Concentric Flue for Oil Furnace?

[cbass]

I was at a house today with an oil fired furnace with what appeared to be a single walled steel concentric flue system (that terminated under a window). I have never seen a setup quite like this. The flue pipe is flexible and just draped over to the foundation wall. The whole setup was strange. A 9 year old furnace with a carrier coil/plenum, a payne compressor and a Parrsboro Metal Fabricators (i live in PA-Never saw one of these before [apparently a Canadian company]...). All original to the home. i cant find any information on sidewall flues/concentric systems with oil fired systems. When and how do you know it is ok (from a home inspectors standpoint) to use such a flue pipe? Any/all information would be greatly appreciated. Thank you.

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[cbass]

I also wanted to mention that i have seen this type of setup with high efficiency gas furnaces. I was under the impression that these could only be used with systems of higher efficiency than oil systems. In the field, how would one determine if this, or any other sidewall flue system can be used (assuming the manual is not available).

[Inspectorjoe]

Those units are fairly common around here. I had one today. That one is a real hack job. It looks like handyman or homeowner work. The pros around here generally don't use that flex vent connector material. It should be secured and supported a lot better than it is. It also needs a barometric damper. I don't see on in any picture. I see signs of a lot of condensation at the burner. Depending on the BTU rating of the burner and the length of the vent connector, an insulated vent connector may needed. The unit itself should be rated for use with oil.

The discharge appears to be at least 4 feet below the window which is OK. If it was an oil fired boiler supplying an indirect fired water heater, you'd want to warn the buyer to expect exhaust smells to come in the window when it's open. It appears that it's a little closer than the one foot minimum from the ground.

There's certainly enough wrong with this that I'd recommend a full evaluation by an HVAC pro.

[cbass]

Yea, I mentioned all the condensation and to get a cert from an HVAC specialist. The flue pipe was actually touching the oil fill line at one point with no supports at all. What a mess.

[Bill Kibbel]

A 9 year old furnace with a carrier coil/plenum, a payne compressor and a Parrsboro Metal Fabricators (i live in PA-Never saw one of these before [apparently a Canadian company]...).

That certainly looks like a Kerr furnace. Parrsboro Metal Fabricators is probably the fabricator of some of the furnace components. Kerr is a Canadian company. I don't think that venting kit is to be used with a Beckett burner - only Riello.

That one is a real hack job. It looks like handyman or homeowner work. The pros around here generally don't use that flex vent connector material. It should be secured and supported a lot better than it is. It also needs a barometric damper.

I agree with Joe that it is not professionally installed. I disagree about some other issues. The flex is what's included in several of these "balanced flue system" kits. The exhaust is likely (should be) double-wall insulated. A barometric damper is often specifically prohibited from being used with these kits.

Read the manufacturer and model of the vent kit, then look up the installation instructions.

[Bill Kibbel]

It is a Kerr Furnace.

"Founded in 1976, Kerr manufactures its products at the Parrsboro Metal Fabricators plant in Parrsboro, Nova Scotia".

[cbass]

Thanks Bill

[Rob Amaral]

Bill: No power-venter? Just.. as-is? That box outside is just a weather-proof terminus? Never seen anything like that around here..

[Neal Lewis]

Yea, I mentioned all the condensation and to get a cert from an HVAC specialist.

What kind of certification would a HVAC specialist provide?

[Bill Kibbel]

Bill: No power-venter? Just.. as-is? That box outside is just a weather-proof terminus? Never seen anything like that around here..

If the specific furnace and the correct model oil burner is installed, the burner provides enough positive pressure to vent combustion byproducts, without any additional draft inducing device.

The insulated exhaust must also be installed correctly. The instructions usually include: a 1/4" per foot slope/rise on horizontal sections, support every 36" to prevent sagging and a max. length of 20'.

That's why it's important to locate and review the installation instructions for each system.