Water heater vent cap

[Birdhouse]

Hey all

I'm trying to install one of these propane on demand water heaters, unfortunately I did not have 2k to drop on the cool tiny model that vents through the floor.

I can't seem to find an appropriate steel cap to vent a 4 inch pipe through the roof or the wall.

I found one for a 1.5 pipe and one for a 7 inch pipe.... there must be something!

Whatever it is, I figure it ought to withstand an occasional tree strike and road wind, hopefully not eating rain when driving.

Another idea I had was if I was to use a flexible duct "dryer hose" and a 12v booster fan I could blow it out the floor?


Thanks
Franklin

[JDSquared]

Originally Posted by Birdhouse

Hey all

I'm trying to install one of these propane on demand water heaters, unfortunately I did not have 2k to drop on the cool tiny model that vents through the floor.

I can't seem to find an appropriate steel cap to vent a 4 inch pipe through the roof or the wall.

I found one for a 1.5 pipe and one for a 7 inch pipe.... there must be something!

Whatever it is, I figure it ought to withstand an occasional tree strike and road wind, hopefully not eating rain when driving.

Another idea I had was if I was to use a flexible duct "dryer hose" and a 12v booster fan I could blow it out the floor?


Thanks
Franklin

What did you buy? I bought a cheap one off EBAY, I was just going to open the window to vent it when needed. One of the few benefits of not removing my windows I guess.

I'm not near the instruction booklet right now, but I will look at the pictures in there later and see what it says for materials. If it's anything like the wood stoves, I think the vent would need a double wall so it's not transferring heat through your metal roof. But I can't imagine this puts out that kind of heat. Mine isn't hooked up yet though so that's only a guess.

[Birdhouse]

Yeah
One of the cheap ebay ones.
All I know is it says to mount it on a fireproof wallboard, I looked inside and it appears to be single wall construction with no insulation, so it's gonna get Hot.

The prescribed pipe system for venting it is laughable in the context of a bus. Wants a pipe through the wall with a 3 ft riser on the outside and a water drain... lol.


I would really like to vent it downwards. But the vent blowers I've seen, all the steel ones are 120v. All the 12v ones are plastic.

If I mounted it at floor level just before it dumps would probably work fine. Or it might cook?


All of the original windows are gone.
What I do have seems inadequate for something that is definitely supposed to be vented.

[ol trunt]

Rather than guessing how hot the exhaust is how about just firing the heater up and measuring the exhaust temp with an inexpensive IR thermometer. That will give you a reference point as to what materials are safe and at what distance from the hottest part. Those little heaters put out a surprising amount of hot exhaust. Jack

[Jolly Roger bus 223]

your IOM installation operation and maitenance manual will give you the venting configurations and types of piping material that is aloud.
if not followed and a problem arises then the insurance company can and will deny you and if the heater has a performance issue and you didnt vent in accordance with the IOM then any warranty can be denied.
look into concentric vent kits that take care of the intake and exhaust.
i install alot of high capacity boilers and water heaters that allow anything from standard PVC pipe,sch 80 pvc, standard B vent pipe.
let me know if you want help finding the right material.

[Birdhouse]

Originally Posted by Jolly Roger bus 223

your IOM installation operation and maitenance manual will give you the venting configurations and types of piping material that is aloud.
if not followed and a problem arises then the insurance company can and will deny you and if the heater has a performance issue and you didnt vent in accordance with the IOM then any warranty can be denied.
look into concentric vent kits that take care of the intake and exhaust.
i install alot of high capacity boilers and water heaters that allow anything from standard PVC pipe,sch 80 pvc, standard B vent pipe.
let me know if you want help finding the right material.

HI Jolly Roger
Those concentric vents are cool.
However, they still directly violate the liability tenets you posted concern over.

About 2 minutes on Google turned up more reasons not to use them than to do so. Mostly that they seem to suck in the exhaust (whodathunkit), issues with condensation, they seem to be intended for use with a blower, not just relying on draft,

I don't understand how they do not catch fire/droop/stink etc with the heat that is involved.

Somebody figured a 12v plastic blower at floor level would melt... if these survive, why wouldn't that?


I probably will just go with the manufacturer prescribed wall mounted goofy pipe, and make it removable for travel. As much as that idea does not really appeal to me.

I am very open to any other suggestions or why the concentric really is a great idea?

What sort of vent caps are they using on these food trucks? They are always on the move and certainly aren't all using traditional rv parts.

[Jolly Roger bus 223]

what make and model is your water heater? so i can look at your IOM and maybe help come up with a solution