Lennox EL195UHNE Series Manual page 11

4. Gas Valve (Figure 6)
The EL195UHNE uses an internally redundant valve to
assure safety shut-off. If the gas valve must be replaced,
the same type valve must be used.
24VAC terminals and gas control switch are located on top
of the valve. All terminals on the gas valve are connected
to wires from the ignition control. 24V applied to the termi-
nals opens the valve.
Inlet and outlet pressure taps are located on the valve. A
manifold adjustment screw is also located on the valve. An
LP/Propane changeover kit is available.
GAS VALVE
NEGATIVE AIR
PRESSURE PORT
INLET
SUPPLY
PRESSURE
TAP
FIGURE 6
POSITIVE AIR
PRESSURE PORT
OUTLET
MANIFOLD
PRESSURE TAP
Page 11
5. Flame Sensor (Figure 5)
A flame sensor is located on the top of the air gas plenum.
The sensor can be removed for service without remov-
ing the the burner. During operation, flame is sensed by
current passed through the flame and sensing electrode.
The SureLight control allows the gas valve to remain open
as long as flame signal is sensed. To check flame sense
signal use the push-button found on the integrated control
and go to Field Test Mode. The menu will display the flame
signal. See table 6 for flame signal.
TABLE 6
Flame Signal in Microamps
Normal
2.6 or greater 2.5 or less
6. Ignitor (Figure 5)
EL195UHNE units use a nitride ignitor made from a pro-
prietary ceramic material. To check ignitor, measure its
resistance and voltage. A value of 39 to 70 ohms indi-
cates a good ignitor. Voltage to the ignitor should be 102
- 132VAC. See figure 7 for resistance and voltage checks.
Low Drop Out
1.1