Air Flow Adjustments; Gas Valve Setup And Adjustment - Patterson-Kelley MACH Series Installation & Owner's Manual

MACH® Series Gas-Fired Boiler
valve body for measuring supply pressure. (See figure
below.)
Test Port
The supply pressure during main burner operation
must be greater than the minimum indicated on the
rating plate (3.5". W.C. for natural gas, 7" W.C. for
propane).

3.12.3 Air Flow Adjustments

The air flow is pre-set at the factory prior to shipment.
In unusual situations the air/gas ratio may have to be
adjusted to obtain proper combustion readings for
specific local conditions.
Combustion measurement instrumentation must be
used to adjust the boiler for local conditions (See
instructions below). Adjust the carbon dioxide (CO
or oxygen (O ) reading to achieve conditions as listed
2
in the following Table 3-1.

3.12.4 Gas Valve Setup and Adjustment

Required Tools:
•
2 mm hex wrench
•
Slotted screwdriver
•
Combustion analyzer
Gas Pressure Test Port
)
2
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Note:
Verify gas pressure at inlet to boiler is in
accordance with Table 3-1 below. Gas flow is
dependent primarily on fan speed not upstream gas
pressure. When set up for natural gas operation, the
boiler is capable of operating with gas supply
pressure as low as 3.5" W C.
Each MACH® Series boiler is equipped with two
combined gas/air control and gas safety shut off
control valves. The valves function in parallel with
the variable speed combustion blower to supply the
correct gas air ratio for optimum performance and
efficiency. The combustion blower speed is
controlled automatically and determines the amount
of negative pressure felt at the gas safety shut off /
control valves. The gas valve servo regulators adjust
gas flow for each valve to maintain zero pressure at
the outlet nozzle of the associated valves.
Boiler Test Mode:
The test mode should be used when checking and
setting the gas safety shut off / control valves on the
MACH® Series boiler series boilers. In this mode an
automatic heat request is simulated as follows:
Test Mode High:
Simultaneously pressing the "Mode" button and the
"+" button for 3 seconds activates the "Test Mode
High" function to drive the boiler output to
maximum. The display will blink and indicate "H" in
the first digit of the display to indicate the boiler is
being driven to the maximum output rating. This test
mode will automatically terminate after 15 minutes or
can be terminated from the control/display panel by
simultaneously pressing the "+" and "-" buttons for
three seconds.
Test Mode Low:
Simultaneously pressing the "Mode" button and the
"-" button for 3 seconds activates the "Test Mode
Low" function to drive the boiler output to minimum.
The display will blink and indicate "L" in the first
digit of the display to indicate the boiler is being
driven to the minimum output rating. This test mode
will automatically terminate after 15 minutes or can
be terminated from the control/display panel by
simultaneously pressing the "+" and "-" buttons for
three seconds.
Installation