Operator`s manual

PUREHEAT™ HYDRONIC AIR HEATER OPERATOR’S MANUAL – SECTION 3
3- 4 © 2006 Ground Heaters, Inc. V. 2, Rev. 09/01/06
Use air band and shutter settings and fuel pressure adjustments to obtain an Exhaust O
2
value of 3 to 4%
and a smoke spot value of 1 or less. Maintaining O
2
in the 3 to 4% range assures that there are no
unburned hydrocarbons remaining in the exhaust. Unburned hydrocarbons cause soot production.
If the above values cannot be obtained by adjusting the Burner air band and shutters alone, it may be
necessary to reduce the firing rate (lower fuel pressure and/or install a smaller nozzle). This is especially
true at elevations above 3,000 ft (914 m).
3.2.1.1. Fuel Pressure Adjustment
1. Disconnect the fuel Quick-Connects.
2. Remove the ¼ in. pressure tap plug located on the top of the Burner fuel pump.
3. Install an adapter to facilitate using a 0 to 300 psi pressure test gauge. Do
not use pipe dope.
4. Connect the fuel Quick-Connects.
5. Turn the BURNER Switch ON.
6. The Burner will begin a 15 second pre-purge. Monitor the fuel pressure during the pre-purge and
make adjustments using the fuel pressure adjusting screw. (Refer to Appendix A-26)
7. Turn the adjusting screw clockwise to increase fuel pressure or counter clockwise to decrease fuel
pressure until it is stable at 150 psig.
8. Once the fuel pressure is set, proceed with air setting and adjustment.
3.2.1.2 Air Setting and Adjustment
Air Band and Shutter may be opened or closed in amounts sufficient to adjust exhaust 0
2
levels as
sampled using a combustion analyzer. (Refer to Appendix A-26)
3.2.1.3 O
2
Content Sampling
1. Follow the combustion analyzer manufacturer’s instructions for pre-purge and exhaust sampling.
2. Sample the exhaust gas
by inserting the combustion analyzer sampling probe into the chimney
access hole provided through the exhaust guard. The
probe must be greater than 5 in. (127 mm) in
length
for an accurate sampling. Exhaust O
2
content must be 3 to 4% for optimum performance and
minimum soot production.
3. Several samples should be taken as the heater warms. The final sample should be taken just before
the heater reaches 180ºF (82.2ºC).
3.2.1.4 Smoke Spot Sampling
1. Follow the smoke spot tester manufacturer’s instructions for accurate exhaust sampling.
2. Sample the Burner exhaust for smoke
by inserting the smoke spot sampling probe into the chimney
access hole provided through the exhaust guard. The
probe must be greater than 5 in. (127 mm) in
length
for an accurate sampling. Smoke spot production must be 2 or less.
3.
Several samples should be taken as the heater warms. The final sample should be taken just before
the heater reaches 180ºF (82.2ºC).
NOTE: Higher O
2
percentage (excess air settings) lowers soot production but raises stack temperature
and reduces efficiency. Lower O
2
percentage (inadequate air settings) increases efficiency and
lowers stack temperature but may cause soot build-up. A Burner optimized for clean and efficient
operation will have O
2
levels of 3 to 4% and a smoke spot value of 1 or less.
4. Loosen the air band and shutter locking screws enough to provide movement for adjustment. (Refer
to Appendix A-26)
5. Start the Burner by turning the BURNER Switch ON. The Burner will start and begin a 15 second
pre-purge followed by the ignition sequence.