On Mar 31, 10:06*pm, wrote:
Well put it this way: The tech said it definitely does not belong 1" above the top cover of the boiler. *But he said if it's been set up like that for 10 years and theres been no problems then leave it alone. * No regulator mfg diagrams show that as one of the placement options. Along the horizontal slope section - no problem - just closer to the boiler or in the middle of that run to the chimney. *He just doesnt think it's something I should spend up to $200 to correct.

-CC

I'm no expert on draft regulators, but thinking about
the location issue, the following occurred to me.
The draft regulator is basicly a door that swings open
against a spring so that as the chimney draft increases
it will open to let more air in and try to keep the draft
to the furnace constant. If that door is in a horizontal
section of flue, the combustion gas stream is only hitting
the edge of the thin metal door and it will have very little
interaction
with the door. The gases pretty much go right by it.
If the regulator is inserted in a vertical
section of flue, when the door opens, the combustion
gas stream is hitting directly against the door and
exerting pressure against it.

That may be the key issue. How big of a difference it
makes, I don't know.