Weil Mclain

Matt_17

I have two questions: First,Is the weil mclain CG gas boiler (direct vent) a condensing boiler? Second, Is this boiler a good choice for a monofol T system with high return water temps?

Ken_8

Here's the answers...

First, no. None of the W/M CG direct vent models condense.

Second, yes. It is a good choice for monoflow T systems - as long as the circulator is pumping away from the point of no pressure change (the expansion tank).

Without the pump being located in the "pumping away" location, you'll be bleeding the convectors/radiation every season - at best!

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Floyd_5

Ken, you are right.....except for...

WM does make a direct vent condensing boiler....
The Ultra boiler IS a direct vent condensing boiler....
And a very good one at that......
It can also be run at high water temps. but the eff. will be lower....but still higher than most anything else out there.
The CGs is a good choice for a basic low cost boiler.

Robert O'Connor_7

W/M CG

I think the CG is the atmospheric boiler (not direct vent) I think the CGi (with the fan) will go both chimney & direct. The Ultra is the direct vent & condensing. All will work. It depends on the efficiency you desire and the $$ your willing to part with. My personal thought about the choice in a monoflo system aplication would be the CG, It's been out there the longest & has the better track record for reliability, a little down on the efficency but a real workhorse... Robert O'Connor/NJ

Ken_8

Yeah but...

The question was not about the Ultra. It was the CG. The CG comes in four models. The CGs (sealed combustion - direct vented (no chimney required)); the CGi is also direct vented (no chimney required); the CGa, which does require a chimney; and the CGt, which can either be direct vented - or chimney vented - and comes with a built in tankless coil.

W/M makes a whole bunch of similar gas fired units, the Ultra being just one. The AHE, GV and PFG are also fine boilers - in the residential water boiler lines. Each one has its own price/performance/size reasons for existing.

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Al Letellier

W/M gas

Why not a GV and hook it up P/S.? Works absolutely great, is condensing and probably the highest efficiency except for the Ultra. And it's direct vent.

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R. Kalia

not true

> Why not a GV and hook it up P/S.? Works

> absolutely great, is condensing...


Not correct.

Ed_13

Weil-Mclain GV verus an Ultra

It is my understanding that the Ultra is Weil-Mclain's only "condensing" boiler. The GV is a high efficiency direct vent boiler, but it is not a condensing boiler.

Paul Mitchell

Correct

But the GV may have some condensation form in the flue I think that is where the confusion is. Unless you jump to the ultra...the efficiency rating is no big deal.. I think 87% on the GV and 85% on the CGI

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Al Letellier

GV

My mistake on the GV being condensing, but I would still use in on this kind of system. Best WM bet in my book and we put in a lot of them.

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Ed_13

GV

Another nice feature of the GV is it's self protection regarding cool return water. Internally, there is a taco 007 on the return and a taco 007 as an injector pump. Both are computer controlled and work with an external bypass to assure the water returning to the block is hot while the actual load return may be cool. I have a GV feeding a high mass radiant slab with an indirect water heater. Very happy with it.