Carrier 50DL - Manual (Page 8)

4. If the unit is equipped with electric heat, the room
terminals must be controlled to go fully open
when unit goes into heating. An interlock relay is
provided in the variable volume box. When unit
goes into heating, the interlock relay energizes
providing switch closure to open the room ter­
minals. Field connections for the interlock relay
are terminals 1 and 2 of the terminal block (TB10)
located in upper left corner of electric heat sec­
tion (Fig. 11).
Route field-supplied power wiring thru watertight
connector supplied in unit cornerpost. Make TBIO
connections as shown in Fig. 13.
Return Air Filters — Check that return air filters
are of the correct type and size and installed in unit
filter racks. Filter data is shown in Table 1. Do not
operate unit without return air filters.
Fig. 13 — Morning Warmup Interlock
Outdoor Air Inlet Screens — Outdoor air inlet
screens must be in place before operating unit.
Compressor(s) — Loosen compressor holddown
bolts until sidewise movement of the washer under
each holddown bolt head occurs. Do not loosen
completely as bolts are self-locking and will main­
tain their adjustment.
Open the compressor discharge and suction
service valves. Replace and tighten valve caps to
prevent leaks.
Liquid Line Service Valve — Open the liquid line
service valve. Replace and tighten valve cap to
prevent leaks.
Low Ambient Compressor Lockout (Fig. 14) —
All units are equipped with an adjustable low
ambient lockout thermostat to lock off the com-
pressor(s) at low outdoor air ambients. Thermostat
is located in the main control box. Setting will
depend on specific installation but should be
approximately 50 F on VAV units and 55 F on
constant volume units.
Convenience Outlet — All units are equipped
with a 115-volt convenience outlet for handling
small power load or service light. See Fig. 14.
CIRCUIT BREAKERS CONVENIENCE OUTLET LOW AMBIENT LOCKOUT
THERMOSTAT
LOGIC PANEL
Fig. 14 — Control Box