Robertshaw 780-704 - User Manual

TROUBLESHOOTING GUIDE
780-704/780-705
MODERNIZATION KITS
SEQUENCE OF OPERATION AND SYSTEM CHECKOUT
PROCEDURES
The inial installaon poron is now complete and ready for nal
system checkout. The checkout procedures listed below must be
followed. While there are redundant safety features built into the
system, it is imperave that you follow the steps outlined below to
ensure proper and safe operaon. If you encounter any irregularies,
refer to the TROUBLESHOOTING GUIDE
1. ❏ Check all wiring connecons.
2. ❏ Turn on main gas supply and manual valve on the gas valve.
3. ❏ Turn on electrical power.
4. ❏ Thermostat set high.
5. ❏ Sparking begins, pilot gas ignites.
6. ❏ Pilot ame on sensor, main burner on.
7. ❏ With main burner on, cycle thermostat off then on.
A. Nonlockout system will turn o and immediately on again.
B. Lockout system will turn o. Sparking will not begin for 5
seconds.
8. ❏ With the main burner on, turn the manual gas valve to off
posion. Wait unl all ame is out. Turn manual gas valve
on again.
A. Sparking will begin as soon as the pilot ame is out.
B. Pilot ignion takes place when gas ow is restored.
9. ❏ If this is a lockout system, with main burner on, turn manual gas
valve o. Sparking will begin when the pilot ame goes out. Aer
60 seconds the system will lockout and sparking will cease.
10. ❏ To restart the system turn thermostat low for 5 seconds. Then set
high again. Sparking will begin in 5 seconds.
11. ❏ It is absolutely necessary that the system be cycled normally
(thermostacally controlled) through at least three complete
heang cycles. Set thermostat to a temperature slightly higher
than the exisng ambient. Allow appliance to cycle ON and run
through a normal cycle. Do not manually shorten the cycle.
12. ❏ The inial checkout procedures have been completed. If the
system has funconed normally, return thermostat seng to its
normal seng. The qualied installing agency must completely ll
out and apply the yellow appliance conversion scker to the front
of the appliance. Leave these and all other instrucons with
the homeowner.
TROUBLESHOOTING GUIDE
FLAME RECTIFICATION IGNITION CONTROL UNITS
SP715/SP735
THERE ARE FIVE POTENTIAL PROBLEM CONDITIONS WITH THE
THERMOSTAT SET HIGH:
1. Thermostat on, no spark, no pilot gas.
2. Have spark, no pilot gas ow.
3. Have pilot gas, no spark.
4. Have pilot ame, main burner does not turn on.
5. Short-cycling of main burner. Main burner turns o before the
thermostat is sased.
TO PERFORM THE FOLLOWING TEST YOU WILL NEED
A VOLT OHM METER.
PROBLEM #1: Thermostat on, no spark, no pilot gas.
Possible Causes
A No main power
B. Faulty transformer
C. Faulty thermostat
D. Faulty limit
E. Faulty ignion control unit
SOLUTION:
1. With power on and thermostat set high, set your test meter to the
24 volt scale. Probe terminals TH and TR. If you do not read 24 volts,
the problem is not in the ignion system. Perform normal system
checks of main power, transformer, thermostat and the limit control.
If you do read 24 volts at TH and TR the problem is in the ignion
system. Check for loose or defecve wiring. If wiring is good replace
the ignion control unit. See your Uni-Line wholesaler for order
numbers.
PROBLEM #2: Have spark, no pilot gas ow.
Possible Causes
A. Main gas supply turned o
B. Manual valve on gas valve turned o
C. Faulty primary valve in the gas valve
D. Faulty wire connecon
E. Faulty ignion unit
SOLUTION: Set test meter to 24 volt scale.
1. Be sure main gas valve and manual valve are turned on.
2. With gas on and the system sparking probe terminal TR and the blue
wire terminal on the solenoid on the 7000 gas valve. With 24 volts at
these terminals and pilot gas does not ow, replace the solenoid in
the 7000 gas valve.
3. If you do not read 24 volts at the solenoid valve terminals, probe
terminals PV and MV/PV on the ignion control unit. If you read 24
volts here but not at the gas valve, there is a loose wire connecon
in the blue or white wire. Repair the wire connecon.
4. If you do not read 24 volts at terminals PV and MV/PV replace the
ignion control unit.

Robertshaw 780-704 Specifications