Munters HCUw, Operating & Maintenance

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Trouble shooting:
Service, maintenance, and cleaning are to be done only by a qualified service person.
Thermostat calls for heat but:
The exhaust blower does not start:
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No power to appliance.
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Lose wire, either 24 volts or 115 volts side.
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Defective relay.
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Defective motor.
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Something caught in the blower wheel.
The exhaust blower starts, but the HSI does-not start to glow:
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Flue vent blocked, and pressure switch is not being activated.
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High temperature hose from the exhaust blower` to the pressure switch is loose
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Roll out and limit switches have opened because of excessive temperatures.
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Loose wire on either the 24 volt or 115 volt side.
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Defective ignition module.
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Broken HSI.
The HSI glows, but no gas:
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Loose wire to the gas valve from the ignition module. Defective ignition module or gas
valve. Closed manual gas valves outside of the appliance.
Gas valve opens, HSI glows, but gas does not ignite:
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Incorrect inlet or manifold gas pressure.
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HSI not in correct position.
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Burners or burner orifices closest to HSI are blocked with debris, dirt, etc.
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Voltage to appliance is in excess of 127 volts and exhaust blower is "pulling" too much air.
Only a few burners light:
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Carry over ports, burners, or burner orifices are blocked with debris, dirt etc.
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Voltage to appliance is in excess of 127 volts and exhaust blower is pulling too much air.
Burners light, but do not stay lit:
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Sensor is not in correct position.
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Sensor wire loose.
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Unit not grounded.
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Sensor is broken, or covered with dirt.
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Ignition module is defective and turning the gas valve off. Roll out switches or limit switches
are being activated.
Flame does not go down the tubes, but "rolls out" and activates the roll out switches:
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Flue vent is blocked and not creating enough suction on the burners. Heat exchanger tubes are blocked with
debris, dirt, etc. Burners are blocked with debris, dirt, etc.
The limit switch is activated:
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Circulating air blower is not operating.
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Filters are clogged.
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Closed or blocked vents in the building.
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There is less than 4,250 cubic feet per hour of circulating air.