1
PFG S
erieS
7 G
aS
-
Fired
W
ater
B
oiler
– U
niverSal
C
ontrol
S
yStemS
Part Number 550-110-643/0605
TABLE III: Pilot Lights, Main Valve Will Not Come On
With or Without Vent Damper
Correct wiring.
Make sure sense wire is not wrapped
around any pipe or accessories.
Is sense wire securely attached to sense
terminal and pilot assembly?
No
Yes
Correct.
Replace pilot
assembly.
Replace
valve.
Check for continuity of sense wire
and condition of insulation.
Not OK
OK
Check for proper gas pressure, clean pilot assembly
tight mechanical and electrical connections.
Also check for proper system grounding.
See additional information on page 15.
Does spark stay on for more than a few seconds after pilot is established?
No
Yes
Is sensing probe ceramic
cracked?
No
Yes
Replace pilot
assembly.
Is sense wire or sensing
probe shorted out to
metal surface?
No
Yes
Correct.
Replace ignition control.
Replace ignition
control.
Is 24VAC between Terminals
MV and MV/PV on ignition control?
No
Yes
Contact gas supplier to
correct.
Is inlet gas pressure at least
5.0"W.C. and not over
14"W.C.?
No
Yes
Is main valve wiring secure
at terminals?
No
Yes
No
Yes
Does system have proper flame signal?
Set up microammeter to measure
output current in flame sensor circuit
as follows:
a. Detach sense lead from ignition
control. Attach negative lead
from microammeter to sense
terminal on ignition control.
b. Attach positive lead to sense wire
from pilot assembly.
c. Disconnect main valve lead from
Terminal "MV" on ignition control.
d. Energize the system. Spark should
ignite the pilot. As soon as pilot is
burning, microammeter should
read at least 1.0 microamp for
Honeywell S8620C, 0.1 microamp
for U.T. 1003-510.
e. Is flame current signal less than the
minimum specified in "d" above?