American Aldes DHV-150H Defrost Thermostat, Electric Ventilation Damper, Condensate Pump Kit

5.7B Programmable Ventilation Timer

The ventilation timer controls the fan and the motorized fresh air damper. When the ventilation timer is activated, the central conditioning unit will circulate the indoor air, and bring in fresh air from outside. The ventilation timer should be set for the required ventilation of the residence. The home should be ventilated with fresh air as suggested by applicable codes and standards.

If the DHV-150H fails to ventilate as expected, check that the time on the timer is correct. For the timer to carry out the program schedule, the slide switch in the upper left corner on the timer must be set to “AUTO”. The slide switch in the upper right corner of the DHV- 150H must be set to “RUN”. Also check the programs on the timer to be sure that the timer is calling for ventilation at the correct times. If the timer fails to operate or operates erratically, reset the timer; see section 3.5 of this manual.

5.8 Defrost Thermostat

The defrost thermostat is attached to the refrigerant suction tube between the accumulator and the compressor. It will automatically shut the compressor off if the low side refrigerant temperature drops due to excessive frost formation on the evaporator coil. The fan will continue to run, causing air to flow through the evaporator coil and melt the ice. When the ice has melted, the evaporator temperature will rise and the thermostat will restart the compressor.

5.9 Electric Ventilation Damper

The ventilation timer controls the electric ventilation damper. The damper will open when the ventilation timer is activated to allow fresh air into the structure through the 6” diameter fresh air inlet duct. The electric ventilation damper will remain closed when the ventilation timer is not activated to prevent over- ventilating the structure when the unit is dehumidifying or recirculating the indoor air.

The electric ventilation timer operates on 24 Vac from the control circuit. DO NOT connect high voltage to the

damper motor or damage to the motor may result. DO NOT force the blade of the damper by hand or damage to the damper motor may result.

If the electric ventilation damper fails to operate:

1.Check that the wiring is correct and that voltage is present at the damper motor.

2.Check for any obstruction inside the damper.

If the electric ventilation damper fails to operate after performing these checks, it must be replaced.

5.10 Low Pressure Control

If the low side refrigerant pressure drops to 15 PSIG, the low-pressure control opens and shuts off the compressor and fan. It is an automatically reset control. It will close when the refrigerant pressure rises to 35 PSIG. Its primary function is to prevent damage to the compressor if a leak develops in the refrigeration system. It may also open if the unit is A) installed in a cool area (below 50 F) or B) installed where it is below 40 F and then started. Under these conditions, the unit will restart within several minutes. Until the unit warms up, it may cycle several times.

5.11 Condensate Pump Kit

An optional condensate pump kit is available from the factory for use with the DHV-150H. Condensate is automatically pumped to a remote location when the water level in the pump's reservoir rises to close the float switch.

The pump also contains a safety float switch. The white leads from this switch extend from beneath the pump cover. This switch should be installed in series with the field wire that connects the blue (#5) lead from the DHV-150H to the blue (#5) lead on the control panel.

If the pump fails, this switch opens the compressor control circuit and stops water production before the reservoir overflows. The DHV-150H will continue to ventilate or circulate air as normal, but will not dehumidify until this switch closes.

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