P-K SONIC
®
Gas Fired Boiler
Technical Service 1.877.728.5351
Revised: June 2, 2017
Released: June 2, 2017
HARSCO Industrial, Patterson-Kelley 2017
All Rights Reserved.
1004905978 P-K SONIC NURO Installation and
Owners Manual (Rev F Jun-2017).docx
Page 41
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
The bo
iler 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 SONIC
®
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
an integrated test port. This port is located on the upstream side of the valve body for measuring
supply pressure.
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
NOTE
Make sure to re-open the main gas cock (external to the boiler) after a successful test.
NOTE
Make sure to re-open the downstream gas cock (inside the boiler) after a successful test.
Gas Valve w/ Test Port