FloAire FAV-M - Manual (Page 34)

34
Maxitrol Preliminary Circuit Analysis Series 14 System
The basic Series 14 system consists of an amplifier, a discharge-air sensor and mixing tube, a remote-
temperature selector, and a modulating valve or a modulator-regulator valve.
Series 14 Preliminary Wiring Testing Procedures:
•
Disconnect the discharge-air sensor and replace with a 10,000-Ohm, 1/4-watt test resistor at
Terminals 3 & 4.
• Connect a dc-volt meter on the modulator-regulator or modulator-valve terminals.
• Set the temperature to 55° F. Voltage should read 0-V.
• Rotate dial to 90° F. Voltage should gradually increase to a minimum of 20-V.
•
If these voltages are obtained, the valve function can now be checked out.
•
In the event proper voltages are obtained, and the valve responds correctly to these voltages, the
problem could be in the wiring to the discharge-air sensor or the discharge-air sensor itself.
•
If the proper voltages are not obtained when wired as shown above, the problem can be isolated to
the electronics.
After these preliminary tests are completed, remove the test resistor and reconnect the discharge air
sensor to Terminals 3 and 4 and continue checking system, following the Series 14 Troubleshooting
Steps.
The operation of the modulating-valve regarding voltage is as follows:
o 0 to 5-V The heater should be at bypass or low.
o 5 to 15-V The heater should respond to various input rates.
o 15-V and up The heater is at maximum input.
•
If the voltage is obtained on the valve terminals, but the heater does not respond as described, the
problem can be isolated to the valve itself or to the gas-control manifold of the heater.