Weil McClain Evergreen Pro Boiler Line (299, 399, etc) vs Lochinvar Knight XL Opinions

rhasody

I'm trying to gain some insight on preferred high efficient boilers. This is for replacing an older cast iron boiler, that is vastly undersized for a large home with many radiators scattered throughout (cast iron). Given the size of the house, etc, it seems we'll be going with something geared to large residential or light commercial and not going down the route of cascading Naviens, etc.

Recently I'm hearing options for the Weil McClain Evergreen Pro line or the Lochinvar Knight XL. Obviously one is fire tube and one is water tube.

There seems to be some hate from some contractors on the Weil McClain (WM) Ultra (not evergreen pro) series and their aluminum heat exchangers, which seemed to cause a lot of issues. However some now claim the newer WM Evergreen (EVG) pro line is much improved with efficiencies and has stainless steel heat exchanger. Ive head some claim they're great when installed correctly. Do y'all agree? Any experience with them?

The Lochinvar Knight XL has a dedicated following as well. Any recommendations between the two?

Has WM worked all the bugs out of the EVG line now? Some show 95-96 AFUE ratings….
Any inherit benefit(s) to Lochinvar Knight XL?

Thanks for any insight.

Forgot to add, many radiators were removed by a previous homeowner to get the current undersized boiler to quasi "function". The old boiler only barely functions now as is much less doubling the number of radiators on it.

We also did a Heating load calc. Currently the boiler constantly runs. It cannot get the temp above 60-65 in the middle of winter for much of the house. We've gone through the exercise of account for room sizes, heights, windows, rads etc. No insulation in home, single pane windows. There is no doubt the boiler is undersized as is.

pecmsg

How do you know it’s vastly undersized?

That would be a 1st!

rhasody

…

rhasody

Many radiators were removed by a previous homeowner who went cheap on a boiler replacement. That old boiler has never been able to keep up with what is in the home, much less adding more radiators in to make up from all the ones he yanked out.

rhasody

https://forum.heatinghelp.com/discussion/comment/1870280#Comment_1870280

A first? Ever encounter a place where the previous homeowner did some shenanigans?

The question is not about whether it is undersized. Its about boiler brand experience and related opinions.

GGross

If my choices are WM or lochinvar I choose lochinvar. Wish you would accept some assistance on the rest of the the system though, there are a lot of experienced voices here, and I agree with @pecmsg I have personally never seen an undersized boiler on a job, underperforming systems, lack of emitters, for sure though!

Jamie Hall

Ah… folks, I've been there. At one point many moons ago someone had the bright idea of dividing Cedric's home in half, and only heating half of it. Fortunately, they didn't remove any of the radiation — just valved off half of the system. And installed a boiler to served the rest — which, oddly, was more or less the right size for the rest.

This created a lot of problems however, and the decision was made to heat the whole building, which led to the present setup (with a lot of help from Noel Murcough and @Charlie from wmass ).

But to our OPs question: it isn't so much the make of the boiler — both Weil-McClain and Lochinvar make very good equipment —it's the quality of the installation. Granted, hot water is easier in some ways than steam, but it's still possible to make mistakes. Look at the installer.

GGross

https://forum.heatinghelp.com/discussion/comment/1870311#Comment_1870311

Let's just say hypothetically that you HAVE to choose between the two manufacturers for a new mod/con install, both are correctly sized to the load and application, and the installer is familiar with both and does good work. Which do you choose?

pecmsg

the installer

pecmsg

Charlie from wmass

I prefer boilers that are made by the name they are sold under. Having said this I prefer the Lochinvar. Hot water and forced air systems are just as difficult to install as steam. The difference is steam cries louder when done wrong.

hot_rod

Sounds like the next step would be a radiation assessment. See how it matches the heat load number.

Ideally you will heat the home with supply at or below 140F all or most of the heating season. Try to leverage the condensing function.

I like Lochinvar as a company, their control, and support.

Some tips here.

https://www.caleffi.com/en-us/magazine/25-lowering-water-temperature-existing-hydronic-systems

rhasody

https://forum.heatinghelp.com/discussion/comment/1870309#Comment_1870309

Thank you for the perspective.

Yes, it defies logic. I hear you completely, why someone would put in a underrated boiler. Neighbors have explained the previous homeowner was a notorious tightwad, and had the current boiler put in as a DIY job, after he got the boiler on closeout. It was never the right size. He then had to disconnect many rads in the house to get it to even quasi function. He then sold off the disconnected rads. And when it gets cold the boiler can't even keep up with what we have now, much less adding back the missing rads to the loops. Some conditioned areas of the home are 39 degrees during the dead of winter. We have space heaters everywhere. He did a lot of other shenanigans around the house, that I'll spare you. Its beyond infuriating and mind boggling how someone could do this.

All that said, its not that I am shutting that side discussion on whether the boiler is undersized, but we've had numerous contractors work on the system, had heat loss calcs done on every room, had many thousands of work of work on the old boiler, loops and circulators and they all have the same takeaway—-the boiler is undersized and the only way to fix this is to GO UP in capacity.

This is not a rash decision. It has been a 5 year process, of seeing how the boiler behaves during the winter months trying to make it work with what we have and seeing it still struggles. Its still frigid in many areas of the home. Its about 9,500 sf of conditioned space served by a roughly a single 250,000 BTU (net) boiler in Michigan, with no insulation and single pane windows….) I've basically been told it needs to be doubled in capacity if not more to handle everything.

Lochinvar and WM are the two brands I keep hearing the most from the contractors. Id be open to other brands two, but these are the two that keep coming up that get us to about 95-96% high efficiency.

Sorry for the novel of a post. Its just a crazy situation here and I can't believe someone would do this.

rhasody

https://forum.heatinghelp.com/discussion/comment/1870320#Comment_1870320

Thank you. We had the radiation assessment done. That's when the numbers reinforced what our perceptions were in many rooms ITS TOO DANG COLD and why the heck did all these radiators just disappear.

I'm glad you mentioned the ~140 degree supply temp. That really does seem to be the way to get most efficient operation (regarding natural gas consumption) to get the condensing function working well. The undersized/ old boiler is a non condensing cast iron. I suspect its not very efficient given how often it stays on and doesn't keep up.

pecmsg

so your supplying 140* water to radiators designed for 180*?

rhasody

https://forum.heatinghelp.com/discussion/comment/1870328#Comment_1870328

That was a discussion on IF it was a high efficient boiler. Currently we do not have a efficient boiler.

hot_rod

At this point you need to work with the hand you were dealt. Connect a boiler that meets the heat load calculation number. Pipe it properly, good air removal, purge points. etc, etc.

Fire it up on ODR with design set at 180.

Does it heat adequately on the coldest, design day? If so, start cranking down the design supply temperature. Get it as low as possible to maintain your desired indoor temperature.

Enable the outdoor reset function and the boost feature.

Now if the system is grossly under-radiated, that will take a different solution.