Patterson-Kelley Thermific, Installation & Owner'S Manual

Page: 29 / 46

Thermific
®
Gas-Fired Boiler Maintenance
Page 25
Low Air
If the "Low Air" indicator remains on for longer than
10 seconds, there is insufficient airflow through the
burner. Check that the burner is clean ("Cleaning the
Burner", Section 5.2) before adjusting the air inlet
damper (see "Air Flow Adjustment," Section 3.12.3).
A low air indication does not necessarily mean that the
low air switch is defective.
Ignition Failure
In the event the pilot flame is not detected by the UV
scanner during the 10 second trial-for-ignition period
(Step 8), the pilot gas valve and spark ignition are de-
energized. At this time a safety lockout occurs which
de-energizes all outputs from the programmer except
Terminal A, which is connected to the "Flame Failure"
indicator. A manual reset of the programmer (located
inside the control panel) is required when a safety
lockout occurs.
Flame Failure
In the event of a flame failure during a firing period,
the main fuel valves are de-energized and the pro-
grammer immediately returns to Step 7 or goes into a
"lockout" mode (see next paragraph). After the spark
ignition is re-energized and the pilot valve is reopened,
the 10 second trial-for-ignition begins again. If flame
failure occurs during a trail-for-ignition, a safety lock-
out occurs (see Ignition Failure). If flame failure oc-
curs and the indicator is illuminated, the programmer
must be manually reset.
Because of special requirements of some insurance or
local codes, the boiler may be equipped with a flame
safeguard programmer that will NOT re-cycle after
either a pilot- or main-flame failure, but will, instead,
go into a "lockout" mode. This mode requires that the
programmer be manually reset.
IMPORTANT
If any “Manual Reset” limit device trips,
DO NOT
reset without determining and correcting the cause.
(Flame safeguard, high or low gas pressure,
high temperature limit, stack temperature)