Maytag POF1HD091AVFA, Installation, Operation And Maintenance Manual

A.1 OIL BURNER AIR ADJUSTMENT 

The burner air supply is adjusted to maintain the 

fuel to 

air

ratio

 to obtain ideal combustion conditions. A lack of 

air causes "soft" and "sooty" flames, resulting in soot 
build-up throughout the heat exchanger passages. 
Excess combustion air causes a bright roaring fire and 
high stack temperatures resulting in poor fuel 
efficiency. The POF1HD140AVFA and 
POF1HD091AVFA furnaces operate most efficiently 
with a No. 1 smoke spot on the Bacharach Scale. This 
is not necessarily the optimum setting; however, 
because dust will inevitably build up on the air moving 
components of the oil burner assembly. This will result 
in decreased air supply with the potential result of soot 
building up in the flue gas passageways of the heat 
exchanger. Soot behaves as an insulator and impairs 
good heat transfer. Stack temperature will increase, 
and the overall efficiency will decrease. As a means of 
avoiding this problem, it is advisable to adjust the air 
supply to provide no more than a trace smoke spot on 
the Bacharach Scale.  

For complete details, consult the oil burner instruction 
manual provided in the furnace documents envelope. 

Beckett AF Burner 

Adjust the air shutter by loosening the locking screws 
and moving the air shutter, and if necessary, the bulk 
air band. 

A.2 BURNER ELECTRODES 

Adjustment of the electrode tips with respect to each 
other, the nozzle, and to the rest of the burner is very 
important to ensure smooth start-ups and to permit 
efficient combustion. 

Beckett AF Burner

Electrode gap: 5/32 inch. 

Distance above horizontal centerline: 5/16 inch. Older 
instruction sheets specify 7/16 inch. The current 
specification is 5/16 inch. 

Distance ahead of nozzle: 1/16 inch. 

“Z” dimension, the distance from the front of the end 
cone (head) to the face of the nozzle should be 1-1/8 
inches. If a ceramic head is used, the distance from 
the end cone to the nozzle face is increased to 1-3/8 
inches. 

A.3 START UP 

The furnace should be operated for a minimum of 10 
minutes to reach steady state conditions before fine 
tuning combustion. The warm up time is ideal for 
testing the oil pump pressure. 

Drill a 1/4-inch test port in the venting between the 
furnace flue outlet and draft regulator (barometric 
damper). Insert a stack thermometer and note the flue 
gas temperature. The flue gases should be within a 
range of 350°F to 450°F. If the flue gases are below 
the range, it may be necessary to slow down the 
blower fan. If the flue gases are above the range, the 
blower fan may require speeding up. Stack 
temperature varies directly with the system 
temperature rise. System temperature rise is the 
difference between the furnace outlet temperature and 
furnace inlet temperature as measured in the vicinity of 
the connection between the plenum take-offs and the 
trunk ducts.  Temperature rise value is listed on the 
system rating plate. 

Perform a smoke spot test. The smoke spot should not 
exceed No. 1 on the Bacharach Scale. 

After the air adjustments have been completed, re-
check the draft pressure at the test port on the burner 
mounting plate as shown in Figure 2. The draft should 
be adjusted to -0.02 inches w.c. 

In the United States, the Beckett AF Burner may be 
equipped with Beckett's "

Inlet Air Shut-Off

" to increase 

efficiency. (Beckett Part No. AF/A 5861).

NOTE: USE OF THE INLET AIR SHUT-OFF 
COULD CAUSE POST COMBUSTION NOZZLE 
DRIP. 

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