Vissemann CM2 311 at 7,600 feet elevation

mars_6

Hello my fellow wallies, I have a new construction CM2 311 boiler installed that is providing snow melting for 6,500 sq ft of snow melt and DHW production as well as supplemental heat for a radiant floor heating system. at this point the system is only servicing the snow melt system we have not integrated it into the other systems it will be serving. this boiler was commissioned 4 weeks ago and ran fine for 3 snow events and then started tossing F9 and FD fault codes. i have 120 man hours trying to get this figured out. at this point i know that the gas pressure is where it needs to be the, the electrical requirements are where they need to be and the system pressure is where it needs to be. what i am seeing is a fault code F9 and Fd when I am at high fire? I down fired the CM2 to 80 percent and the unit will run. I am thinking i am getting flame lift off of the flame sensor. Has any one had this type of experience with this boiler? The boiler is piped primary secondary with the pumps and piping sized as needed. any thoughts would be helpfully. thanks Matt

CMadatMe

It's a fan issue. Bad cable or the burner control itself. Make sure your derate adjustments are correct. Suggest you call the Tech Line 888-484-8643.

Zman

Matt,
I have no experience with that unit.
A quick look at the service manual points in the direction of a fan issue.
Have you talked with tech support?
How is the combustion?
How long are the exhaust vent runs?
Pressure switch?
Carl

CMadatMe

He reduced the max high end of the modulation % more then likely below the requirement for his altitude, thus why its running happy at 80% max. When he goes to 100% it won't and shouldn't run happy because he's not under the 1000' elevation threshold for 100% max output. Boiler is acting properly. He needs to make sure his derate % is correct for his altitude. He will never be able to get to 100% of the rated output on the lit because he's at 7600' elevation. Based on the chart and his altitude he's loosing 17% of the rated input - His adjusted rated max btu/hr input is 923,000 not the 1,112,000 Btu/hr as listed in the lit and tech data manual.

His max input % should be around 83%. He's siting at 80%. So only a 2-3% adjustment

CMadatMe

Umm really interested in what's going on with this boiler and the results of those 120 man hours.

mars_6

Mastery solved I hope, sorry for the delay in feed back. had a Viessmann trainer in town last week, as well as my A team in his training class. I was able to get the trainer on sight and lay hands on the unit. The unit seemed to have sustained shipping damage due to a drop as near as the trainer could see. The A side pressure switch for the controls was faulty as well as a crack in the burner head refectory. We did not catch this on delivery and may never have caught it as you have to have an intimate understanding of this boiler. I am receiving the new burner head tomorrow and hope to see what the outcome is from that point. I have to give kudos out to Rampart Supply of Denver and to MJM Associates the Viessmann rep for there help with this problem. I will know in the Am if this has been rectified. Thank you for your helpful input and i will let you know how this pans out. sincerely Matt Four Season Heating Inc. Denver.

mars_6

Well got the new burner assembly installed today, set the coding on the burner to high altitude and the unit failed on a F9 fault code again. I'm beginning to think I'm BETA testing this unit for Viessmann. Are there any fellow wallies that have a CM2 311 installed at elevation in the front range of Colorado? If so I would love any feed back. Thanks Matt

CMadatMe

I gave you the adjustments above. The boiler should NEVER be able to go to 100%. Setting the burner to high altitude is only one step in the process. You have to de-rate the boiler. Based on your altitude your new high end max modulation rate is 83%. You must de-rate by 17% making your new max btu/hr input at 923,000 Btu/hr not 1.2 million as listed in the tech data and literature. You can only get 100% max modulation rate below 1000' elevation.

Be assured you are not BETA testing. Boiler has been in service for almost 2yrs now. Make the correct adjustments.

mars_6

This part is understood, as well as the fact that our gas from our energy provider is only 930 btuh per cubic foot. So Chris if im getting you corectly I need to set the burner control to 83% for the burner control to operate corectly? Its anoying that the many hours spent on teck support line this was never addressed. Thanks for the info Matt

CMadatMe

Yes you need to make your Max Modulation Rate 83%. That's it. See the chart in my first post. If you think your higher then exactly 7600'like 7650 etc you're max is going to be 82-81%%.

You can never ever get 100% of the modulation rate above 1000' elevation. You must start de-rating at that point. So your new btu/hr range is now - 222,000 - 923,000 Btu/hr. Bottom of page 5 of TDM.

http://www.viessmann.ca/content/dam/vi-brands/CA/pdfs/commercial/vitocrossal_200-cm2_sm_gw6b_tdm.pdf

Zman

Chris,
You do derate the expected output based on charts provided by the manufacture.
With most manufactures you do not change the modulation %. You just get less energy at 100%.
Is there something different about viessman?
Carl

CMadatMe

Yes you de-rate the max end of the modulation rate. That's why he's getting the F9 error. Its the logic within the control. Have to remember, control/software is mfg/designed by Viessmann not a 3rd party. If he was pulling the flame off at ignition he'd be getting F8. More then likely he can't reach the set fan speed or the duration is too long trying to get past 82% modulation. That's why when he said in his original post at 80% it was running happy. Once he told the boiler it is in high altitude, the control logic should have automatically de-rated itself to 85%. See "A" on the chart in my first post. Now he has to de-rate manually further based on the added 2,600' of elevation. The high altitude adjustment just takes you to 5,000'. Now when you look at the control from the home screen you think you're getting 100% based on the bars because 85% is the new 100% for the particular application if that makes sense to you.

mars_6

Chris your spot on, have confirmed this with Viessmann Teck support and the boiler to my knowledge has not faulted out yet. Can't thank you enough for the info. Would have been nice for Teck support to have provided it but after many hours on the phone with them I understand there position. Thanks again Matt FSH Denver

nicholas bonham-carter

Once again, the Wall provides better tech support than the manufacturer! Good job!--NBC

CMadatMe

mars said:

Chris your spot on, have confirmed this with Viessmann Teck support and the boiler to my knowledge has not faulted out yet. Can't thank you enough for the info. Would have been nice for Teck support to have provided it but after many hours on the phone with them I understand there position. Thanks again Matt FSH Denver

You're welcome and glad to hear you're all set. Kinda bothers me that the rep who is selling the boiler where it's all about elevation isn't on this. I would think it would be the 1st thing they would have checked. Always start with proper control setup for the application then work from there when troubleshooting.