Draft-o-Stat Q

Alan

I have a question about a draft damper (if that is the correct jargon) that is part of
an American Standard oil boiler at a house I am restoring.
Probably a 1950s vintage, it has a swiveling metal plate with an adjustable weight knob.
I am wondering if the damper plate is suppose to swing down to the closed position when the boiler
is not firing.
I noticed today the damper plate was swiveling mostly in the opened position and cold air leaking in.
There is some sort of a Honeywell box with a probe that is inserted in the exhaust tube, positioned between the boiler and the draft damper.
I think the nameplate says Vent-O-Stat.

I would appreciate any info on what I should be looking for.
The boiler in our house is a Burnham gas with a draft hood, so I have no frame of reference with this other
damper plate setup.

Thanks for your help,

Alan

Tom M.

Draft Regulator

What you're looking at is the draft regulator. Most oil fired systems use them to keep a constant draft from the chimney. When the chimney heats up and pulls too hard, the damper will open to let basement air into the fluepipe.This will reduce the draft by (a) decreasing the volume pulled from the boiler and (b) cooling the chimney so it doesn't pull so hard. You will also see it reacting to wind conditions as the pressure changes at the chimney top. It should be adjusted by an oil burner technician with proper testing equipment. The Honeywell unit is the stack relay which is the primary oil burner safety control on your system. It uses the heat in the exhaust to verify that a flame has been established. This should be tested by the technician on an annual cleaning to be sure that it will lock the burner out if there is not a flame.

Alan

Draft-o-stat

Thank-you, Tom, for the explanation.

To make sure folks understand I am not bypassing knowledgeable technicians....
The system was tuned and cleaned by a 70+ year old gentleman (with the oil company) who has been servicing it
since the house was built (!).
He pointed out the Beckett burner is fairly new - installed about three years ago.
As for the draft regulator, he did check it but I didn't think to ask any question about the function of it.

I observe the chimney stack from next door and I can tell when the boiler is running because the background view becomes distorted by the rising heat. There is absolutely no visible soot or smoke, which is what he told me to look out for.
(Certain times of the day when the sun is at a particular angle even minute soot/smoke would be very obvious.)

RE - "You will also see it reacting to wind conditions as the pressure changes at the chimney top."
So....it's not unusual for the damper plate to swivel a bit and open when the boiler is not burning ?
I can tell it is easily affected by the pressure changes in the chimney since it is a finely balanced swiveling mechanism.

thanks again for your reply,

Alan