Buderus or Weil-McLainin Gas Boiler - Which to Buy?

johnxyzApril 15, 2008

We are going to replace an (ancient) oil-fired boiler with a gas fired boiler for basebord hydronic heating in a 1940's Colonial in the Northeast.

Which brand would you recommend:

Buderus GC124/4 SP or Weil McLain CGa-SPD?

I am leaning toward the Buderus because of perceived higher European quality.

But more techs may be familiar w/. the Weil McLain as well as easier sourcing of parts.

The Buderus is slightly more expensisve in the pricing quotes I have received.


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Buderus hands down between the two.
Have you looked at the Triangle Tube Prestige boiler? Much better boiler and value than both.

(Cast Aluminum boiler blocks haven't proven so well, search weil mclain failures, there are many.

Prestige is Stainless

    Bookmark   April 15, 2008 at 4:01PM
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Thanks for the prompt reply. I'll check into pricing for a Triangle Tube as well.

Weil-McLain really seems to be pushed - kinda like the GM or Ford of boilers. Are any of the Weil-McLain residential models gas-fired boilers cast iron?

Burnham, Goodman and several other domestic brands of questionable quality have all been mentioned by local dealers/installers. Must be comfortable with the US brands....

    Bookmark   April 15, 2008 at 4:33PM
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Weil Mclain has a number of cast iron gas boilers. My new GV3 is one of them. I thought the CGa and CGi were, also. The Ultra is their aluminum model, and I wouldn't trust aluminum, either. Stainless sounds much more reliable than aluminum. My GV was more expensive than the CG series, but is more efficient. I also had an Outdoor Reset module added to it. Even though a cast iron boiler shouldn't run below a certain temperature, the Outdoor Rest module helps save fuel.

    Bookmark   April 16, 2008 at 3:01AM
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Thanks - Yes on the Weil-McLain site the description of the CGa model is cast iron (not alum.). Not interested in the WM Ultra models.

The stainless steel of course is superior but the Triangle Tube models seem to cost double of the cast iron Buderus or Weil-McLain. Too much Mercedes/BMW pricing for me at this time.

of the US domestic brands for a gas-fired boilers (standard efficiency, atmospheric venting up a chimney)would you recommend:


Thanks again.

    Bookmark   April 16, 2008 at 9:04AM
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The only reason that Triangle Tube costs more is the features, your comparing it against cast iron models.

Hold it against the price of a W/M Ultra for the real sticker shock.

Outdoor reset is great however on cast iron models, provisions must be made to recirc water to control block temp with minimum return temps, like 130-140.

The more expensive modulating and condensing boilers love cold water, the colder the return water, the more efficient. It's not unheard of to heat your house on a mild day with 95 degree boiler water.

Why heat the water up to 140-180 to satisfy mama's chill on a 55 degree day?

    Bookmark   April 16, 2008 at 10:05AM
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Johnxyz: I've lived in a house with a Burnham, and that thing took a serious punishment and kept going. It was kept in a detached, unheated garage with a roof that leaked more than not having a roof. It heated an 850 sq ft single story house built in 1948. Both Weil-McLain and Burnham are decent products.

zl700: I couldn't agree more. My GV boiler has a built-in bypass circulator to prevent shock to the sections. However, I still have my minimum 'reset' water temperature at 140°. It was my understanding that having the water be cooler, even though the boiler can mix hot with cold on its own, would create more condensation in the combustion chamber than the design could handle over the expected lifetime. Perhaps I'm over-analyzing it, though. When first installed the boiler was operating around 120°, which I thought was too low for cast iron. What's your take?

    Bookmark   April 16, 2008 at 10:02PM
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The GV was one of the first boilers to cross over the 84-85% AFUE which put it in the condensing range. Yes W/M put a circ in the boiler to combat that but they also added a temp mix/bypass valve in conjunction with it.

So feel free to dial that outdoor reset lower. Depending on how your boiler is piped, primary/secondary (which is best) you could use the boiler circ to inject heat into secondary heating loop(s) and appreciate even lower water temps. Without primary/secondary you must be careful to not cycle the boiler to much when operating in the lower temps (small trade off).

I'm hoping this boiler was installed after the plexvent problem or has been upgraded since to Cat II Stainless, right?

My personal take on the plexvent issue, it was brought on by improper installation, sealing, lack of support, improper cutting, and using non-UV fitings outside.

Aside from that it's tough to screw up gasketed stainless pipe with clamps.

    Bookmark   April 16, 2008 at 11:00PM
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I just looked at the Primary / Secondary concept, and this is not what my system is using. My GV was installed in October to replace the original 25 year old atmospheric boiler (of twice the BTU rating).

When the boiler was operating in the 120° ~ 140° range, it was, in my opinion, short cycling. I guess this is because it's not modulating. It just spits out 70k BTU's of heat to bump the water temp and then stops.

The vent used is a clamped stainless type. It's just over six months old. I've not heard of the PlexVent issue. Did they rust?

Maybe when spring arrives (if that will EVER happen this year) I'll get to see how the system behaves as the weather warms in regards to short cycling, etc.

    Bookmark   April 17, 2008 at 12:35AM
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Plexvent was a high temp plastic venting material that broke, cracked & leaked at joints. In addition when non outdoor ftgs were used outside, UV rays broke down the tee or ell and it fell off allowing the vent pipe to fall into the house thus, venting inside.

Again, proper and skilled installs never had a problem with this but it wasn't as fool-proof as SS so, the advocates went after them.

Primary/secondary would be something I would strongly consider for your boiler combined with the lower/wider reset curve. If you have cast iron radiation, all the more reason to better your system this way.

    Bookmark   April 17, 2008 at 9:52AM
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So would the consesus be to buy the Buderus GC 124/4 SP gas-fired boiler over the Weil McLain CGa? Any votes for the Weil-McLain CGa?

Last call - Thanks

    Bookmark   April 25, 2008 at 3:47PM
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