Harsco Patterson-Kelley MACH Series, Инструкция по установке и эксплуатации

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MACH® Series Gas-Fired Boiler
29
Gas Valve
The second test mode checks the fan rate with the burner off at high speed or at low speed.
These test modes will automatically terminate after 15 minutes of inactivity or can be terminated from the
control/display panel by pressing the cancel/reset button
3.11.2 Fuel/Air Adjustment
The MACH
®
C2500 boilers are equipped with a gas/air ratio control valve and a gas safety shut off control valve,
combined into one valve assembly. The valve functions in series with the variable speed combustion blower to supply
the correct gas air ratio for optimum firing performance and efficiency. The combustion blower speed is controlled
automatically by the boiler controller. The blower speed determines the amount of air flow and the amount of
suction/negative pressure at the gas valves. The gas valve adjusts gas flow to maintain the proper delivery pressure
at the outlet of the valve.
NOTICE!
Adjustments shall only be performed by qualified and knowledgeable installer or service agency
specifically trained and certified to perform maintenance and/or startup on the Patterson-Kelley MACH
®
boiler.
3.11.2.1 Gas Pressure Adjustment
See rating plate for the minimum and maximum gas pressure of the boiler.
The supply pressure during main burner operation must be greater than
the minimum indicated on the rating plate. 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 left.)
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
automatic gas valve may have to be adjusted to obtain proper combustion
readings for specific local conditions. A combustion analyzer must be
used. Combustion should be set in accordance with Table 3.1.
Table 3-1 Combustion Exhaust Reading For Setting Gas Safety Shut Off / Control Valves
Nominal High Fire Setting Low Fire Setting
Fuel
Gas Pressure % O
2
% CO
2
% O
2
% CO
2
Natural Gas
7" W.C 4.8 ± 0.2 9.2 ± 0.1 5.0 ± 0.2 9.1 ± 0.1
Propane Gas
11” WC 4.8 ± 0.2 10.4 ± 0.3 5.0 ± 0.2 10.3 ± 0.3
3.11.2.2 Combustion Setup and Adjustment
Set the combustion using the Service Menu BNR ON TEST HI & BNR ON TEST LOW modes. These test modes
should be used when checking and setting the gas safety shut off / control valves on the MACH
®
C2500 boiler. In this
mode a heat request is required. Once the boiler cycles on, use the arrow keys to access the Service Menu and
select the BNR ON TEST HI or the BNR ON TEST LOW mode and push enter. The boiler will ramp up to high or low
fire.