Venting Burner Through the Roof?

[Klean Spray 14]

I'm setting-up a new hot water machine inside a box truck which sets toward the front of the truck and aprox. 6-ft from any door opening.Currently I'm trying to figure out what type of material to use and most economical way to vent through the roof straight up. I have looked thru past post and have a few ideas but came across a Google search for venting which had someone suggesting the use of Type "B" Gas Venting Ducts for diseal burner. Would this material be o.k. to use with a diseal burner for venting?

Thanks

Type "B" Gas Vent & "Big Vent"

Metal-Fab's round and oval Type-B vent is listed by Underwriters Laboratoriesfor use with approved category 1 gas furnaces, heaters, and boilers. A category1 appliance operates with a non-positive vent static pressure. The double walldesign of B-vent enables the product to be used in homes and commercialbuildings at close clearance to combustible. Metal-Fab's B-vent designincorporates features that make installation quick, easy, and safe.

Efficiently vents Category I natural gas and propane-fueled appliances

Resilient dual-layer construction

6" openings

.012" aluminum inner liner and .018" galvanized steel outer wall

Secure twist-lock connections

Requires only 1" clearance to combustibles

25-year warranty

UL and ULC Listed

Available in five lengths

[AquaMike 36]

WE use an insulated stainless pipe with a flip style lid and haven't had a problem in over 23 years. Once in awhile someone will forget to open the vent and it gets a little smokey in the truck but other than our own stupidity it works well.

[Douglas Hicks 128]

Do a search for "vent, roof" There are lot's of posts on your question. I vented through the roof of my step van and now the trailer. I used Metalbestos for the roof pentration. What ever the size of the burner outlet, do not go smaller. I am not sure B Vent is large enough.

[centexpw 16]

Exhaust for the burner should be as short as possible and as direct as possible. The size should be same size or larger. Bigger is better for the simple reason this is a blower force fed burner and any obstruction in the exhaust will cause back pressure and the burner wont run correctly. You may experience burner firing problems, excessive heat build up, poor combustion, soot buildup. We had a burner which had the same size exhaust but it was about 5' long and it worked fine but the extra length caused a little bit of back pressure on the burner. The burner worked fine but the back pressure caused the exhaust to slow down and the burner chamber got excessively hot, which caused the components to get hot. The Becket ignition module would fail after 300 hrs from the heat. It took 4 replacements to figure it out.

[Douglas Hicks 128]

To expand on Michael's post, if you cannot use a straight exhaust, use 45° bends and not 90° bends. there is a lot more static pressure buildup with a 90°. I favor the adjustable bends instead of fixed bends.

When you are done, put sheet metal screws into the seams and connections.

Use black pipe, galvanized gives off poison fumes when heated.

[Klean Spray 14]

Thanks for input.

[mick m 19]

I saw something on the TV a while back showing the answer to this sort of question. The extension of the exhaust needs to sit above the chimmny, not joined to it. As the heat rises, it causes an updraft which increases the air flow upwards & sucks out the exhaust. The same principle is used to inflate those emergency escape slides on large aircraft.

[CNY Hood Cleaning 27]

got a pic of it or something cause I don't think i've seen it.

I have mine threw the roof using the black pipe with a 45. Then I have it insulated so it doesn't get hot in the trailer heat goes up. The exhaust threw the floor.

[mick m 19]

Sorry, no pics. I know what I mean, but I'm struggling to explain it, so bear with me. The extension, at the bottom of it should be flared out. [imagine a range hood] that sits above the chimmny by about 5 inchs. As the exhaust from the boiler comes out, it creates its own draft, & in turn creates a stronger updraft, which will solve any problems regarding back pressure.

[CNY Hood Cleaning 27]

Oh so same concept that you would have on a water heater in the basement

[Douglas Hicks 128]

I ran my RK 47 from Delco for 13 years. The duct was fastened to the shroud around the coil, not like a gas water heater or furnace. Yesterday, we installed the new RK 47 from Powerwash.net. I did make 2 changes. The plumbing is different, so the connections have been changed. And we left the wheels on, and used ratchet straps to hold the pw into place. Today, we will finish the job and start the pw up and spray some water. Because the burner is slightly different, I do not think we can drain the coil, so we may use an antifreeze tank and run antifreeze through the pump, coil and hoses. Then, when the temp gets above 25, it will be time to go to work.

Any one want to buy a used PW?