will then turn off

> - allowing heat to continue at approx 1:5

> modulation of full fire.


This can't be true, because it would increase the AFUE to above 100%.

ScottMP

Keeeeennnnn

Stop it now...

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