Wall thickness for direct vent

[eagle_3464]

The installation instructions for a direct vent wall mount furnace states a requirement of 4.5" minimum wall thickness. I am planning on building a shallow extension covered with treadbrite to fit to the exterior of my wheelhouse to meet this requirement. What have the rest of you done to meet this requirement, or have you mounted through a thinner wall with success? It crossed my mind but I don't want to take any chances with inadequate venting. Thanks.

[cold one sd]

I used a vinyl siding kit which gave me the correct thickness.

[Ontherocks]

Many just go with the 2" wall, but have problems with the pilot blowing out. I framed a box with 2x4's on the inside that moved the heater out 3.5". It leaves you with a nice glove drying shelf at the heater. Nothing wrong with doing it on the outside as long as you don't go over width.

[Boar]

ok this is interesting, why would a 2 inch wall allow a piolet light to go out and why is the 4.5 inch wall recomeded. really interested in this.

[Ontherocks]

ok this is interesting, why would a 2 inch wall allow a piolet light to go out and why is the 4.5 inch wall recomeded. really interested in this.

I can only assume the Manufacturers recommendation is for safety on the vent, make sure the exhaust does not come back in the intake. I believe the intake being longer will reduce the amount of draft that would cause the pilot to blow out.

How many people do you know that have to park their truck in front of the vent on windy nights or have to completely block the vent to light the pilot?

Last year I never had a pilot go out, even after pulling 300+ miles at speeds up 80mph.

[Hawg]

I believe there could be a SLIGHT venting problem regarding pilots, however I've done it many times on 2x2 walls. There are many ways to shield your exhaust a little to prevent this though. It's never been a big deal for me, just be sure you have a slight downward tilt to the outside on your exhaust pipe so water does't drain inwards, that's a HUGE deal. Here's an old house I had, this way worked great.

[hunter76]

I personally would never put a direct vent heater in a fish house again. I have had two of them, with problems with the pilot getting wind in there and blowing them out. Don't get me wrong they do give out good heat but I would highly recommend getting a fan to blow the heat to the back of your house. A forced fan by far is the way to go. They keep the floor nice and warm and blow the air to the back with ease. Just my 2 cents.

[Hawg]

And the noise. and the batteries.and the service they always require. I have a nice quiet ceiling fan that keeps the air circulating and a dry floor. I am a generator guy though too. There's good and bad about both.

[hunter76]

We have a generator also but I guess I don't really think our furnace is loud. A direct vent would work for our house as its too big. 8x20. And you are right there is good and bad in both. We also hooked up 2 batteries in ours.

[Hawg]

For me this is a debate that's just kind of friendly banter because both work well if installed and insulated right. It is unbelievable though that on all the ice sites like this one how many posts there are about Suburban Furnace problems, they must have had a couple bad years for quality because they have been the leader in that industry for years. Of coarse then there's the good old ice castle under sizing them too.

[eagle_3464]

hunter, I have no doubt a forced air furnace is much more efficient. They do however require much more power to operate. Low on power, no heat and I choose not to go that route. The majority of my use is going to be a few hours in the evening after work and my LED lighting will last for many hours on a small 9ah battery. Therefore there will be no lugging a heavy deep cycle around except for weekends and/or day trips. I do plan to mount a pair of computer fans in the housing to help move the air. Time will tell how much power consumption the computer fans will have but with or without running them, I will have heat.

Thanks for the replies, your comments have confirmed my thoughts of adding an extension to meet the manufacturers requirement.

[Boar]

Thanks guys. Make a whole lota sence. My budy is building a hiuseni andni have an old empire vented hewter for him and was curious. Tue tilting of the exhaust is a good point also. Thanks

[Hawg]

Not too far Boar but just be sure it's enough to drain, just a few degrees. Too far can cause venting problems also.

[Boar]

Right, ok thanks!

[coffee]

Follow the directions for wall thickness exactly. Doesn't matter if you extend on the outside or inside - just do it. I have mine inside - same heater - 12 years never an issue - never a time when pilot blew out. Direct-vent still the best safety record if installed properly. The other plus is that you don't need battery power. Safety first!

[fishinfan]

I believe this to be 100% accurate. I built an amazing fish house last year and the only trouble with it were the heaters either having the pilot blow out or the vent on the outside building up condensation and freezing over. This year I will build the box inside to push the heater out for a total of the 4".

[coffee]

I cannot stress the importance enough - follow the manufacturers directions and do not "customize" the heater and/or vent in any way. One case scenario about 15 years ago - a group built a 10' x 16' house. The guys installing the direct vent heater "customized" the vent because they did not have the correct wall thickness. Different ones of the group began fishing in the house - they complained about pilot going out and feeling "Dizzy" in the house. A furnace expert was asked to inspect the heater install. His findings: Completely replace the 'customized' vent -and- His words: "the 'fishermen' were very lucky - "dizzy" in the evening would more than likely have been "DEAD" had they spent the night". CARBON MONOXIDE IS THE SILENT KILLER! Having said this, I am a proponent of the direct vent heater (installed properly) - and will continue to use mine for years to come.

[38bill]

I used an Empire direct vent in my house. I just added a 2" bump out on the inside of the fish house to make the wall thicker. Heater works great and the pilot light has never gone out and I was out in some very windy days last winter. For those that don't know these heaters are sealed so they cant put gases into the house. The intake air never enters the house itself, just the sealed combustion chamber. Even if the intake pulls in exhaust gases it doesn't cause a safety issue.

[Ontherocks]

Follow the directions for wall thickness exactly. Doesn't matter if you extend on the outside or inside - just do it. I have mine inside - same heater - 12 years never an issue - never a time when pilot blew out. Direct-vent still the best safety record if installed properly. The other plus is that you don't need battery power. Safety first!

+1, Safety first. Install it correctly and don't mess around with carbon monoxide from improper venting. Even modifying or covering the outside of the vent could be dangerous.

Empire does make a fan kit, but it is 120vac. The nice thing is you do not need power to run the heater.