Therma-Stor Products Group XT150H Remote Controls, 7.6C Replacing a Compressor, Nonburn Out

FOR HVAC INSTALLER ONLY

7.Evacuate the system with a good vacuum pump and accurate vacuum gauge. Leave the pump on the system for at least an hour.

8.Operate the system for a short period of time, monitoring the suction pressure to determine that the suction filter is not becoming plugged. Replace the suction filter/drier if pressure drop occurs. If a severe running burn out has occurred, several filter/driers may have to be replaced to remove all of the acid and moisture.

NOTE: NEVER use the compressor to evacuate the system or any part of it.

7.6C Replacing a Compressor, Nonburn Out

Remove the refrigerant from the system. Replace the compressor and liquid line filter/drier. Charge the system to 50 PSIG and check for leaks. Remove the charge and weigh in the refrigerant quantity listed on the nameplate. Operate the system to verify performance.

7.7 Remote Controls

The Ultra-Aire XT150H is controlled by devices mounted on a panel that is remote from the unit. You may or may not have the devices listed below depending on the model of the remote control panel you purchased. If the Ultra-Aire XT150H fails to operate as desired, always check the settings of the controls to insure that they are correct. Check that the controls are receiving 24Vac from the Ultra-Aire XT150H. Check the connections between the Ultra-Aire XT150H, the control panel, and the field control wiring.

7.7A Humidity Control

The humidity control is an adjustable switch that closes when the relative humidity of the air in which it is located rises to the dial set point. It opens when the RH drops 4 to 6% below the set point. If the Ultra-Aire XT150H does not run, try turning the humidity control clockwise until it reaches the stop and the knob pointer points at “Max Dry” (see back of control panel cover). If it still does not run, remove the stop screw from the panel and turn the knob farther. If it then runs, the humidity control is out of calibration or the RH is below 40%.

The Ultra-Aire XT150H is equipped with an automatic defrost mechanism. If the Ultra-Aire XT150H operates in conditions that develop frost on the evaporator, it will sense the frost build-up and automatically defrost the evaporator. The Ultra-Aire XT150H may not appear to be operating correctly during the defrost sequence, but once the defrost sequence is completed, the Ultra-Aire XT150H will resume dehumidifying.

7.7B Programmable Ventilation Timer

The ventilation timer controls the impeller fan and the motorized fresh air damper. When the ventilation timer is activated, the Ultra-Aire XT150H 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 Ultra-Aire XT150H 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 Ultra-Aire XT150H 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 4.5 of this manual.

7.8 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 impeller 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.

7.9 Electric Ventilation Damper

The electric ventilation damper is controlled by the ventilation timer. 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.

The damper opens in one direction only. The damper rotates very slowly, allow sufficient time for the damper to cycle. The damper will take approximately 1 minute to cycle from closed to open or from open to closed.

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.

7.10 Condensate Pump Kit

An optional condensate pump kit is available from the factory for use with the Ultra-Aire XT150H. Condensate is automatically pumped to a remote location when the water level in the pump's reservoir rises to close the float switch.

21 Ultra-Aire XT150H Installer’s & Owner’s Manual