MN801GAS 060520
– 17 –
Adjustment procedure, summary
Step 1: Set gas pilot operation. See details following.
Step 2: Set high-fire gas flow to match high-fire air. See details following.
Step 3: Adjust the butterfly valve linkage to match low-fire gas to low-fire
air. See details following.
Step 4: Verify operation of burner, appliance, and controls.
Use test instruments
1.
Use combustion test equipment and an accurate manometer or draft
gauge to correctly set the burner as required.
2.
Overfire pressure must not exceed the appliance manufacturer’s recom-
mendations. The burner must never be fired at an overfire pressure more
than 0.60 inches w.c.
When the overfire pressure is positive, the maximum burner
firing rate is reduced. The firing rate is also reduced for
altitudes higher than 2000 feet above sea level.
3.
Adjust the burner fuel and air settings using the following procedures.
When adjustment has been completed, the CO
2
(or O
2
) should be within
the ranges in Table 6, at both low fire and high fir
e.
Table 6
Allowable values of CO
2
and O
2
Fuel
CO
2
O
2
Minimum Maximum Maximum Minimum
Natural Gas
8.5 %
10.0 %
6.2 %
3.6 %
Propane
9.5 %
11.2 %
6.0 %
3.5 %
7. Adjust the burner using test instruments
The settings given in Section 6 are initial settings
only. You must use test instruments to check
combustion,
and adjust the burner as necessary, fol-
lowing the procedures given in the following pages of
this manual. Failure
to properly adjust the burner can
result in severe personal injury, death or substantial
property damage.
Step 1
Check gas pilot operation
The Model 801GAS uses a gas pilot for ignition of the gas
main flame. The gas pilot is ignited by the pilot electrode.
1.
Make sure the gas line has been completely bled. Then turn the service
switch to ON.
2.
The pilot will usually light the first time once the pilot gas train has been
completely purged of air.
3.
The pilot flame is approximately 75 MBH, and is large enough to be
heard when lit. If the pilot fails to light, be sure the gas line has been bled
properly. If it still fails to light, increase the pilot gas pressure to 4 inches
w.c. If the primary control is equipped with a pilot test hold switch, it can
be used to hold the pilot “on” while adjusting pilot gas pressure.
4.
Follow the instructions in the primary control instruction manual to check
flame signal. Make sure the flame signal is steady, and greater than the
required minimum for the UV sensor.
5.
Check and ensure that the bent ignitor (Figure 12) is approximately
centered in pilot assembly. If not, loosen electrode locking nut, rotate
assembly and tighten nut.
The linkage between the damper motor arm and the
air damper crank is set at the factory, and should ONLY
need adjustment if the damper motor or the damper
rod is replaced. With the burner in high-fire position,
there should be minimal play in the connecting rod.
DO NOT change this linkage setting.
Smell around the gas train and check all joints with
a soap suds mixture to ensure the gas train and all
components are tight and leak-free. Shut down the
burner and correct any leak immediately. Failure to
comply could result in severe personal injury, death
or substantial property damage.
Figure 12
Pilot Spark Gap
Figure 12A
Pilot Test Port
3/32"-1/8"
