P-K MACH
®
Gas Fired Boiler
Technical Service 1.877.728.5351
Revised: January 3, 2020
Released: January 3, 2020
Patterson-Kelley 2020
All Rights Reserved.
1004905981 P-K MACH C1500H-C4000 Installation and
Owners Manual (Rev F Jan-2020).docx
Page 69
Next, check for obstructions of the combustion air intake and/or exhaust (flue) piping. Next, check the
hoses leading to the air switches are not kinked or obstructed. An error related to the air switch does
not necessarily mean that the air switch is defective.
When 66:
“Interrupted Airflow Switch ON”
is displayed, check that the air switch is open when the
blower is offline. Ensure there is no air flow through the boiler when the blower is offline. An excessive
negative draft in the flue piping can cause air flow through the offline boiler which may be strong
enough to maintain closure of the air switch.
When 65:
“Interrupted Airflow Switch OFF”
is displayed, check that the air switch is closed when the
blower is running. If the air switch does not close within 5 minutes during purge, the boiler locks out.
Check that the burner is clean (Section
) and that there are no obstructions to airflow in the intake or
exhaust ducts.
6.6.6 Flame Failure
In the event of a flame failure, the NURO control may display one of the following error messages:
•
106:
“Flame Lost in Main Flame Establish Period”
•
107:
“Flame Lost Early in Run”
•
108:
“Flame Lost in Run”
•
109:
“Ignition Failed”
•
110:
“Ignition Failure Occurred”
When 109:
“Ignition Failed”
or 110:
“Ignition Failure Occurred”
is displayed, the boiler did not light
during the trial for ignition. Check that the ignition electrode, ignition wire, and gas valve are functioning
properly. Check that the direct spark ignition is visible through the flame observation port during the
trial for ignition.
When 106:
“Flame Lost in Main Flame Establish Period”,
107:
“Flame Lost Early in Run”
, or 108:
“Flame Lost in Run”
is displayed, the boiler lost the flame signal during operation. Check that
combustion is adjusted properly, the gas pressure is correct, and the ignition electrode, ignition wire,
and the gas valves are functioning properly.
6.6.7 Flame Error
In the event of a flame error (premature or late flame signal), the NURO control will display 105:
“Flame Detected Out of Sequence”
. This may be caused by a failed/leaky gas valve or a flame rod
or ionization rod malfunction. If gas valve leakage is suspected, the unit must be isolated by turning off
the main gas supply line. Lockout/tagout the boiler until qualified and knowledgeable service personnel
are available to evaluate and repair or replace the failed parts. Check that the incoming gas pressures
have not exceeded 14” W.C. (1/2 psig).
6.6.8 Flue Problem
When the normally-closed high exhaust back pressure switch opens, the NURO control will display
10013:
“High Back Pressure Limit”
. This may be caused by an obstruction in the flue piping, an
obstruction in the combustion air intake, or a blocked condensate system. When the blockage is
removed, the boiler will automatically restart. If no blockage is found, it may be necessary to replace
the high exhaust back pressure switch.
