Refrigeration System - Scotsman NM952R Service Manual

REMOVAL AND REPLACEMENT: Refrigeration System
General:
Scotsman recommends that any work on the
refrigeration system only be done when it is
certain that the system needs repair.
The access valves are at the front of the
cabinet. To use them, remove the cap from the
valve ports and the cap from the top of the
valve body. Attach gauge manifold and then
use a 3/16" allen wrench to loosen the valve.
Although pressure readings may be taken with
the valve cracked open, several turns are
required to completely open the valve. Close
valve and replace caps when the job is
finished.
ALLEN WRENCH
Torque Stem to
6-8 ft. lbs.
Refrigerant should not be added except as a
way to determine the proper operation of the
product. If the system was low on refrigerant,
there is a leak, and it must be found and
repaired.
Although this system uses R-22, it must not
be vented to the atmosphere.
This system has a critical charge, it must be
recharged with the correct amount of
refrigerant as listed on the nameplate of the
ice machine, or performance will suffer.
Anytime the refrigeration system has been
opened, the dryer should be replaced.
When brazing the tubing connections to the
thermostatic expansion valve, the component
must be protected by heat sink material.
Torque Cap to
8-12 ft. lbs.
ACCESS
VALVE
Torque Cap to
7-12 ft. lbs.
November 1992
Page 33
Specifically:
Recover, reclaim or recycle refrigerant. Although
the method chosen is up to the service
company, Scotsman recommends reclaim.
There are various mechanical devices that may
be used to recycle refrigerant at the field level,
however, Scotsman requires that any refrigerant
placed into a Scotsman ice machine meet ARI
spec 700-88. Reclaim programs are available
thru most refrigerant wholesalers.
Use conservation minded service procedures:
Refrain from checking refrigeration pressures
without reason. There are many ways to
determine the proper operation of a
Scotsman ice machine without using
refrigerant gauges. Visual inspection of the
water system, amp draw, voltage, and other
techniques will lead to proper diagnosis.
If gauges must be used, do not always check
the high side pressure. If the condenser is
clean and seems to be operating correctly, it
most likely is. The low side pressure is much
more important on an ice machine than is the
high side.
If gauges must be used, use very short
hoses. Minimal refrigerant discharged into the
hoses equals minimal refrigerant discharged
into the air.
If using recycled refrigerant, it must meet ARI
spec 700-88 or have been cleaned by a
machine capable of attaining ARI spec 700.
NM952R