Venting the Water Heater

Venting the Water Heater

May 28, 2015 Categories Camper Van

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After days of procrastinating, I finally installed the exhaust vent for the water heater. Since this was something that was completely new to me, I wanted to make sure I did it right because doing it wrong could allow carbon monoxide to build up in the van. Granted, with as little use that the water heater is going to see, I doubt it would be much of an issue, but I’d still prefer to do it correctly.

I did a lot of research and tried checking out blogs of other people’s installs. The research, of course, only applied to home installations and the blogs were mostly a disaster for information and were essentially examples of what not to do based on what little I already knew from the research.

There are a few different types of venting out there and being completely new to this, I’ll be honest, it was frustrating. Venting comes in single wall, double wall, aluminum, galvanized steel, PVC, flexible venting, dryer venting, and maybe even more, I’m not sure. Lots of options, huh? Well, not if you want to do it correctly. Let’s go through each type of ventilation material.

  • Dryer Vent. Likely to be a flexible vinyl or mylar foil tubing which is then connected to a rigid metal ducting. The vinyl and mylar materials are NOT designed to be used with a gas burning appliance such as a water heater.
  • Flexible Vent. Looks kind like the mylar foil dryer vent, but they make actual kits designed for water heaters. However, it is NOT designed to go through walls or roofs. Most of the sites I looked at recommended not even using it.
  • PVC. This is not the same as plumbing PVC. I didn’t look into this much because Home Depot didn’t have any that I could see in the venting/ducting isle. I know you can use it for water heaters because the tankless water heater in the basement has a PVC vent going outside and it was installed professionally. Whether or not you can use it on all water heaters or only certain models, I don’t know.
  • Aluminum/Galvanized Steel. This is what you are supposed to use!

Single wall or double wall? Single wall venting requires up to a 6″ clearance to any combustible material and isn’t supposed to pass through any ceiling or wall. Double wall venting only needs 1″ clearance to combustible material and can pass through a wall or ceiling.

Type B/Type L. Yes, it gets even more specific. When selecting venting, make sure you get some specifically marked as either a Type B or Type L vent, which are designed for venting high temperature gases.  Type B can support gases up to 480° F (which includes water heaters) and Type L can support up to 570° F.

Flashing. Flashing is a metal “cone” attached to a flat base that sits directly on top of the roof and the vent comes out through the top of it. On a house, shingles get layered on top of it to keep water out. Since I did this on a van, I sealed it up with both putty and silicone.

Storm Collar. A storm collar is a flared ring that goes around the pipe directly over the flashing to prevent water from getting in. The storm collar should be sealed in place using 100% silicone sealant.

Vent Cap. This goes on top of the pipe to keep rain out as well as birds and other junk. Technically, this is supposed to be at least 12″ above the roof line, but since I did this on a van and the water heater will get minimal usage, I installed it as low as possible in an attempt to keep it from sticking out (as an eye sore) any more than it has to.

So, let’s sum it up. To vent a water heater, you should be buying double wall, Type B, galvanized steel venting which will have an aluminum inner wall. You’ll also need to buy a flashing, storm collar, and vent cap.

Also, don’t reduce the vent size! If it comes with a 4″ vent on top, run 4″ venting. However, if it comes with a 3″ vent, feel free to increase it to a 4″ if you want. Just don’t decrease the size.

Anywho, let’s get on with it. I started my install by drilling some pilot holes for the jigsaw and then cut a roughly 6″ wide hole in my roof, directly above the water heater.

Because I prefer to be safe, I took a 6″ wide section of vent and cut it to fit through the hole I just made in the roof. I did this to ensure the insulation and everything stays away from the vent. Since it’s 6″ wide, my 4″ vent will fit directly in the center, giving me 1″ of space on each side.

Then I put in my vent. Where it attaches to the water heater, I used sheet metal screws to attach it to the vent hood and then wrapped it in some foil tape. Some sites recommended against using any tape because if the pipe begins to corrode, you won’t be able to see it in that area. I’m not really worried about corrosion, but I am concerned about CO buildup and I feel the tape will help give an air tight seal.

I bought a metal collar to not only clean up the appearance, but it also keeps the pipe nice and centered. I attached it with a thick bead of silicone and then added some sheet metal screws to hold it in place.

Next up came the flashing. I trimmed off about 1 1/2″ from every side on the base of the flashing and then rounded off the corners; this made it smaller and much easier to work with. I used a layer of putty tape around the outside edge and put a couple beads of silicone on the inner area before putting it in place on the roof. Again, the vent pipe is “supposed” to extend 12″ above the roof for proper ventilation, but I’m trying to keep it as low profile as possible, so I barely have the pipe rising above the flashing level.

I screwed the flashing down really well and installed the storm collar and vent cap. The storm collar has silicone all the way around it to keep out water and the vent cap is held in place with three sheet metal screws. I covered the screw heads in the flashing with some roof sealant. I don’t think it looks too bad, but I definitely think the van just lost any and all hope of ever being stealthy. People are either gonna know I’m living in it or just think I’m running a portable meth lab.

After a quick lunch break, I decided to make some custom fit window sun shades with the extra Reflectix I still had from doing all the insulation. The cab area is a hot box when working inside the van and I’m hoping that the sun shades will help keep some of the heat out. With the exception of a couple spots where I trimmed just a sliver too much off, they block out all light.

The only other thing I did today was install a small piece of window trim that I’m using as an LED light track. It’s an “L” shaped trim piece and the LED lights fit in it perfectly. For now, I just set the lights in place, but after everything gets stained, they will be adhered with the 3M tape which comes attached to the bottom of the lights. Even in the daylight, you can see they’re pretty bright. I’m gonna test them out tonight to see how well they really illuminate things. I also only did one side of the van as a test to see if the window trim would work as a light track. Since it did, I’m gonna buy another length of it and do the opposite wall, too. I have a dimmer for the lights, so I’ll be able to adjust the lights to whatever level I want.

UPDATE: 9:30pm. I took a pic of the LED light strip at night and wow, I’m impressed with how bright it is. I’d never even know it’s night out. I’m definitely gonna be using that dimmer switch once the other side is installed.

I wanted to finish paneling the water heater cabinet today, but when I went to start on it, I totally forgot I used up all my plywood when I built the doors for all the cabinets. Since I had already gone to Home Depot this morning, I didn’t feel like going back again. Oh, well. I guess it’ll have to wait until tomorrow.

I’ve been testing out a few different stains this week during the evenings. I was gonna stain it all grey to make the wood look aged, but after testing it, the stain just looks terrible. Kind of like a thin layer of cheap, diluted paint. One of the ones I really like is called Special Walnut. It’s a nice brown with just a hint of grey and doesn’t have a glossy look. I’m gonna test some more on mixing a couple stains together and see how they look, but more than likely, the Special Walnut is what I’ll end up using.

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