Monitor mz

Brad White_9

and agree with Mike and Alan's assessment. Mine is in the middle of it's third season.

Good, solid and stable, wide water and gas passages but no modulation.

94.5 MBH input and about 89 MBH output versus my house load at about 55,000 BTUH. Sure it is low-mass but the short cycling was annoying.

My first year gas usage was about the same as my Burnham 204 with Centra 4-way mixing valve which I had since 1986 or so.

I added OD reset (from MPI and made by Tekmar) and a return side buffer tank and it is now more stable but still cycles too much for my taste.

Pete Caruso at MPI tells me that a modulating version is in the works.

With the boiler as it is now, if my heating load were higher I would be happy with it. It comes in one size though. Would I recommend it? Not without modulation. On-Off is so, like, last week! :)

jp_8

monitor mz

has anyone had experience with the mz boiler from monitor? must customer found them on the web and wants one badly. any info would help.

Mike T., Swampeast MO

Pros report that they are simple, efficient and extremely reliable saying things like, "The only condensing boiler I'll install away from my general service area". Only negative seems to be the inability to modulate the burner.

Alan(CaliforniaRadiant)Forbes

We've installed

six of them and they're all working fine; very stable.

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soot_seeker_2

A rare instance

This is probably one of those rare instances where you may be have been better off with the even more oversizede MZ 40 model since it works as a two stage 70/140 input based on return temps. If the delta-T is too great I wonder if it can be easily tricked or persuaded to use a wider DT before firing on both sides?

Brad White_9

Thought of that once

but even so it would still run steady state only on a design day. I would have two burners at least and all that surface area, so some merit.

Delta T averages 25-30F on the radiation (cycling makes it harder to predict or remain steady).

My primary flow is 5.5 GPM through the MZ (B&G visual flow meter) and runs about 32 degrees Delta-T on the boiler side. If I could get more flow through the boiler I would, but it is at maximum now.

With the OD reset my differential is about 15 degrees. Less than that it cycles, more than that, the HWS line temperature swings too much.

Thanks for the thoughts, though.