Service Manual

SERVICING
31
WARNING
DISCONNECT ELECTRICAL POWER SUPPLY.
1. Remove the w iring from the control terminals.
2. Using an ohmmet er test for continuity across the normally
closed contact s. No reading indicat es the control is open -
replace if necessary. M ake sure t he limit s are cool before t est-
ing.
IF FOUND OPEN - REPLACE - DO NOT WIRE AROUND.
S-52 CHECKING HEATER ELEM ENTS
Optional electric heaters may be added, in the quantit ies shown
in the spec sheet for each model unit, t o provide electric resis-
tance heating. Under no condition shall more heaters than the
quantit y shown be inst alled.
WARNING
1. Disassemble and remove the heat ing element(s).
2. Visually inspect the heater assembly for any breaks in t he
wire or broken insulators.
3. Using an ohmmet er, test the element for continuity - no read-
ing indicates the element is open. Replace as necessary.
S-100 REFRIGERATION REPAIR PRACTICE
DANGER
ALWAYS REMOVE THE REFRIGERANT CHARGE IN
A PROPER MANNER BEFORE APPLYING HEAT TO
THE SYSTEM.
These models use t he FasTest Access Fitting Syst em, with a saddle
that is eit her soldered t o the suction and liquid lines or is fas-
tened with a locking nut to the access fitt ing box (core) and then
screwed int o the saddle. Do not remove the core from the
saddle until the refrigerant charge has been removed. Failure
to do so could result in property damage or personal injury.
When inst alling a new core or reinst alling the core after removal,
it is very important to note t hat before inserting the core into
the saddle, the core and saddle must be free of debris and the “ O”
Ring must have a thin coat ing of refrigerant oil applied to it. The
oil is to prevent the “ O” Ring from being deformed w hen t he core is
tightened complet ely. The core should be torqued to 8 ft . lb.
When repairing the refrigerat ion syst em:
WARNING
DISCONNECT ELECTRICAL POWER SUPPLY.
1. Never open a syst em that is under vacuum. Air and moist ure
will be drawn in.
2. Plug or cap all openings.
3. Remove all burrs and clean t he brazing surfaces of the tubing
wit h sand cloth or paper. Brazing materials do not flow well
on oxidized or oily surfaces.
4. Clean t he inside of all new tubing t o remove oils and pipe
chips.
5. When brazing, sw eep the tubing with dry nit rogen to pre-
vent the format ion of oxides on the inside surfaces.
6. Complete any repair by replacing the liquid line drier in t he
system, evacuat e and charge.
At any time t he syst em has been open for repair, the fact ory
inst alled liquid line filter drier
must be replaced.
BRAZING M ATERIALS
Copper to Copper Joints - Sil-Fos used without flux (alloy of 15%
silver, 80% copper, and 5% phosphorous). Recommended heat
1400°F.
Copper to Steel Joints - Silver Solder used w ithout a flux (alloy of
30% silver, 38% copper, 32% zinc). Recommended heat - 1200°F.
Aluminum to Aluminum and Copper to Aluminum Joints - ZA-1
Brazing Rods use Flux Syst em Cesium-Based Polymer Syst em (al-
loy of 78% Zinc and 22% Aluminum); M elt ing point 826°F - Flow
point 905°F.