TM 10-3510-209-24
3-22. WATER HEATER UV SCANNER AND FLAME SAFEGUARD ASSEMBLY (CONT)
TEST (Cont)
9.
Turn on load limit switch and check for 120 V ac
on terminals (23) and (24) of base terminal
board (10). If voltage is not normal, disconnect
power source and replace load limit switch (para
3-20, DISASSEMBLY, step 2). If voltage at
terminals 2 and 7 is normal, install flame
safeguard control circuit card (9) and two screws
(8).
NOTE
If the buzzer sounds, an ignition
failure is indicated.
NOTE
Unit maintenance has determined
that ignition takes place momentarily
but system shuts down immediately
after ignition.
10.
With multimeter set for dc operation, set load
limit switch to ON and press reset pushbutton
(11) and check voltage at test points (15) and
(16). If voltage is not 5 to 6 V dc, replace UV
scanner.
NOTE
Unit maintenance has determined
that ignition does not occur after
pressing reset pushbutton but buzzer
sounds.
11.
With multimeter set for ac operation, set load
limit switch to ON and check for 120 V ac at test
points (12) and (13) after pressing reset
pushbutton (11). If voltage is zero, replace
flame safeguard control circuit card (9).
NOTE
Callouts (23) and (24) are actually
terminals 2 and 7 respectively.
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