Vitodens Venting - Want to Use Longer Vent Pipe

joel_19

Are you a home owner?? Your Viessmann pro installer will have the answers for you. I would just move the boiler to the outside wall in the basement.

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Tom Hopkins

What are the consequences of extending the venting?

The boiler I have selected for my home is the Vitodens 200 15-60. The max equivalent length of the vent (extending horizontally) is 20 ft. The problem I have is that my mechanical room is smack in the middle of my basement so that there are no exterior walls within 20 ft. I need about 31 feet to get the vent to a suitable vent location.

Have any of you exceeded the max vent length specified by Viessman by this amount? I am told that extending the vent will cut the boiler's top end heat output. In my case that is probably okay because my house is sized at 185,000 BTU/hr and the 15-60 puts out 230,000 BTU/hr. I could afford to lose 20% off the top end without any worries. I was also told that Viessman's old manuals used to list the amount it would derate the boiler if the max vent length was exceeded (the number I heard was that for the 15-60 an additional 5 feet of vent would derate the boiler by 5%). I am interested in your thoughts on this.

ALH_4

Vent length

I wouldn't do it with the concentric vent. I have gone over by 3 feet on an 8-32, but never 11 feet on a 15-60. You can go to 40 feet by pulling combustion air from the room and using 4" CPVC to vent, though it sounds like you would have trouble getting combustion air to that room as well?

Mike T., Swampeast MO

Viessmann is incredibly particular about venting their ultimate creation. The boiler itself is small, nearly silent and easy to place in nearly any location.

Frankly I'd "remote" mount the boiler, increase the primary side piping by one size (including any indirect) and insulate such very well before I considered "alternate" venting...

dblagent007_2

Yeah that is one solution I have considered. I actually have a second mechanical room up on the second floor that I could put the boiler in. The problem is that the water heater won't fit in that mechanical room so it would end up in the basement mechanical room. It would probably take about 30 feet of piping to connect the boiler in the upstairs mechanical room to the water heater in the downstairs mechanical room. My understanding is that having the sensor for the water heater so far away may cause problems.

hydronx_3

hybid venting

Viessmann has added 2 pipe venting options to the Vitodens. It Doesn't add much for your maximum length versus the concentric, but they do have a hybrid setup where you can pull combustion air horizontally and vent vertically that might work for your application. You would have to check lengths. It still gives sealed combustion. If you still don't meet the length max, the option that gives you the most flue vent is like Andrew said to pull combustion air from the room and use CPVC or stainless for the vent. Though I am told the approved CPVC is still not available in the USA.

hydronx_3

Remote DHW

I am interested in knowing if having the DHW aways from the boiler is going to be an issue as I have a current job in works where that is the case (probably 30-40 feet) Do you have experience with this being a problem?

Glen

joel_19

Remote HW

You could put the tank 500 feet away if you want who cares it's just another zone just pipe and pump correctly

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Andrew Hagen_2

Remote boiler

I once remote-mounted a three temp Vitodens 15-60 where the boiler was at the back of the house in a special room built for the boilers, the pump panel was in a closet inside the house, and the water heaters (3 in parallel) were in the crawlspace. To add to it, the Comfortrol interface was remote mounted in the closet with the pump panel. It works fine, but troubleshooting the system is a pain unless you have two people with 2-way radios.

Justme_8

CPVC

Viessmann US stocks CPVC

dblagent007_2

Final Verdict

Okay, after a TREMENDOUS amount of research (mostly on my own) this is what I have found out. Viessmann will let you do alternate venting configurations, but you have to draw up your proposed venting solution and send it in to their engineer in Canada who runs the numbers and gives you a yea or a nay on the design. So if you can't meet the requirements in their manuals, you still have other options.

I called the engineer and spoke with him personally for 10-15 minutes. The solution I finally arrived at was to upsize my pipes to 6" instead of the standard 4". This allowed me to go the extra distance that I needed to properly vent the boiler. My plan right now is to use regular 6" PVC or ABS pipe for the air intake and then use 6" CPVC pipe for the exhaust. The CPVC I plan on using is shown here: http://www.plastinetics.com/d-fittng.htm The CPVC costs a fortune, especially the larger stuff, which is why I am using other materials for the intake.