mod con with longest allowable 4" pvc venting

pat_3

Wondering if anyone might be able to help me out .I am looking for the mod-con boiler that has the longest allowable vent run possible using 4" pvc .It is for a boiler replacement job where the vent and fresh air piping are existing .It is for all low temperature application ,five story home in manhattan,cannot see the majority of the piping .Most of the larger condensing boilers we have done have been around 100 ft max equivalent length ,but from where the boiler is to where its being vented i cannot figure out how it was possible to stay under the allowable distance that I'm familiar with.Venting out of the building lower than the roof doesn't seem to be an option due to "historic district" designation.Anyone have info on a boiler that can vent longer than 100 equivalent feet with 4" pvc ,it would be appreciated.Thank you in advance for any responses.

nicholas bonham-carter

Long vent

If you have to go up the chimney with the new vent pipe, can you use a larger diameter poly-pipe in the chimney?--NBC

Rich_49

What size

boiler does the building require ?  HTP offers equipment with good maximum vent lengths . ModCon 500  boilers can be vented up to 200' with 4" pipe .  Page 31 shows vent lengths . Don't ignore the rest however , something that may be of importance to your install may well be contained .  



http://www.htproducts.com/literature/lp-445-r4.pdf

Don_197

ModCon Venting

The Lochinvar Knight can be vented at its rating up to 150' EACH PIPE (be careful.......some manufacturers count the intake pipe in their "equivalent lengths" ) and can be vented FURTHER than that if you derate the boiler (it just won't put out as many btus as it's rated for). I have yet to see an installation scenario that this was too short a length for.



Don

pat_3

entire home is fully finished

Entire home is fully finished ,and the original venting didn't go through an old chimney chase.Thank you for your response.

pat_3

venting

Thank you very much for your reply,original boiler was 400,000btuh but was massively oversized but now they are asking about snowmelt so maybe a unit from that company is my answer.

pat_3

venting

Thank you very much for your reply,didn't know there was anyway to go beyond the allowable footage and it would just derate it,always thought the manufacturers footage was set in stone.Cant say i ever remember reading anything about that.Will look into it.

pat_3

longest allowable vent

Appreciate your help but just wanted to point out that the 200 feet limit is the exhaust equivalent added to the fresh air equivalent so the max is still 100 feet for exhaust unless I'm misunderstanding the examples given. Thank you

pat_3

longest allowable vent

I think they may have changed the allowable footage on the Knight if it was 150 feet at some earlier time,just left there site and it looks as though its 100 equivalent feet there as well as every other mod con boiler spec I've seen.You had mentioned derating the boiler for longer footage,do you know where i could find specs or literature on doing that?I can only see a limited portion of the piping but I'm pretty confident with the fittings needed the equivalent footage is more than 100. Thanks ,appreciate your time.

gennady

Venting

Starting October 1st, PVC venting is not allowed in NYC.

gennady

HTP

Only h stamped boiler allowed in nyc. As I recall HTP is not h stamped.

pat_3

pvc venting

Yes that has been what i have been told,was told double wall stainless steel by two inspectors and cpvc by another inspector will only be allowed ,do you know what will be allowed for sure and more importantly will it be enforced based on when the permits were pulled for the job?,had serious issues a few yrs back when about 20 of my jobs failed due to using pro-press fittings on the heating systems with permits pulled prior to 2011 i think it was.Luckily for me and to the credit of Viega fighting with the DOB i didn't need to repipe an awful lot of jobs that were at various stages. Though i already heard that to some extent i thank you for the heads up.

pat_3

nyc boiler

Thank you for the heads up,could have been a costly mistake.

Rich_49

H stamped

HTP Mod Con , Elite and Elite Fire Tube all carry an H stamp .

gennady

H stamp

You are right. HTP Versa-hydro not h stamped. I recall seeing some issues with HTP but it was this particular model.