11
PYROMASTER
®
UVHB20 Vent-Free Heaters
20001540
Troubleshooting - Honeywell VS8421
•
Supply line hooked up
•
Shutoff valve open
•
Lockout has engaged. Wait 60 seconds, try
again.
•
For spark at electrode while depressing
Piezo - 1/8" gap to pilot hood needed.
•
All wiring connections
•
Replace Piezo ignitor
•
For air in the lines
•
Thermopile needs a minimum 325mV.
Adjust pilot flame height.
•
All wiring connections
•
Replace Thermopile
•
Thermocouple needs a minimum of 14mV.
•
Defective valve. Turn to pilot, meter should
read greater than 100mV. If not, replace.
•
Valve is turned ON.
•
Wall switch is not turned ON. Watch for
grounded wires!
•
Themopile needs a minimum 325mV.
•
Plugged burner orifice.
NO
NO
START
CHECK
NO
NO
Gas Supply On
YES
Pilot Lights with
Piezo Ignitor
YES
Pilot Stays Lit
YES
Pilot Lights
Main Burner
YES
System OK
