Venting Unit Heater

[Innov8tive1]

If you read my caution thread about old furnaces in garages you will know that I am installing a natural gas unit heater in my shop. After waiting 3 weeks for my "vent kit" to arrive I got a call today that it was in. So I went to pick it up and it's just the "special" stainless pipe, that's it, no thimble or any other thru the wall penetration item. So I asked where it was and the guy says "well as long as you have an inch all around between the pipe and combustible material you're all good"............so I take that to mean I should cut a hole 6" in diameter because the pipe is 4"? Then I'll have a 1" gap for what? Fresh air!?!?!?!?
So he sends one of his guys out to the back to look for a thimble. He found one which was for 3" pipe and a couple that are suitable for roof penetration but not what we need.
So my question is, when he ordered the venting for the unit heater I had purchased from them, should he not have thought about ordering a thimble too? I told him to get me EVERYTHING I would need to PROPERLY install it. I told him it was going out the wall horizontally, I told him I had vinyl siding on the outside wall.
WTF? So now I'm waiting once again for more parts to arrive......Not happy!

 

[z28dad]

What brand name / model of heater are you installing. I purchased a Mr heater horizontal kit and then found out that I would have to go through the roof due to clearance issues. I was able to still use most parts, but I also went to Lowe's for any extras. If I had it to do over again, I would have just purchased everything from Lowe's.

As far as vinyl siding goes I was planning on using one of these to mount the thimble to:

http://www.amazon.com/dp/B000DZBGEG/?tag=atomicindus08-20

It has a built in J and would give a nice finish look to the exterior of the building.

 

[hess]

If like on a wood stove pipe they make a collr that fits around the pipe it would take 2 one for inside one for outside they go up to the wall and hold the pipe

 

[hardhat]

They make a collar like mentioned above that covers up the gap from pipe to thimble. Look up Cinnabar pipe on the internet. The guy there is great to deal with and ships fast.

 

[Innov8tive1]

It is a Reznor UDAP 75KBTU unit heater. I just wish the place I ordered it from would have ordered everything I needed, when I went in I told him I would need everything!

 

[danski0224]

If the parts you have are from a vent pipe manufacturer, you can probably order the parts elsewhere. Odds are that Reznor did not make the parts.

Special order stuff can sometimes really **** because it is never stocked and there may be order minimums.

The fact that you are special ordering these items proves that the supplier is not stocking the parts for a proper installation.

I am looking at a commercial style filter grille that holds a 2" filter, and I was quoted a 4 work week lead time. Obviously, they do not want to sell these, so why list it in the damn catalog?

Oh, and clearances between single wall pipe and combustibles are 6", not 1". Some vent manufacturers make their stuff 8" so the inspector doesn't have to get out the tape measure.

 

[Innov8tive1]

Thanks danski, just for clarification, if I had double wall pipe what clearance would I need?
To use the single wall I would need 6" all around the pipe where in penetrates the OSB sheeting and vinyl siding?
I'm sure the vent pipe and other parts were not made by Reznor but the dealer I bought it from ordered everything from the same supplier. I realize the requirements have changes as to what vent pipe can be used but I would have thought they could have put 2 and 2 together and ordered me everything I needed to do the install. Bottom line is either my local dealer didn't order the right stuff or the supplier didn't provide the right info or parts to the dealer. If I knew exactly what I needed I likely could have ordered everything I needed myself and probably had it all here by now. Being as how these unit heaters are pretty common (at least in my area) I would not expect any of the parts to be special order.
I will get more info off the vent pipe that I got and post it. That way I can see if I should even be using the stuff. I am assuming double wall vent would have somewhat tighter clearances.

 

[Innov8tive1]

Even better, here is a picture of the label. Looks like it requires 8" to combustibles. Will the use of a thimble reduce this requirement?
I'll now have to look up how hot the exhaust gets to see if I can even use it........

 

[danski0224]

You cannot use double wall vent pipe to horizontally vent your heater.

You must use a CAT II stainless steel single wall pipe, unless your heater has provisions for a concentric intake and exhaust system.

Here are a couple of specifications: CAT III vent should be listed to UL 1738. Also, the unit should have a safety listing by a recognized test lab to ANSI Z83.8 for unit heaters.

American Metal Products Group makes a single wall stainless product called Amerivent Model SW Special Gas Vent.

That is what you need... or anything similar, as long as the vent system is UL listed and installed properly. You could probably go to that www address listed on your product and order the parts. Note the different clearances for enclosed/open and horizontal/vertical. As long as you follow the directions, it will work.

Vent temperature of a typical induced draft appliance will not exceed those label ratings.

The problems you are having are typical of DIY or contractor installations when the manual isn't read. The parts counter guys are not always up to the task (but there are some good ones out there).

 

[bkarnuth]

I know this was posted a long time ago, but i noticed you said you couldn't use class B venting on Reznor if you vented it horizontally... what about vertically? I have a UDAP60 and the manual says horizontally AND vertically you must use Class III venting. I'd rather use class B because it is about 3-4 times cheaper than the class III. thanks for your time!

Bryan

 

[danski0224]

I know this was posted a long time ago, but i noticed you said you couldn't use class B venting on Reznor if you vented it horizontally... what about vertically? I have a UDAP60 and the manual says horizontally AND vertically you must use Class III venting. I'd rather use class B because it is about 3-4 times cheaper than the class III. thanks for your time!

Bryan

Type B vent is approved for vertical installations- says so right in the manual.

Lots of people think they can DIY venting of furnaces, boilers and other combustion appliances, but it is obvious from the questions that most do not know what they are doing... and unfortunately, some so-called "professionals" should be included.

If the equipment manufacturer specifies something in particular, venting in this case, then you must follow the manufacturer guidelines. Then there could be code issues with using single wall flue pipe exposed in an attic for example.

If you do not know what you are doing, there are 2 options:

(1) Hire someone that does know what they are doing

(2) Read the manual(s) and familiarize yourself with the applicable building codes

All of the factory built chimney manufacturers have very detailed installation instructions and specifications available online. Take the time to read them.

Your municipality may not have local code enforcement "per se", but there is still the NFPA 54 (National Fuel Gas Code- this covers appliance venting) and IRC (International Residential Building Code).

The inner liner of Type B vent is aluminum. I would suspect that fuel gas condensation, if/when it occurs, can/will corrode the inner liner. Therefore, the manufacturer is specifying a stainless steel product.

 

[sammer]

When I was installing my UDAS-45, I couldn't find anyone that knew what cat-III venting was, so built it out of galvanised 24g pipe.
The inspector didn't like that and told me it had to be cat-III as per the venting instructions. I went to every supply house within 100km and found nobody knew what I was talking about. Then I called all the heating and plumbing contractors in town.
They all said the same thing, "I just use B-vent"
These rules changed a few years ago but because the licenced guys never have to get their stuff inspected they just didn't know.
I finally found a place in Calgary that sells Novavent, and had it delivered.
My buddy had the same argument with the guy installing his reznor. This one told him if it is under 100k btu you can just use galvanized, and that there are no clearance restrictions. He pointed to the venting instructions that came with his unit and said "you're going to follow this!".
He got home from work to find the venting was catIII but was only 5" from an opening window. The contactor says "it's all good I've signed it off. I'm not moving it." That was 2 weeks ago and he's lived up to his word!

The inspection process for gas and electrical in this area is a little whacked.
Contractors don't get inspected most time, the inspectors are way too busy trying to keep up with all the homeowner permit inspections.

sam

 

[danski0224]

He got home from work to find the venting was catIII but was only 5" from an opening window. The contactor says "it's all good I've signed it off. I'm not moving it." That was 2 weeks ago and he's lived up to his word!

The inspection process for gas and electrical in this area is a little whacked.
Contractors don't get inspected most time, the inspectors are way too busy trying to keep up with all the homeowner permit inspections.

If the contractor is licensed or registered in the municipality, the improper venting could be pushed up the chain. Yes, I know that not all contractors need licensing. If it really is 5" from an operable window, it is installed wrong.

Contractor work that isn't inspected is just plain wrong- it opens the doors to easy corner cutting opportunities. Your paid public servants are negligent in their duties. An issue should be made about that, for sure.

 

[truckman5000]

If you read my caution thread about old furnaces in garages you will know that I am installing a natural gas unit heater in my shop. After waiting 3 weeks for my "vent kit" to arrive I got a call today that it was in. So I went to pick it up and it's just the "special" stainless pipe, that's it, no thimble or any other thru the wall penetration item. So I asked where it was and the guy says "well as long as you have an inch all around between the pipe and combustible material you're all good"............so I take that to mean I should cut a hole 6" in diameter because the pipe is 4"? Then I'll have a 1" gap for what? Fresh air!?!?!?!?
So he sends one of his guys out to the back to look for a thimble. He found one which was for 3" pipe and a couple that are suitable for roof penetration but not what we need.
So my question is, when he ordered the venting for the unit heater I had purchased from them, should he not have thought about ordering a thimble too? I told him to get me EVERYTHING I would need to PROPERLY install it. I told him it was going out the wall horizontally, I told him I had vinyl siding on the outside wall.
WTF? So now I'm waiting once again for more parts to arrive......Not happy!

Guys that work the counter in an hvac supply house make 12 an hour...They have no clue.

You can order what you need online, and have it delivered to your door.
Google 4 inck wall thimble