Thread: oil boiler venting dangerous

I know that this is wrong, but just wondered what comments it may generate. Oil boiler is vented through the wall, mechanical draft.

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I am not sure there is anything wrong. Its mechanical draft? Is it contrary to manufactures instructions?

It is mechanical. I have the model and serial number. I have never seen a oil boiler with this kind of venting setup.

It looks improvised to me. It looks like a gas vent that has been altered to work with an oil burner.

However I was wrong, see the manual here:

http://www.ecrinternational.com/secu...cument/266.pdf

Originally Posted by John Kogel

It looks improvised to me. It looks like a gas vent that has been altered to work with an oil burner. I would call it wrong until proven otherwise. Higher flue temp, no?

I think John nailed it on all of the above ... plus the joints are backward.

Hopefully, Bob H. will reply to this and provide more specific information.

Now that I look at the pictures on my computer and not my iphone I can see in the third picture scorching and sooting on the elbow.

Also black staining under burner.

I'm not saying that installation is correct, but mechanical venting systems for oil burners do exist. Manufacturers like Field Controls make them. There are a lot of ways to screw up the installation. The motors in the vent fan also don't seem to have a long life expectancy.

I did not quite know what to say in the report, as I found pictures on line that showed the exact venting for oil boilers. But as was noted, there is evidence of leaking flue gasses, and it just looks like a hack job.

Not sure of what I'm seeing here. Where is the mechanical exhauster? This appears to be a typical natural draft oil fired boiler with a makeup air system piped directly to the burner, an unsecured increaser off the appliance collar to unapproved stainless steel chimney liner used as a chimney connector and unsupported to a decreaser that has visible soot stains at the hand crimped male-down joint indicating flue gas spillage to a concentric vent termination/ intake. Unlisted single walled connector for oil carries an 18" clearance to combustibles unless stated otherwise by the appliance mfr. The single walled unlisted ell's gores are partially sealed with high temp. RTV silicone indicating a positive flue gas application. If the venting is under positive pressure, it must be listed for that application. Note that while the codes do not dictate flow direction on male/ female pipe ends but anytime you have the potential for condensate drainage in a natural draft vent, the male should point back towards the appliance. If the vent system is working properly, any leaks would create a venturi and entrain ambient air into the vent system rather than spill flue gases. SS band clamps are insufficient at securing joints--you need at least three equidistantly spaced screws per joint, preferably ss and oriented so no pipe penetrations between 5-7 O'clock positions on any pipe "horizontal" meaning more than 45° from vertical. On pipe >6" I'd recommend at least another screw min. per joint. Screws in this zone will tend to corrode out first and allow condensate to drip out. The termination was hacked in and will leak. The penetration should be cut out for a framed out box that is flashed to the siding and caulked. The termination would then mount to the bump-out. What are the make and model of the boiler, burner, and mechanical exhaust? More pics?

It is a Utica, SW4W. Serial # UFB25060 REV 2.

- - - Updated - - -

It is a Utica, SW4W. Serial # UFB25060 REV 2.

Thanks Russell. I take back my earlier comment in light of this new information.
I googled that model # and found this 'venting addendum' that shows that very arrangement. Also instructions for applying the goop. Also Fig.5 shows the clamp.

http://www.ecrinternational.com/secu...cument/266.pdf


They used the kit supplied by the manufacturer. But one thing they got wrong. The manual says to run the crimped ends of the pipes in the direction of air flow, they say 'running with the air flow'. That I think explains the leaks at the vent pipe junction.

This is a direct vent appliance--not a mechanically vented one. Therefore, the vent is under negative vent pressure. Any gaps in the vent pipe should act as a venturi instead of spilling flue gases. Therefore, either the venting is not balanced or there is sufficient negative pressure within the Combustion Appliance Zone to cause spillage as noted at the joints. The venting addendum to the boiler's instructions do not carry a listing mark. The boiler itself carries listing marks that only address the hydronic aspects of the boiler itself and not the venting. Therefore, acceptance of this venting arrangement would only be acceptable if the AHJ approved it. Otherwise, it is still unacceptable.

The instructions do not provide clear information as to clearances to combustibles from the wall penetration, which could present a fire hazard. A proper listing would provide such information.

Just because a mfr. sells stuff doesn't make it legal or suitable for use.

Originally Posted by Bob Harper

This is a direct vent appliance--not a mechanically vented one. Therefore, the vent is under negative vent pressure. Any gaps in the vent pipe should act as a venturi instead of spilling flue gases.

They might have been aware of a design problem, because the instructions in bold print say to install the pipes with the air flow, (we assume otherwise they will leak, we assume again due to lack of negative pressure.)

Originally Posted by Bob Harper

The venting addendum to the boiler's instructions do not carry a listing mark. The boiler itself carries listing marks that only address the hydronic aspects of the boiler itself and not the venting. Therefore, acceptance of this venting arrangement would only be acceptable if the AHJ approved it. Otherwise, it is still unacceptable.

The instructions do not provide clear information as to clearances to combustibles from the wall penetration, which could present a fire hazard. A proper listing would provide such information.

Just because a mfr. sells stuff doesn't make it legal or suitable for use.

That is interesting, Bob. I think you are suggesting proper testing was never done. I'll just be happy to never see one of those contraptions and have to make a call on it.

Originally Posted by Bob Harper

This is a direct vent appliance--not a mechanically vented one. Therefore, the vent is under negative vent pressure.

Bob,

I can usually follow you enough to figure out what you are referring to and understand it ... usually ... but I don't follow you with the appliance is a direct vent appliance thus the vent is therefore under negative pressure ... seems to me that the vent would only be under negative pressure if there was a mechanical fan at the outlet end of the vent sucking the combustion byproducts out - so I am missing something.

Just trying to figure out what you are describing and understand it.

Originally Posted by Jerry Peck

Bob,

I can usually follow you enough to figure out what you are referring to and understand it ... usually ... but I don't follow you with the appliance is a direct vent appliance thus the vent is therefore under negative pressure ... seems to me that the vent would only be under negative pressure if there was a mechanical fan at the outlet end of the vent sucking the combustion byproducts out - so I am missing something.

Just trying to figure out what you are describing and understand it.

It works similar to a direct vent gas fireplace-air in and flue gases out by natural draft. Direct vent does not mean mechanically vented in any way although some direct vents can be vented so. In this particular application, the exhaust vents by natural draft---no blower.

Originally Posted by Bob Harper

It works similar to a direct vent gas fireplace-air in and flue gases out by natural draft. Direct vent does not mean mechanically vented in any way although some direct vents can be vented so. In this particular application, the exhaust vents by natural draft---no blower.

Got it - I was thinking "negative pressure" as in pressure reduced below atmospheric pressure by means other than natural gravity flow, which does, yes, create a "negative pressure" at the appliance end of the vent as compared to the pressure at the discharge end of the vent.

Thanks, I guess my thinking cap was not on straight.

just wondered what effect the blower for the burner has on the draft. There is a blower on the inlet side of the burner that forces the flame and flue gasses through the boiler chamber and out the vent. Not to suggest this makes it a mechanical draft, but kind of. There was quite a force of flue gasses exiting at the exterior.