Supplemental Manual
24
HE+ Series 1-Stage Supplemental Manual
If at any time the main valve fails to close completely and maintains a flame, the full time flame
sense circuit will detect it and energize the combustion blower. Should the main valve later close
completely removing the flame signal, the combustion blower will power off following the optional
post purge period.
The Fenwal DSI Control 24 VAC Tube Heater (905000020) is not position sensitive and can be
mounted vertically or horizontally. The case may be mounted on any surface with #6 sheet metal
screws. All wiring must be done in accordance with local and national electrical code. Refer to wire
diagram page 35 when connecting 905000020 to other components in the burner.
The Fenwal DSI Control 24 VAC Tube Heater
(905000020) uses voltages of shock hazard po-
tential. Wiring and initial operation must be done
by a qualified service technician. The control
must be secured in an area that will experience
a minimum of vibration and remain below the
operating temperature of 160ºF. All connec-
tions should be made with UL approved 105ºC
rated 18 gauge, stranded, .054 thick insulated
wire. Refer to wire diagram page 35 when con-
necting the Fenwal DSI Control 24 VAC Tube
Heater (905000020) to other components in the
burner.
Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper
and dangerous operation. A functional checkout of a replacement control is recommended.
Proper location of the electrode assembly is important
for optimum system performance. The electrode assem-
bly should be located so that the spark gap is inside the
flame envelope about 1 inch (2.5 cm) from the base of
the flame at the burner cup.
Electrodes should have a gap spacing of 3/16” (0.188” ±
0.031” or 4.76 mm ± 0.81 mm). If this spacing is not correct, the assembly must be adjusted or re-
placed. DO NOT adjust the curved igniter/sensor prong. Adjust/bend only the ground prong (also
see next page).
TH Thermostat Input
1/4”
PSW Pressure Switch Input
1/4”
V1 Valve Power (MV)
1/8”
IND
Inducer Blower Output
1/4”
NC
Alarm (Not used)
-
L1 120/240 VAC Input (Hot)
1/4”
24 VAC 24 VAC Supply to Processor
1/4”
V2 Valve (MV)
1/8”
GND Valve & System Ground
1/8”
Spark Spark & Local Flame Sense 1/4”