48
Rev. 05/2020
49
Rev. 05/2020
CHAPTER 14
AIR SUPPLY
Combustion Air Blower(s) and Flipper Assembly(s)
Principles
The combustion air blowers and flipper assemblies supply air for combustion inside the
firebox. The flipper assemblies keep air out of the firebox when combustion is not needed.
These components are removable and serviceable.
Operation of the Combustion Air Blower(s) and Flipper Assembly(s)
1)
When the HTF temperature reaches the
high HTF temperature
setting, the aquastat
turns the blower(s)
off
. At this point, the hinged flipper falls shut, preventing air from
getting into the firebox.
2)
When the HTF temperature reaches the
low HTF temperature
setting, the aquastat
turns the blower(s)
on
. At this point,
the hinged flipper opens from the force of the
blower(s) and allows air into the firebox.
3) The hinged flipper
must
completely open
and close all of the time. When it is closed,
it must seal completely. If more than a
“wiff” of smoke is coming from the chimney
when the blower(s) has been off for
approximately 10 minutes, this is a strong
indication the hinged flipper is not shutting
properly.
Maintenance / Result
1) Clean the fin blades of the squirrel cage fan.
2) Ensure the flipper assembly is clean and seals completely when closed.
Steps to Maintain your Blower / Flipper Assembly.
1) Turn off the main power supply to the furnace.
2) Loosen and remove the two thumb nuts securing the blower / flipper assembly to the
large air tube, and remove the blower / flipper assembly.
3) With a small brush, scrape any dust or residue that has accumulated on the fins of the
blower.
4) With a small brush or scraper, scrape any dust or residue built up on the flipper
assembly.
5) Ensure the flipper is resting completely on its seat. If it is not resting completely,
perhaps there is dust or soot built up on the flipper, or some other obstruction not
allowing it to close tightly.
6) Securely fasten the blower/flipper assembly back to the large air tube ensuring there
are no air leaks.
THE FLIPPER MUST OPERATE PERFECTLY OR PROBLEMS QUICKLY ARISE.
Flipper Assembly
Removal and Replacement
1) Turn off the main power supply to the furnace.
2) Loosen and remove the thumbnuts securing the blower/flipper assembly to the air
tube.
3) Disconnect the electrical wire from the blower.
4) Remove the flipper assembly from the blower by removing the four bolts. This will
require a 7/16 inch wrench.
5) Attach the existing flipper assembly to the new blower.
6) Rewire the electrical wire to the blower.
Contact a licensed electrician if you have
any questions.
7) Securely fasten the blower back to the air tube ensuring that there are no air leaks.
If the flipper is unable to open and close freely, or remains partially open or partially closed,
the furnace will starve for air resulting in a smoldering fire instead of an intense fire.
More smoke and creosote is the result. If the flipper is not operating correctly, it causes a
snowball effect of problems.
MAINTAIN THE FLIPPER!
Air Box(s)
Principle
The air box is designed to distribute the appropriate percentage of air from the blower(s),
into different areas of the firebox so the fire will burn efficiently and clean.
Maintenance / Result
Check for ashes in the air box. If ashes are in the air box, they may interfere with the
opening and closing of the flipper. If ashes cover
the air outlets, less air will get into the firebox. When
raking ashes, be careful not to pull the ashes over or
into the air box(s).
Be certain the ashes are cold
and extinguished before attempting to remove
ashes from the air box.
To maintain the air box, remove the blower / flipper
assembly and clean the ashes out of the air box with
a mini-vacuum that is made for ashes, metal brush
or metal scraper. You may need to loosen up hard
packed ashes. Securely fasten the blower / flipper
assembly back onto the large air tube ensuring there
are no air leaks.
Air Box
THE FLIPPER MUST OPERATE PERFECTLY OR
PROBLEMS QUICKLY ARISE.
