Desa DNV40NB - Manual (Page 18)

18 201835
DIRECT-VENT NATURAL GAS HEATER
DYNAVENT ®
www.desatech.com
OBSERVED PROBLEM
Ignition failures
Excessive noise
Main burner will not cycle off
Furnace will not operate
POSSIBLE CAUSE
5. Burner cycles off and glo bar comes on
immediately, check the following:
1. Blower out of balance
2. Motor hums
1. Thermostat setting
2. Gas valve stuck open
1. Wiring connections or shorts
REMEDY
5. A. Check flame sensing probe. Be sure
probe is positioned in the burner
flame and glowing cherry red. Check
wire and wire connections at probe
and ignition control
B. If wire and wire connections okay,
check for voltage across brown and
orange wires at ignition control. If
no voltage, replace ignition control
C. If voltage present, check wiring and
wire connections at valve
D. If wire and wire connections okay,
replace valve
1. Replace blower
2. Replace motor
1. Check thermostat
2. Check gas valve. If stuck open, replace.
Do not attempt to repair valve!
1. Check all wiring to assure proper con-
nection or detect possible shorts
TROUBLESHOOTING
Continued