10
MOUNTING
Mounting brackets with 7/16” dia holes are provided
for flush mounting to the ceiling. For details refer to
dimensional data on page 6. Ensure adequate clear-
ance (at least 24”) is provided behind the coil as well
as each side (to enable access to the electrical and
refrig. compartments).
Ensure that the ceiling is level since the drain pan
has been sloped for drainage during the defrost
cycle.
DRAIN LINE
The drain line should be run from the drain connec-
tion, sloping at least 4” per foot. A trap outside the
room will prevent warm air from entering through the
tubing. Connection should be made to proper drainage
facilities that comply with local regulations.
To prevent freeze-up when the temperature of the
refrigerated space is 32
o
F or lower, the drain line
should be heated along its run inside the cold room.
The heated drain line should be insulated. It is recom-
mended that the heater be energized at all times. A
heat input of 20 watts per foot in a 0
o
F room and 30
watts per foot in a -20
o
F room is usually satisfactory.
The drain pan may be mounted with the drain fitting at
either end (remove pan heater and relocate pan). See
page 6 for drain fitting details.
Ensure that the drain pan has sufficient slope for
proper drainage (prevention of ice build up/block-
age in pan).
PIPING
Refrigerant line sizes are important and may not be
the same size as the coil connections. (depends on
the length of run) If in doubt, consult “Recommended
refrigerant line sizes” charts. (Engineering Manuals or
other recognized sources of information).
WIRING
Wire system in accordance with governing standards
and local codes. See data and wiring diagrams on
pages 2, 3, 4 and 5 for wiring arrangement. Electrical
wiring is to be sized in accordance with minimum
circuit ampacity rating.
For ease of identifying the proper wiring terminals, unit
wiring is colour coded and terminal block connections
are identified. When fan delay thermostats (combi-
nation fan delay and defrost termination) are installed,
on start-up, the fans do not operate until the coil
temperature is reduced to approximately
20
o
F. It is normal for the fans to cycle a few times
until the room temperature is brought down. At higher
evaporating temperatures this control may not close
and therefore should be by-passed or replaced with an
adjustable type.
The defrost termination control is adjustable and
may be set at a minimumof 40
o
F (fully CW) to a
maximum of 75
o
F (fully CCW). Normal setting is
55
o
F. This can be increased if the defrost heat-
ers are terminated too soon (frost still left) or
decreased if terminated too long (steaming of
coil). Time clock should be set for a fail-safe time
termination of 30 minutes.
SYSTEM CHECK
Before Start-Up:
1. All wiring should be in accordance with local
codes.
2. Refrigerant lines should be properly sized.
3. Electric defrost systems should include a
liquid line solenoid valve.
4. Thorough evacuation and, dehydration has
been performed.
5. The suction, discharge, and receiver service
valves must be open.
6. The system should include a liquid line drier
mois ture indicator and suction filter.
7. Pour enough water into the drain pan to allow
a good check on drainage and seal the trap.
After Start-Up:
1. If necessary, temporarily by-pass fan delay
control to run fans until room temp is lowered.
(Run jumper wire from terminal N to F on
control circuit terminal block).
2. Check the compressor oil level to ensure the
correct oil charge.
3. Be sure that the expansion valve is properly
set to provide the correct amount of superheat.
(should be around 5 to 6
o
F for 10
o
F T.D.
operation).
4. Heavy moisture loads are usually encountered
when starting the system for the first time. If
the coil temperature is below freezing, this will
cause a rapid build-up of frost on the coil.
During the initial pull-down frost build-up
should be watched and the coil defrosted
manually, as required.
5. Check for proper evaporator fan blade rotation.
MAINTENANCE
The unit should be periodically inspected for any
dirt or build-up on the fin surface and cleaned if
necessary with a soft whisk or brush.
Also ensure coil and pan does not have any
excessive ice build-up from improper defrost
operation. When replacing heater elements first
remove heater slot covers and heater clips. (See
page 9 for detailed view).
