Slant/Fin Prodigy 21 KC-50 Installation And Operating Instructions Manual page 22

TROUBLESHOOTING: POSSIBLE CAUSES AND SOLUTIONS
DIAGNOSTIC "Continuous Flashing" - ELECTRONIC CONTROL FAILURE
Control board cannot be serviced. Replacement must be same manufacturer and model. After replace-
Electronic Control Is
ment, calibrate blower speed as shown in Part 3 in manual.
Defective.
CAUSE
High Limit Is
Set high limit above boiler water temperature (raise limit
Defective?
setting substantially as water temperature may be higher
than gage reading when there is no water flow through
boiler). Check for continuity across high limit contacts.
Circulator Not
With thermostat calling for heat, check for power to circu-
Running?
lator. If no power, check wiring connections to circulator.
Zone Valves Not
With thermostat calling for heat, check for power to each
Opening?
valve. If no power, check wiring connections to valve.
No Gas Supply To
Check that manual gas shutoff is open. Check for gas sup-
Gas Valve?
ply pressure to valve.
No Gas Supply To
Check gas valve knob in ON position. Check wiring and
Burner?
tubing connections to valve. Check for power to gas valve.
Note gas valve LED on control board (see page 21). Check
valve outlet pressure to determine if valve is opening (see
"How To Do It" on page 24).
Air-Gas Ratio Is Not
Check gas valve calibration as shown in Operation Proce-
Proper?
dures on page 16.
Orifice Sizing Is Not
Check gas and air orifice size (see Orificing Identification
Correct?
on page 25).
Electrical Connec- Check power wiring to electronic board, (hot wire to L1;
tions Are Loose or
neutral to L2) ground wire in junction box and to electronic
Reversed?
board.
Flame Sensor Check flame sensor current with microampmeter (see
Current Is Weak?
"How To Do It" on page 24).
Flame Sensor Is
Remove flame sensor from boiler (see "How To Do It" on
Defective?
Page 24). Check for cracked, wet ceramic insulator or bent,
burned, coated kanthal rod.
DIAGNOSTIC "3 FLASHES" - PRESSURE SWITCH PROBLEM
Electrical Wiring? Check wiring connections to pressure switch. Wires go to
Normally Open (N.O.) and Common (C) connections on
switch.
No Pressure Signal Check for loose, blocked tubing connections to pressure
To Pressure Switch? switch; loose blower hose connection; loose blower wheel.
Check for blocked air filter, vent terminal or vent tubing.
Blower Speed Not Check blower calibration as shown in Operation Proce-
Correct? dures on page 16.
Pressure Switch Is Check pressure switch calibration (see "How To Do It" on
Defective? page 24). Check that pressure switch contacts are open
(between N.O. and C) when blower is OFF.
22
DIAGNOSTIC "1 FLASH" - HIGH LIMIT OPEN 1 HOUR
TEST
DIAGNOSTIC "2 FLASHES" - NO IGNITION
(No Flame Signal After Trial For Ignition)
Refer to Replacement Parts information on
page 27 when parts need to be replaced.
SOLUTION
If contacts remain open, replace high
limit. Replacement must be same manu-
facturer and model. DO NOT set above
104°C (220°F).
If power OK, but circulator not running,
replace circulator.
If power OK, but valve not opening,
replace valve.
If no pressure, check for gas shutoff by
utility.
If valve not opening, replace valve.
Replacement must be same manufactur-
er and model. Calibrate new valve as
shown in Operation Procedures on page
16.
If pressure reading is incorrect, adjust gas
valve as shown in Operation Procedures
on page 16.
If size not correct, contact Slant/Fin Tech-
nical Services Department.
Correct all wiring connections.
If reading is below 1 microamp, continue
with "No Ignition" troubleshooting.
If defective, replace flame sensor.
Replacement must be same manufactur-
er, model and length.
Correct all wiring connections.
Secure all loose connections. Tighten
blower wheel set screw. Remove obstruc-
tions. Replace or clean filter.
If pressure readings are incorrect, adjust
blower speed as shown in Operation Pro-
cedures on page 16.
If switch is defective, replace switch with
same manufacturer, model and calibration.
Observe orientation of clear tubing con-
nections when replacing.