4. Slowly open the low pressure service valve. Operate the unit for 30 minutes to
allow the system and the thermometer to stabilize.
5. Observe the low pressure (suction) gauge. Record the gauge reading and add
2 psig for estimated line loss.
6. Refer to Table 5-9 and convert pressure recorded in Step 6 (including 2 psig
additional for line loss) to temperature.
7. Observe and record the temperature indicated on the thermometer. Deduct the
temperature calculated in Step 7 from this reading to obtain superheat. Superheat of the
expansion valve should be 6 F +/ 1/2 F hotter than the temperature calculated in Table 5-9.
The expansion valve should be replaced if superheat is not specified.
8. If the superheat is within the specified limits:
(a) Disconnect the power supply.
Slowly close the low pressure service valve.
(d) Remove the low pressure hose from the service valve after first slowly
releasing the hose pressure.
c. R E M O V A L .
Use great care to avoid contact with liquid refrigerant or refrigerant
gas being discharged from any container under pressure. Sudden
and irreversible tissue damage can result from freezing. Wear
thermal protective gloves and a face protector or safety glasses in
any situation where skin or eye contact is possible.
Prevent contact of refrigerant gas with flame or hot metal surfaces.
Heat causes the refrigerant to break down and form carbonyl
chloride (phosgene), a highly toxic and corrosive gas. In case of
refrigerant leaks, ventilate area immediately.
5. Visually inspect expansion valve (4) for damage. Check for evidence of leakage.
1. Remove mastic from sensing bulb.
2. Remove sensing bulb and line from clamped position.
3. Remove two bolts (1), spacers (3), and lockwashers (2) from valve (4).