Venting for Pool heater

[tenax]

i'm using a jandy kit as well..5 inch diameter version though as my heater is only 125K. i have the flashing of course on the bottom, about a foot above the heater to prevent backdrafting, then i have about a 12 inch diameter hole in the roof..i have the lift or "roofjack" on the top of the pipe (the flashing shield covers around the pipe and opening through the roof) then the vent cap on top.

best to talk to a natural gas guy on specifications for clearances for piping. your heater manual should give you info for usa or canada, but i'd still suggest checking the coding with a specialist if you really want to make sure your in spec. from my manual, i believe in canada anyway, the minimum specs are:

-the top has to be minimum 1 foot above highest part of the roof.
-12 inches clearance from any flammable material. ( or was it 2 ft..can't recall)
-10 inches from any open vent that would lead to living area (i.e. i have an exhaust vent about 12 ft away for a cooktop ngas stove..i'm sure that would be a good example)

my ngas and electrical guy are coming tomorrow and it will be interesting to see how the ngas guy goes about doing the venting as currently....

- i have a shelf (easy to move if i need to) made of the standard chipboard/mds that is only a few inches away from my pipe.

-when i built my new shed 2 summers ago, i put the pipe straight up from where my old heater was located (basically built around the existing pool equipment location rather than moving anything). the stack was high enough against the top of my pool roof, but my house roof is within 10ft of the stack and if it's supposed to clear that..i'm going to have a darn high stack! (6 ft above my pool shed roof!) and it will be among my trees which i'm not sure is a great idea!

if that is what needs to be done to make the specs happy, i suspect he is going to want to consider angling the exhaust pipe instead so it vents out about 4 ft over where i currently have a whirlybird exhaust vent which would work (switch the 2 would be my plan..i don't want to punch another new hole in my shed roof!)

in terms of clearance to joists, i haven't measured but i don't think there is anyway i am going to get clearance of 12 inches with the joists and if they are considered flammable material given they are built 2 ft on center...which i can't believe would be unusual for a shed anyway.

i believe in canada we are required to install a B class chimney ( i know when i replaced the stack when i built the new shed, i was told by the ngas/sheetmetal company i bought it from that it had to be class B) which in turn may give more tolerances. if you don't know the difference between class A and class B my understanding is class A is a single layer chimney. class B are 2 layer chimneys with a fireproof material in between making them much safer and durable then class A.

i'll report tomorrow once i get my installation done!

[JonnyG]

Thanks for your reply. I actually got a heat/air contractor involved who does work for my father in-law. Not sure exactly what I am getting but it seems to be double-walled piping (class B?). Once I get it, I can let you know how it went. The big problem is that I have a 400K heater so the pipe is enormous (9" diameter).

John

[Poconos]

Heh Heh....try and catch the heat going up that 9" pipe.
Al

[tenax]

no doubt..that is a huge pipe..my install went really well and nice thing was they just used an expander from my piddly 5 inch to the old 6 inch pipe (not so old..put in that chunk about 1.5 years ago and in dog years (or pool years given we only run about 4 months a year) it's about 1 year old and was not cheap good luck in your search but certainly local contractor shouldn't have any problem locating for you..and yes, the double walled is class B..again, can't speak for u.s. specs, but the ngas guy brought an inspector out after install and he didn't blink at how close my shelf was to the double pipe or height relative to my roof height..he was most interested in:

accredited rating certified heater (yep)
proper ngas orifices for the altitude (yep..put em in myself..thank god i read the manual and got them)
bonded equipment..yep..6 guage..bonded bigtime.
all equipment on separate disconnects (switches, but now i know the fancy language)
pool pump and heater (electronic) on a gfci breaker? (yep...)

all is good and working nicely!