Product manual

25
ComPac 6/09-18
4. For units designed for operation on 208/230v, 60Hz power supply, the transformer is factory wired
for a 230v power supply. For a 208v power supply, remove the orange lead from the transformer
and connect the red lead. Insulate the orange lead.
Dual Unit Phasing
For applications where one controller operates two units, e.g., the CommStat 3 or LL357D.
The LL357D4 and the LL357D3 do not require unit phasing. However, if other devices are connected
to the control system, phasing of the air conditioner is required. Earlier models; i.e., LL357, LL357A,
LL357D2 require the unit to be properly phased.
1. Wire each unit as described in steps 1 through 4 above.
2. Test for proper phasing as follows:
A. Power up the units.
B. Using an AC volt meter set to the 300 volt scale, measure voltage between terminal L1 on the
compressor contactor of unit #1 and terminal L1 on the compressor contactor of unit #2 If
voltage is present, units are wired out of phase and must be rewired.
C. If units are not in phase, turn off power and reverse the eld power leads connected to the
internal circuit breaker on one of the units only.
D. Restore power and retest the phase (step B). When the voltage reads "0", the units are in
phase.
E. Turn off power and proceed.
Low Voltage Wiring
1. On single units, pull the low voltage wiring (e.g., 18 gauge 4-conductor Class 2 thermostat wire)
from the ComPac
®
A/C into the thermostat / subbase assembly. See Figure 8d for connections to
various thermostats.
2. Mount the thermostat on the wall of the shelter. The thermostat should be located so that the sup-
ply air from the unit does NOT blow directly on to the thermostat. Connect the thermostat to the
terminal block in the ComPac air conditioner as shown in Figures 8a and 8b.
3. On dual units, refer to the Marvair
®
LL357D4 Lead/Lag Controller Specication Sheet or Com-
mStat 3™ Controller Specication sheet. Level and install the LL357D4 or CommStat 3 subbase.
Wire the two ComPac
®
units to the Lead/Lag Controller, according to the wiring diagram on the
specication sheet and as shown in Figure 8c or 8d (note: the diagram also appears on the back
cover of the controller).
Remote Signalling: Terminals 5 & 7(N.O.) and 6 & 7 (N.C.) on the ComPac
®
A/C terminal board are
dry contacts which can be used for remote signalling in the event of a/c cutoff on low or high pressure
limit.
Continuous fan operation: For continuous indoor fan operation on single units, install a jumper between
terminals 8 and 3. For continuous indoor fan operation on dual units using the LL357D4, install jumper
between 8 and 3 and remove jumper between 1 and 3.
CommStat 3™ Controller (See Figure 8c)
The CommStat 3™ Controller by Marvair
®
is a solid state control package designed to operate a
fully or partially redundant air conditioning system for a telecommunication cabinet or shelter. The
CommStat 3 Controller is factory programmed with standard industry set points to facilitate installa-
tion. If desired, each of the set points can be quickly and easily changed in the eld by the installer.