P-K Storm
TM
Gas Fired Boiler
Technical Service 1.877.728.5351
Revised: June 26, 2020
Released: June 26, 2020
©
Patterson-Kelley 2020
All Rights Reserved.
2691000273 P-K Storm ST2500-ST4000
Installation and Owners Manual Rev A.docx
Page 44
Gas Pressure Switch Tests
Low Gas Pressure Switch
The boiler is furnished with a
low gas pressure switch, installed near the boiler’s main gas
shutoff/control valve. The operation of this switch must be checked as follows:
1. Close the main gas cock (external to the boiler).
2. Cycle the boiler on by generating a heat request.
3. Allow the boiler to proceed through prepurge and attempt ignition.
When the main gas shutoff/control valve opens to attempt ignition, the low gas pressure switch will trip,
causing the NURO touchscreen to display 10012:
“Low Gas Limit”
. Even after re-opening the main
gas cock, 10012:
“Low Gas Limit”
will remain on the NURO display until the boiler is manually reset
by pressing “Reset Control”.
High Gas Pressure Switch
T
he boiler is furnished with a high gas pressure switch, installed near the boiler’s main gas
shutoff/control valve. The operation of this switch must be checked as follows:
1. Before starting the boiler, close the downstream gas cock located inside the
boiler’s enclosure.
2. Cycle the boiler on by generating a heat request.
3. Allow the boiler to proceed through prepurge and attempt ignition.
When the main gas shutoff/control valve opens to attempt ignition, the high gas pressure switch will trip,
causing the NURO touchscreen to display 10011:
“High Gas Limit”
. Even after re-opening the
downstream gas cock inside the boiler, 10011:
“High Gas Limit”
will remain on the NURO display until
the boiler is manually reset by pressing “Reset Control”.
3.11 Fuel/Air Adjustments
The P-K Storm
™
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 mixture 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.
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
NOTE
Make sure to re-open the downstream gas cock (inside the boiler) after a successful test.
Gas Valve
NOTE
Make sure to re-open the main gas cock (external to the boiler) after a successful test.
