WM97+ High Altitude question

[Bart56]

Hi All,

I had a Weil Mclean WM97+ NG boiler installed in 2013. When the contractor installed it, I noticed it was a model 155 when he quoted a 110. When I asked him about it, he told me that was what the distributor gave him and went into settings and set it to WM97+ 110. There was quite a bit of hassle trying to get it to fire up quietly (often had a loud Boom). So he called in the regional WM tech person. After fiddling with it for an hour or so, they ordered a new igniter which was installed a week later.
Ever since then, it often 'booms' when firing up. I cleaned the igniter and it quiets down for a while but still either makes a 'boom' or a slow growling start. The flame looks good after it starts - nice and blue with orange speckles on the walls of the chamber.

So I'm thinking about getting annual maintenance and my contractor is no longer in business. So I snoop around the settings and I find that it has been set to 110HA which is a high altitude setting. My house is at about 300' above sea level elevation. Also, it only needs less than the 100K BTU output of the 110 but now I wonder if this HA setting (and other settings like purge time, etc.) may be causing some of the firing up issues.

So my questions are: Does setting the digital "High Altitude" Yes/No setting to Yes change the gas flow rate or just the air flow rate?
I don't know if my contractor was trained by Weil Mclean - I'm guessing not - but how important is it? If I call a random contractor, I feel I face the same issue.
I went on the Weil Mclean website and used "locate a contractor' page and no one closer than 20-25 miles away shows up (So central MA).

Are there any "trained by WM" contractors out there or are they just HVAC GC's that got listed? Do Trained WM contractors follow the service manual when doing annual maintenance service or do they just do what they think is correct?

The last HVAC contractor that I called for my old boiler to clean and tune it showed up without his flue meter equipment and said he would have to charge me again to come back and measure it so I'm a little concerned about who will do it.

Thanks for any advice

Bart

[Special-K]

Moved to AOP

[heatingman]

I think it may effect the light off fan speed and as a consequence may be part of the issue.

In any case it sounds like a set up issue, either software or more mechanical with gas pressure settings and so forth.

Light off should not be aggressive.

I would reach out to Weil Mclain directly and ask for a preferred vendor in your area.

I would also include the issues you have been having in your correspondence.

Its been a long time since I worked on one with regularity so I cant really be more specific.


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[Bart56]

Thanks @heatingman
The WM Locate a contractor results showed about 7 contractors - at least 25 or more miles away. Unfortunately, none had the "preferred" label.

[heatingman]

Thanks @heatingman
The WM Locate a contractor results showed about 7 contractors - at least 25 or more miles away. Unfortunately, none had the "preferred" label.

Im not sure the listing would show “preferred” or not.

But without a doubt - if you reach out directly and make enough noise, they will find you someone that can resolve the problem.

Might even try somewhere like Facebook if they have a presence there.

May get the attention of the right people.

Best of luck.

Another good resource might be Heatinghelp.com

Lots of boiler guys there.


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[Bart56]

The Locate a Contractor page has badges for each contractor
Preferred ContractorPreferred
Contractor NATE Certified NATE
Certified Spanish Speaking Técnicos hablan Español
Financing Available Financing Available Bonded and
Insured Bonded and Insured

The highest in my area was NATE certified. I guess the question becomes what is a WM Preferred contractor?
Back in the day, manufacturers used to put on training classes for their systems. Once taken, we became the local/regional tech support folks for that system. (I did Honeywell, IBM, NCR, DG and others and went on to teaching regional classes as needed.)
I was thinking that WM did the same training but WM Preferred may be a marketing classification not a technical one.
Thanks for the advice. I'll check out heatinghelp.com

[kangaroogod]

You need to find a tech knowledgeable with a combustion analyser, intuitive, familure with wm and capable of speaking with tech support. It is likely a gas/air adjustment or an installation deficiency such as improper venting that will need some time to identify and resolve

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[Bart56]

Thanks kangaroogod.
Weil Mclain was kind enough to tell me that a contractor could call their tech support. I've also found from WM Support that "preferred Contractor" is any contractor that asks to be on their Preferred list. I thought it was a qualification but i was wrong.

I can find techs that know how to use a combustion analyzer, but was hoping to find someone with WM expertise too. Sadly, this may not be available.
Cheers

[kangaroogod]

Thanks kangaroogod.
Weil Mclain was kind enough to tell me that a contractor could call their tech support. I've also found from WM Support that "preferred Contractor" is any contractor that asks to be on their Preferred list. I thought it was a qualification but i was wrong.

I can find techs that know how to use a combustion analyzer, but was hoping to find someone with WM expertise too. Sadly, this may not be available.
Cheers

Wish I was closer to ya. Good luck

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[Bart56]

Thanks kangaroogod.
We're only about 350 miles apart...

I'm assuming you have WM experience so let me ask you this.

If you installed a WM97+ 155 in a house that only needed 100K BTU, would you set the boiler model in the control panel to model 110 in hopes of reducing the input/output BTUs? I've read the manual several times and it says to make sure the model number is set to the stamped name plate on the unit. My model 155 is set to model 110 High Altitude (when I'm at 300 or so ft elevation).

I'm going to write down all the firing rate information in the settings to see what it's really doing when it fires in hopes of determining my next step. I found a local tech that services several neighbor's Boderus condensing boilers and he feels sure his techs could service my WM. I'm concerned that the nuances of the model settings vs output may not be interpreted easily by an untrained individual. Can you ease my feelings on this?

Thanks.

[pecmsg]

I know of no magical switch that can derate a boiler! That boiler is rated for 155K btus and will try and deliver that, or waste fuel trying.

300' is not high altitude.

[Bart56]

Makes sense to me pecmsg
Since it is a modulating burner, do you think putting it back to correct settings is a good idea? The unit is apparently sized incorrectly for my heating demands so it's probably not giving me the best efficiency no matter what I do. I'm making the assumption that the correct settings for a 155 may be more efficient than the current attempted derating settings. The thing that gets me is that WM tech support was brought in on the initial install and this is how it was left, but they won't talk to me.

[pecmsg]

Makes sense to me pecmsg
Since it is a modulating burner, do you think putting it back to correct settings is a good idea? The unit is apparently sized incorrectly for my heating demands so it's probably not giving me the best efficiency no matter what I do. I'm making the assumption that the correct settings for a 155 may be more efficient than the current attempted derating settings. The thing that gets me is that WM tech support was brought in on the initial install and this is how it was left, but they won't talk to me.

You need a Combustion Analysis performed before and after adjustments are made.

Bottom line that unit has been abused for 8 years now. Get a properly sized and installed boiler!

[kangaroogod]

Thanks kangaroogod.
We're only about 350 miles apart...

I'm assuming you have WM experience so let me ask you this.

If you installed a WM97+ 155 in a house that only needed 100K BTU, would you set the boiler model in the control panel to model 110 in hopes of reducing the input/output BTUs? I've read the manual several times and it says to make sure the model number is set to the stamped name plate on the unit. My model 155 is set to model 110 High Altitude (when I'm at 300 or so ft elevation).

I'm going to write down all the firing rate information in the settings to see what it's really doing when it fires in hopes of determining my next step. I found a local tech that services several neighbor's Boderus condensing boilers and he feels sure his techs could service my WM. I'm concerned that the nuances of the model settings vs output may not be interpreted easily by an untrained individual. Can you ease my feelings on this?

Thanks.

This is treading into diy territory but I dare say the following is allowed as it is published in the manual and is generic info.

The model selection change has less to do with input and more to do with the draft inducer operation as does the high altitude adjustment. Setting this improperly may cause unsafe operation as it can change the gas/air mixture.

The boiler needs to have the proper gallons per minute flowing through it and a larger boiler will require more than the smaller one. Piping design is very critical as well.

Refer to my previous post for my suggestion

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[Bart56]

This is treading into diy territory but I dare say the following is allowed as it is published in the manual and is generic info.

The model selection change has less to do with input and more to do with the draft inducer operation as does the high altitude adjustment. Setting this improperly may cause unsafe operation as it can change the gas/air mixture.

The boiler needs to have the proper gallons per minute flowing through it and a larger boiler will require more than the smaller one. Piping design is very critical as well.

Refer to my previous post for my suggestion

Thanks again kangaroogod.
Now I wish you lived closer too.
I have 3 zones plus DHW priority set up. After doing a heat load calculation I realize that running as a 155 is oversized. It seems to handle the call for hot water ok. When my smallest heating zone calls the burner modulates ok too and it seems like I get plenty of condensate, so I'm hoping a local experienced tech can make sense of the WM controls. Maybe I'll put in more baseboard fin tube as well to help compensate. Might as well stay warmer if it's being wasted.

I know that Weil Mclain corporate tech support was helping the original contractor and local WM expert because I have his direct number still on the worksheets used when setting it up. I might just call that number to see if he's still there. But I'm hearing you on finding a local tech to do the combustion analysis and set it up all over again. (I don't have a few grand to junk this one and get a smaller one to replace it.)

Oh - one thing I noticed during inspection is that the flue sensor near the bottom of the flue pipe is just stuck into a hole in the pipe by friction with a little orange foam gasket around it. It simply slides out by hand and I thought it would be more mechanically affixed. I don't see it in the parts diagrams but does this match your experience?

You've been a great help - thank you.

[kangaroogod]

Thanks again kangaroogod.
Now I wish you lived closer too.
I have 3 zones plus DHW priority set up. After doing a heat load calculation I realize that running as a 155 is oversized. It seems to handle the call for hot water ok. When my smallest heating zone calls the burner modulates ok too and it seems like I get plenty of condensate, so I'm hoping a local experienced tech can make sense of the WM controls. Maybe I'll put in more baseboard fin tube as well to help compensate. Might as well stay warmer if it's being wasted.

I know that Weil Mclain corporate tech support was helping the original contractor and local WM expert because I have his direct number still on the worksheets used when setting it up. I might just call that number to see if he's still there. But I'm hearing you on finding a local tech to do the combustion analysis and set it up all over again. (I don't have a few grand to junk this one and get a smaller one to replace it.)

Oh - one thing I noticed during inspection is that the flue sensor near the bottom of the flue pipe is just stuck into a hole in the pipe by friction with a little orange foam gasket around it. It simply slides out by hand and I thought it would be more mechanically affixed. I don't see it in the parts diagrams but does this match your experience?

You've been a great help - thank you.

The flue temperature sensor is press fit into the stainless with a high temp rubber and is a friction fit. It is likely the rubber has contracted some and the fit is not as snug as new.

The boiler should be piped in a "primary/secondary" design to allow adequate flow at all times through the boiler regardless of how many zones are calling. The piping would typically be 1" or larger for the 105 and 11/4" for the 155. The circulator for the 105 would be a taco model 007 and the 155 would require the larger taco model 014.

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[Bart56]

Yes. The main pipe is 1-1/4 to the 3 zone pumps and 1" to the DWH. All the returns go into a 1-1/4 pipe. Both the input and output pipes are in a sort of manifold configuration where the loops begin and end. The loops themselves are 3/4". Taco pumps for each loop but I didn't see which model they were but I'll check.

Thanks for the clarification on the flue temp sensor. I finally found the reference to it where it says to pull it out and insert the combustion analyzer into the hole. The parts diagram simply shows it separately so I missed it earlier.

And to your point about DIY territory, I'm fully capable of cleaning it (I used to clean my old boiler all the time). But I don't have the tools/skills to do the combustion analysis. Therefore, the qualified tech need.
Cheers and thanks.

[Bart56]

The boiler should be piped in a "primary/secondary" design to allow adequate flow at all times through the boiler regardless of how many zones are calling. The piping would typically be 1" or larger for the 105 and 11/4" for the 155. The circulator for the 105 would be a taco model 007 and the 155 would require the larger taco model 014.

Just to clarify - you're saying that the primary/secondary design is recommended. My 155 has an internal Primary/Secondary bypass valve which is is open so I think that meets your suggested primary/secondary configuration. I'm not sure what it does for Delta T if only one zone is calling but I'm guessing it's pretty small given the primary loop is very short. I guess more importantly is that the fuel/air ratios are set properly for a good startup and running. Efficiency may be in question if the DeltaT is too low but my concern is the proper and safe boiler operation.
You've helped me understand a lot more about my system and I am grateful for your advice.
Cheers

[pecmsg]

Just to clarify - you're saying that the primary/secondary design is recommended. My 155 has an internal Primary/Secondary bypass valve which is is open so I think that meets your suggested primary/secondary configuration. I'm not sure what it does for Delta T if only one zone is calling but I'm guessing it's pretty small given the primary loop is very short. I guess more importantly is that the fuel/air ratios are set properly for a good startup and running. Efficiency may be in question if the DeltaT is too low but my concern is the proper and safe boiler operation.
You've helped me understand a lot more about my system and I am grateful for your advice.
Cheers

And thats a valid concern.

How often does that unit cycle? 5 minuets on 10 off?

Efficiency is achieved after about 10 - 15 minuets run time. You have a boiler thats what 40+% oversized and making matters worse is Zoning. That internal bypass is not enough, you need a properly sized boiler with a Buffer tank to handle those light loads as needed.

[kangaroogod]

Here's the rub with high efficiency systems. A "condensing boiler" will be more efficient when the flue gas condenses back to water. This will extract more heat out of the outgoing exhaust gasses BUT this only occurs with a return water temperature below 140⁰ +/-. When a system starts up and everything is cold it will condense and be very efficient. When you are running radiant heat with a return water <140⁰ the boiler loves it and condenses like crazy. However, in a high temperature application such as baseboard, unless you are using an outdoor sensor to lower the supply temperature to <150⁰ the boiler will only condense for a very few minutes out of the hour typically.
When a boiler is oversized and even worse oversized when zoned, the minimum firing rate often exceeds the system /zone capacity and the unit almost never condenses unless an outdoor sensor is used and even then the boiler is off and on with less opportunity to condense. Typically I see around a 87% efficiency on condensing boilers in high temp applications.
The industry has done well in marketing high efficiency but poor in education.

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