PAGE 41 of 84 HU-SOUTHWEST-1480 GAS-FIRED HUMIDAIRE UNIT
© SAMUEL JACKSON, INCORPORATED 2005 ALL RIGHTS RESERVED
INTERFERENCE TEST
Operation of the ignition transformer and spark plug is checked here. Electrical
interference between the spark plug wire and flame rod wire is also checked.
The moist air fan must be running at least 20 seconds before you are able to access this
screen. Operation of the fan is verified by both the Air Flow Switch (AFS) and the Fan
Interlock Relay (FIR) being satisfied.
Touch the IGT button. The green light should remain green at all times. If it is quiet in
the gin, you should hear the hiss of the spark. The spark electrode gap should be between
1/16 and 1/8 inch (1.5 to 3mm).
If the light turns red indicating interference, check the path of the spark plug wire from
the ignition transformer to the burner head. This 6,000 Volt wire may be too close to the
flame rod wire. It is ok to run them together for a short distance through the metal conduit
to the burner. It is not ok to coil the spare length of wires together. Since the operating
program makes a similar test during each trial for ignition, the burner will not operate
until this problem is corrected.
TEST FOR IGNITION
This step allows adjustment of the manual gas low fire valve. Air volume through the unit
and the air shutters should already be set before adjusting the low fire valve.
With the moist air fan on, the spark plug fires continuously until the OK button is pressed
after the flame is established and the low fire valve is adjusted. Adjust the low fire valve
for easy ignition but not too far open that a large flame exists at low fire if the “PV
ALWAYS OPEN” option is used. Too big a flame at the low fire position will result in
the actual air temperature overshooting the setpoint temperature while the pump is off
and unit is idling.
See “Additional Settings” section of manual for more information on the PV ALWAYS
OPEN and PV OPEN TO LIGHT ONLY settings.
If “PV ALWAYS
OPEN” setting is used,
it is very important to
adjust the manual gas
low fire valve open
just enough for easy
ignition.
If “PV OPEN TO
LIGHT ONLY”
setting is used, this
valve can be set wide
open for easy ignition.
