MACH® Gas-Fired Boiler
Page 34
3.11 B
URNER
A
DJUSTMENT
NOTICE! Adjustments shall only be performed by service representative specifically trained and certified
to perform maintenance on the Harsco Industrial, Patterson-Kelley MACH
®
boiler. Verify proper
operation after servicing.
See rating plate for the minimum and
maximum inlet gas pressure of the
boiler. The supply pressure during main
burner operation must be greater than
the minimum indicated on the rating
plate which is 3" W.C. for natural gas.
Nominal gas supply pressure is 7” W.C.
for natural gas. The gas pressure must
not exceed 14” W.C. which is the
maximum allowable pressure on the gas
train components. Each boiler is
furnished with a manual shut-off valve
which has an integrated test port. This
port is located on the upstream side of
the valve body for measuring supply
pressure. (See figure right.)
The air flow is pre-set at the factory prior to shipment. Gas flow is
dependent primarily on fan speed not upstream gas pressure. The air/gas
ratio may have to be adjusted to obtain proper combustion readings for
specific local conditions. A combustion analyzer must be used (see photo
left). Combustion should be adjusted in accordance with Table of
Combustion Exhaust Settings
NOTICE! For high altitude adjustments (greater than 2,000 feet above sea
level), see Section 8.3.
Fuel
Nominal
High Fire Setting
Low Fire Setting
Inlet Gas
Pressure*
% O
2
% CO
2
% O
2
% CO
2
Natural
Gas
7" W.C
5.7
8.7
5.9
8.5
Propane
11" W.C
5.7
10.0
5.9
9.9
Table of Combustion Exhaust Settings