Manitowoc J-1300, Service Manual

Page: 157 / 165

Section 7 Refrigeration System
7-52
11. Follow the normal evacuation procedure, except
replace the evacuation step with the following:
Important
Dry nitrogen is recommended for this procedure.
This will prevent CFC release.
A. Pull vacuum to 1000 microns. Break the
vacuum with dry nitrogen and sweep the
system. Pressurize to a minimum of 5 psi.
B. Change the vacuum pump oil.
C. Pull vacuum to 500 microns. Break the
vacuum with dry nitrogen and sweep the
system. Pressurize to a minimum of 5 psi.
D. Change the vacuum pump oil.
E. Pull vacuum to 250 microns. Run the vacuum
pump for 1/2 hour on self-contained models, 1
hour on remotes.
NOTE: You may perform a standing vacuum test to
make a preliminary leak check. You should use an
electronic leak detector after system charging to be
sure there is no leak.
12. Charge the system with the proper refrigerant to
the nameplate charge.
13. Operate the ice machine for one hour. Then,
check the pressure drop across the suction line
filter-drier.
A.
If the pressure drop is less than 1 psi, the
filter-drier should be adequate for complete
cleanup.
B. If the pressure drop exceeds 1 psi, change the
suction line filter-drier and the liquid line
drier. Repeat until the pressure drop is
acceptable.
14. Operate the ice machine for 48-72 hours. Then,
remove the suction line drier and change the
liquid line drier.
15. Follow normal evacuation procedures.
REPLACING PRESSURE CONTROLS WITHOUT
REMOVING REFRIGERANT CHARGE
This procedure reduces repair time and cost. Use it
when any of the following components require
replacement, and the refrigeration system is
operational and leak-free.
•
Fan cycle control (air-cooled only)
•
Water regulating valve
(water-cooled only)
•
High pressure cut-out control
•
High side service valve
•
Low side service valve
Important
This is a required in-warranty repair procedure.
1. Disconnect power to the ice machine.
2. Follow all manufacturer’s instructions supplied
with the pinch-off tool. Position the pinch-off tool
around the tubing as far from the pressure control
as feasible. (See the figure on next page.) Clamp
down on the tubing until the pinch-off is
complete.
WARNING
Do not unsolder a defective component. Cut it out
of the system. Do not remove the pinch-off tool
until the new component is securely in place.
3. Cut the tubing of the defective component with a
small tubing cutter.
4. Solder the replacement component in place.
Allow the solder joint to cool.
5. Remove the pinch-off tool.
6. Re-round the tubing. Position the flattened tubing
in the proper hole in the pinch off tool. Tighten
the wingnuts until the block is tight and the
tubing is rounded. (See the drawing on next
page.)
NOTE: The pressure controls will operate normally
once the tubing is re-rounded. Tubing may not re-
round 100%.