M-Series Technical Manual
27
Cambridge Engineering, Inc.
IMPORTANT
Before attempting electrical installation, review the
following instructions and wiring and connection dia-
grams to make sure you have a thorough understand-
ing of what is required.
m
WARNING:
High voltage electrical input to this equipment is
required. EXTREME caution should be exercised.
This equipment must be electrically grounded in
accordance with local codes or in accordance with
National Electrical Code ANSI/NFPA No. 70.
1. Check the heater nameplate to determine the voltage
and amperage requirements.
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CAUTION:
If the supply voltage does not agree with the
nameplate voltage, notify your local agent or
Cambridge Engineering’s Customer Service Group
at 800-473-4569.
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WARNING:
For roof mounting, the gas and electrical connec-
tions must not penetrate the unit base or mounting
curb. Cambridge Engineering recommends using
pitch pockets or decktite to seal the penetrations.
2.
Wire the supply wiring and adequate Branch Circuit
Protection in accordance with the National Electric
Code ANSI/NFPA 70.
3. Mount the Remote Control Station in a location inside
of the building and convenient to the operator without
being susceptible to damage.
4. Space temperature sensors are normally located
along a perimeter wall and out of the direct path
of the discharge air or air infiltration. Consult the
design drawing or your local Cambridge Engineering
Representative for placement assistance. Do not
locate the remote mounted temperature sensors
immediately adjacent to overhead doors because the
infiltration air can affect the sensor when the door is
closed and may not adequately sense the tempera-
ture when the door is open. In dock areas, the sensor
should be located on the first column in from the
outside wall.
IMPORTANT
Observe the special notes and instructions on
the wiring diagrams including the following:
The wiring for the space temperature sen-
sors must be “shielded, twisted-pair” wiring
and must run separate from the other “AC”
wiring. This also applies to other remote
mounted controls utilized in the Maxitrol
Series 14 and 44 control systems. Shielded
wire which is routed to the electrical con-
trol enclosure on the heater should extend
beyond the high voltage section of the
enclosure before the shielding is terminated
and the wiring is distributed to its ultimate
destination. Shielding must be grounded on
one end only.
IMPORTANT
Conduit connections for power and control wir-
ing must be caulked to ensure a tight seal and
prevent moisture accumulation.
5. Wire the Remote Control Station and other tem-
perature control options using Class II wiring per
Cambridge Engineering wiring diagram and National
Electrical Code Article 725 or local codes.
6. Run conduit and primary wiring to the disconnect
switch inside of the control enclosure on the heater
per N.E.C., Article 430, ANSI/NFPA 70.
7. If applicable on vertical mount, feed the cable
marked “inlet damper” through the bottom of the
heater into the inlet damper housing. Connect wir-
ing to the damper motor junction box per the wiring
diagram.
8. Return the wiring diagram to the manual holder.
Replace and fasten all access covers.
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CAUTION:
Do not attempt to start the make-up air heater at this
time.
Premature start-up can result in damage to the
equipment and components.
INSTALLATION INSTRUCTIONS
ELECTRICAL
