Portable Dryer Troubleshooting
39
The B. GND terminal is used to ground the burner and to complete the flame current signal circuit. This terminal is
new for systems that used the older version of the Fenwal board. This terminal must be connected to the burner
(chassis) ground not only to ensure the best, long term, stable flame signal, but also to ground the burner for
proper sparking.
The use of a burner ground terminal eliminates the problem of loss of flame sense signal due to a missing or loose
neutral or ground (green) wire at the 120 VAC power source. The new board has been designed such that reversing
the polarity of the 120 VAC line does not cause a loss of flame signal. Thus providing a more reliable flame signal
along with a reduction of nuisance lockouts, due to its design and the use of the B. GND terminal.
New Fenwal Board Wiring
L2
V2
(B) V1
S1
E2
GAS
VALVE
H.V.
E1
120
VAC
BURNER
NEU.
HOT
L2 GAS
VALVE
120
VAC
NEU.
HOT
V2
L1
V1
NC
BURNER
H.V. S1
B. GND
IGNITOR
Part No. HF-4624
Flame Safety Board
BURNER
GROUND
(B. GND)
Old version with Remote Flame Sense. New version with Remote Sense using existingspark and remote sense electrodes.FLAME ROD
Note that terminal E2 on the old version has been replaced by terminal B.GND on the new board.
(A) L1
Wiring Reference