RH-D AND RH-W ELECTRIC DUCT HEATERS
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INSTALLATION, OPERATION AND MAINTENANCE MANUAL
RENEWAIRE.COM
INSTALLATION
WARNING
ARC FLASH AND ELECTRIC SHOCK HAZARD
All models of Electric Heaters as discussed in this manual operate on high voltages that can cause
severe electric shock. Some models of Electric Heaters use high voltages that are capable of
causing dangerous arc flash. Whenever accessing any part or component of the heater, disconnect
all electric power supplies, verify with a voltmeter that electric power is OFF and wear protective
equipment per NFPA 70E when working within the electric enclosure. Failure to comply can cause
serious injury or death.
The terminal blocks contain live high-voltage.
The only way to ensure that there is NO voltage inside the unit is to install and open a remote
disconnect switch and verify that power is off with a voltmeter. Refer to unit electrical schematic.
Follow all local codes.
RISK OF ELECTRIC SHOCK OR EQUIPMENT DAMAGE
Whenever electrical wiring is connected, disconnected or changed, the power supply to the electric
heater and its controls must be disconnected. Lock and tag the disconnect switch or circuit breaker
to prevent accidental reconnection of electric power.
CAUTION CAUTION
5.8 CONNECT ELECTRIC SERVICE
5.7 VERIFY AIRFLOW DIRECTION (RH-D UNITS ONLY)
5.9 CONNECT THERMOSTAT (RH-W ONLY)
High voltage electric service is to be brought into the unit through one of the factory-provided knockouts
located on the side of the control box. Wiring is to be terminated on the terminal block and grounding
lug as shown in the photo in Section 5.9.1 of this manual. Also see the wiring schematics in Section
8.0 of this manual. Observe all local codes.
RH-W heaters require an external 0 - 10 VDC signal to control the heater output. This is normally
accomplished by using a CTH291 wall thermostat, which also requires 24 VAC to operate. The low
voltage thermostat wiring should enter the heater through the second knockout located on the side
of the control box. Wiring is to be terminated as shown in the wiring schematics in Section 6.0 of this
manual.
5.6 DUCTWORK INSULATION
The Supply Air ductwork leading from the output side of the heater to the Occupied Space should be
insulated to prevent heat loss. Individual jobsite conditions will dictate whether the duct leading to the
inlet side of the heater should also be insulated. In some cases, the air being supplied to the heater
is coming from an Energy Recovery Ventilator (ERV) and the connecting duct passes through a space
that is not conditioned. In this case, the ductwork from the ERV to the heater should also be insulated.
5.8.1 Line Voltage Wiring Entry Point
The Outlet Air Temperature Sensor must be positioned on the outlet side of the heater. Check the airflow
direction through the heater. If necessary, move the sensor to the outlet side, as shown in Section 2.1
of this manual.
