Service manual

SERVICING
51
Power to System
Thermostat calls for heat
Control board applies power to
Air circulating blower (ACB)
cooling speed. Pilot and Igniter
are locked out.
"Smart Valve" internal check
(valve and igniter) OK?
"Smart Valve" powers Igniter,
opens pilot valve.
Pilot Lights, Valve Senses Flame
Igniter Off Main Valve Opens
Main burner Lights Smart Valve
sends signal (24V) to control
board.
Thermostat Ends "Call for Heat"
Main and Pilot Valves Close
Control board times out.
De-energizes power to blower
(
ACB
)
Pilot valve closes,
Igniter off.
Flame signal lost
Start
Self Check
Trial
For
Ignition
Main
Burner
Operation
End
Limit(s)
open
Limits closed
No
Igniter
opens
Board checks limit circuit
Yes
Control board times out, applies
power to blower (ACB) heating
speed.
Honeywell Smart Valve Sequence of Operation
SV9501
Flame signal detected
Pilot valve and Igniter remain
closed. Valve waits for flame
signal to disappear
Yes
Flame signal lost more
than 5 times in one call
for heat
Pilot and main valves close.
EFT (Electronic Fan Timer)
output de-energizes.
Five minute retry delay
Three second flame
Failure recycle delay
No
No
Yes
No
Yes
90 Second trial for ignition.
Ignter and pilot open, after
30 seconds igniter cycles off
pilot stays on. After 30
Seconds (60 from start),
igniter will cycle on for 30
seconds.
No
Yes