Test or Inspection
Test or Inspection
(6) Secure the adjusting screw in this
13.Refrigeration Compressor Knocking
position with the setscrew (11).
. Check for lack
in the crankcase.
Add oil (fig. 3-1).
Step 2. Check for oil or liquid refrigerant in the piston
If the clutch shows a tendency to slip when load is applied,
tighten adjusting nut as above until there is no slippage.
b. Belts Adjustment All belts are adjusted to a
Add oil compressor (fig. 3-1).
14.Carbon Dioxide Cylinder Filling Unit Capacity Low
tension permitting 1-1/2 inch (3.81cm) deflection
Step 1. Check for obstruction in valves or loose nuts and
under firm thumb pressure midway between
pulleys, except the transfer pump belt, for which
crossed or worn valve threads.
1 inch (2.54cm) deflection is specified. All belts
Remove and clean or replace the defective
are tensioned by loosening the connected unit on
its base, moving it as required, and tightening
Step 2. Test the pressure regulating valve charging pressure
the base fasteners to hold the tension.
by slowly operating valve and checking the pressure
Step 2. Check the sight glass to see if refrigeration system is
gage (fig. 4-17).
Slowly adjust the pressure
low on freon.
regulating valve 14 (fig. 4-18), until a charging
Recharge system as follows:
pressure of 600 to 800 psi (42.18 to 66.24 kg per sq
a. Install a discharge pressure gage In the
discharge service valve.
cool weather; 800 to 1,000 psi (56.24 to 70.30 kg per
b. Connect a full freon cylinder to the gage port
sq cm) is suitable in hot weather.
Step 3 Check for slipping clutch belts.
Adjust belts to a tension permitting 1-1/2 inch
Before tightening the charging hose
(3.81cm) deflection under firm' thumb pressure
connection at the compressor, crack the cylinder
midway between pulleys. All belts are tensioned
valve slightly to purge air from the hose.
by loosening the connected unit on its base,
d Close the suction service valve (2) one turn.
moving it Ls required, and tightening the base
fasteners to hold the tension.
from the supply cylinder until the sight glass
Step 4. Check for a clogged strainer.
appears full of refrigerant.
Dry cleaning solvent, P-D-680 or P-S661, used to
If the compressor pounds, or frost forms on the cylinder
clean parts is potentially dangerous to
head, throttle down the rate of the flow of refrigerant with
personnel and property. Use in a well-ventilated
the freon cylinder valve.
area as the fumes are dangerous if inhaled.
Avoid repeated and prolonged skin contact. Do
11 Pressure Vessel Low, Refrigeration Unit Operates On
not use near open flame or excessive heat.
Flash point of solvent is 100F.-138F. (38C.-
Check for tank alarm pressure switch being out of
adjustment (The correct setting is 305 on the high
side (knob 5) and 295 on the low side (knob 6).
Wash all parts in a cleaning solvent, Fed.
Readjust the tank alarm pressure switch as
Spec P-D-680 or P-S-661. Clean the gasket
mating surfaces thoroughly.
Adjust the tank pressure switches (4, fig.
4-15) by turning the adjusting
15. Cylinder Filling Unit Compressor Knocking
knobs (5 and 6) to the desired setting on
Step 1. Check for a loose pulley by applying hand pressure
the scale. Set the pressure switch (8),
back and forth.
connected to the conversion heater at
Tighten the pulley bolts.
275 on the high side and 260 on the low
Step 2. Check for empty cylinder.
12.Pressure Vessel Pressure Too Low, Refrigeration Unit
16. Liquid Level Gage Reads Low Or High
Step 1. Check for no liquid carbon dioxide in the storage
Step 1. Check the liquid level gage shutoff valve for leaks
Fill the storage tank.
Tighten the packing glands with valves
Step 2. Check for the tank being recently filled with relatively
partially open until the leakage stops.
cold carbon dioxide.
Wait for newly installed carbon dioxide to