Adjust. - TM-5-4120-339-140105

TM 5-4120-339-14

(1) Refer to figure 4-12 and tape the bulb of a thermometer to the suction line near the power bulb of the

quench valve.

(2) Refer to figure 3-4 and install the evaporator fan.

(3) Refer to figure 3-13 and install the junction box.

(4) Refer to figure 4-5 and install a suction pressure gage.

(5) Connect the air conditioner to the electrical power source.

(6) Turn the selector switch to the "COOL" position and turn the thermostat control knob counter-clockwise to

its limit. Operate the unit on cool for approximately 30 minutes to stabilize thermometer reading.

(7) At the end of 30 minutes operation, note the pressure indicated on the suction pressure gage. To this

add 2 psig (estimated suction line loss).

(8) Refer to table 4-2 and convert pressure (gage pressure plus 2 psig) to temperature.

(9) To calculate the superheat of the quench valve, deduct the temperature calculated in step (8) from the

temperature indicated on the thermometer attached to the suction line. The superheat of the quench valve should be

30.4F .5F (-0.88C 0.5C).

(10) If the superheat is as specified in step (9),.no adjustment is necessary.

(11) If the superheat is not as specified in step (9), adjust the quench valve as follows:

(a) Remove the seal cap on the side of the quench valve.

(b) The quench valve superheat is adjusted by turning the adjusting screw. Turning the adjusting screw

counter-clockwise increases flow and lowers superheat. Turning the adjusting screw clockwise decreases flow and raises

superheat. Four completes turns will raise or lower the superheat by approximately 2 F (1.1C). Turn the adjusting

screw to obtain the superheat specified in step (9).

(d) Calculate superheat of the quench valve. If superheat is now as specified in step (9), no further

adjustment is necessary. If superheat is not as specified, continue the adjustment cycle until the superheat reaches the

specified temperature allowing at least 20 minutes running time between adjustments.

(e) When adjustment is completed, turn the selector switch to the "OFF" position and disconnect the air

conditioner from the electrical power source.

(f) Refer to figure 3-13 and partially remove the junction box.

(g) Refer to figure 3-4 and remove the evaporator fan.

(h) Refer to figure 4-12 and remove the thermometer bulb from the "OFF" position and disconnect the air

conditioner from the electrical power source.

(i) Install the seal cap on the quench valve.

(j) Refer to figure 3-4 and install the evaporator fan.

(k) Refer to figure 3-13 and install the junction box.

(l) Refer to figure 4-5 and remove the suction pressure gage.

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