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KFFEH: Installation Instructions
For 3 kW through 10 kW non-fused or non-circuit
breaker models:
Refer to unit Installation Instructions for recommended wiring
procedures.
Install wiring in accordance with all applicable local and national codes
(see
Table 2
and
Table
3).
3 kW through 10 kW non-fused or non-circuit breaker models have high
voltage terminal block to connect the high voltage field wiring as shown
in
Fig.
6.
Fig. 6 – 3kW through 10kW High Voltage Terminal Block for High
voltage field Wiring
1. Connect heater wiring harness plug to receptacle on PCB or wire
harness. A positive connection must be made between plug and
receptacle. Plug will interlock with receptacle when properly
seated. Harness contains both 24V control and high voltage wiring.
Blower power is provided through heater harness.
2. Heater Staging
If electric heat staging is required, a multi-stage heating room
thermostat is required. Consult your equipment supplier for a
suitable thermostat.
a. The 3-, 5-, 8-, and 10-kW heaters are single stage only.
b. The 9- and 15-kW heaters are adaptable for 2-stage operation.
c. The 18-, 20-, 24-, and 30-kW heaters are adaptable for 3-stage
operation.
3. Rectifier and Time Delay Boards
Each heater element is controlled by a relay mounted on the heater
panel. The relay has a 24V DC coil. Each relay has a small rectifier
board attached directly to relay coil terminals. The rectifier board
converts incoming 24V AC control signal to DC. Some heaters may
have up to three relays. The second and/or third relay rectifier board
also has a time delay feature and a small jumper wire built into it.
With the jumper uncut, the time delay allows the second-stage heat
to be energized approximately 5 seconds after the first stage. On
18-, 24-, and 30-kW heaters, the third-stage relay board jumper is
cut at the factory. This provides an 8-second delay after first-stage
relay closes.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
A221146
4
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