Roth AHTR Series, Installation & Operation Manual, Page: 5 / 14

AHTR Series Elec Heat IOM, August 2010
5
AHTR Series Elec Heat IOM, August 2010
Roth
Section 4: Installation
LOW VOLTAGE WIRING
6. Connect the 6-Pin heater wiring harness to
the receptacle located inside the cabinet
(Top Cover). A perfect match and positive
connection must be made between the
plug and receptacle. The plug will interlock
with receptacle when properly seated.
Harness contains 24 Volts wiring.
WIRING
7. Route unit power supply through knockout
in top of unit and connect to line side of
disconnect. Connect ground wire to ground
lug. See wiring diagram label to make
connections. All line voltage connections
and ground connections MUST be made
with copper wire.
The power supply wiring MUST have
overcurrent protection. This can be either
fuses or circuit breakers. The maximum size
for the overcurrent protection is shown in the
column labeled “Max. Fuse or NEC HACR
Breaker (Amps)” in the electrical Data Table
or on the unit rating plate. Connect supply
voltage wires to the Circuit Breakers on the
heater or to the terminal block on the heater.
NOTE: Supply voltage, amperage, fuse and
disconnect switch sizes MUST conform with all
technical specifications in this manual and on
the unit rating plate.
GROUNDING
8. Permanently ground the electric heat
accessory in accordance with local codes
and ordinances and in the United States
with National Electrical Code ANSI/NFPA70-
2008 or current edition. Use a copper
conductor of the appropriate size from the
electric heat accessory ground lug, to a
grounding lug on the circuit breaker panel.
On models with more than one circuit, a
separate copper ground wire MUST be
connected for each circuit.
8. Install top front door panel.
9. Mark an “X” in the appropriate box for the
heater on the unit rating plate.
TIME DELAy MODULE
10. The time delay module stages the heater
elements for 15kW and 20kW heaters. In
most cases, all of the DIP switches should
be in the “ON” position, which will provide
a 1,023 second (approximately 17 minute)
delay between the first and second stage
of electric heat.
For example, if all of the switches are
in the “ON” position of a 20kW heater,
only 10kW will be energized when the
thermostat calls for backup or emergency
heat. After approximately 17 minutes of
continuous demand from the thermostat,
the second bank of electric heat will
be energized, providing the full 20kW of
heat. The DIP switches may be set in any
manner that is desired.
There are 10 DIP switches that are
cumulative. In other words, starting with
the first switch, the time delay for each
additional switch that is in the “ON”
position is added to the previous switch.
The switches are labeled 1, 2, 4, 8, 16,
32, 64, 128, 256, and 512. When all of
the switches are in the “ON” position,
all of the numbers must be added to
determine the time delay. In the case
of all switches in the “ON” position, the
delay is 1+2+4+8+16+32+64+128+256+512
= 1,023 seconds. If only 8 to 9 minutes
is desired between stages, place all
⚠
WARNING
⚠
ELECTRICAL SHOCK HAZARD
THE UNIT CAbINET MUST HAVE AN
UNINTERRUPTED OR UNbROKEN
GROUND TO MINIMIZE PERSONAL
INjURy IF AN ELECTRICAL FAULT
SHOULD OCCUR. THE GROUND MAy
CONSIST OF ELECTRICAL WIRE OR
METAL CONDUIT WHEN INSTALLED WITH
EXISTING ELECTRICAL CODES.