Nortec GS Series - Manual (Page 51)

GS Series Installation | 48
Service Checks
Combustion Blower
The combustion air blower motors are permanently lubricated and do not require lubrication. Clean out any
dust that has accumulated in the blower housing using an air gun.
Burner
The combustion air blower motors are permanently lubricated and do not require lubrication. Clean out any
dust that has accumulated in the blower housing using an air gun.
Flame Sensor
Flame current is the current which passes through the flame from the sensor to ground. The ignition module
must detect a minimum flame current of 0.7 microamps or a flame proving lockout will occur. To measure
flame current, connect a DC micrometer to the FC- FC+ terminals on the module. Meter should read 0.7 uA
or higher. If meter reads below “0” on scale, meter leads are reversed. Disconnect power and reconnect
meter leads for proper polarity.
NOTE: Proper polarity of supply voltage to the unit is necessary for flame sensing to occur. Oxidation on
flame sensing rod can reduce measured current. The oxidation can be cleaned from the sensing rod using
steel wool or an emery cloth.
Igniter Check
If the igniter is suspected of being defective then the following test may be carried out;
Ensure that the power and gas is switched off before servicing.
To test the igniter, disconnect the igniter leads from their terminal connections.
Using a multimeter set the Ohm’s scale and place one of the meter leads on one of the igniter wire ends and
the other meter lead on the end of the other igniter wire.
Gas Valve Setting
The gas valves used in the GS Series humidifier are negative-pressure-regulated valves. The valve setting
listed on the product rating plate is shown relative to atmosphere – this setting will always remain constant.
The valves come preset from the factory for the correct gas type. If an adjustment is required, use the
following steps:
Remove the screw from the pressure port marked “out” on the back side of the gas valve.
Connect a hose from a digital manometer (or an inclined manometer capable of reading below 0.1”w.c.) to
the “out” pressure port.
Activate the humidifier and measure the gas valve pressure once the valve is energized and a flame is
established in the combustion chamber. Verify this pressure to the pressure listed on the unit specification
label.
If the pressure needs adjusting, remove the locking cap on the top of the gas valve.
Below the locking cap is an adjustment screw. Increase the pressure by turning the adjustment screw
clockwise, decrease by turning counter-clockwise.
NOTE: The pressure will fluctuate slightly as the unit operates, especially with very sensitive measuring
devices. Use the mean pressure value as the set pressure.
Once the pressure has been adjusted, replace the locking cap.
Replace the screw in the “out” pressure port and tighten firmly.