TABLE 5: Heat Relays |
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Input | Heat Relay Output |
W1 | HT1 |
W2 | HT1 and HT2 |
W1 and W2 | HT1 and HT2 and HT3 |
The control energizes the first stage of electric heat immediately, the second stage 10 seconds after the call for second stage heat, and the third stage 20 seconds after the call for third stage heat.
Depending on the heat kit installed in the air handler, the control pro- vides the flexibility to configure the amount of heat delivered with the first stage heating call. As an example, when the control’s W1 input is connected to the room thermostat’s first stage heat signal, a call for first stage heat will energize one heating element (HT1). If the control’s W2 input is connected to the room thermostat’s first stage heat signal, a call for first stage heat will energize two heating elements (HT1 and HT2). With either configuration, the control will energize three heating ele- ments (HT1, HT2, and HT3) when it receives a first and second stage heat input from the thermostat.
Limit Switch and Lockout Operation
Limit Switch Operation
If the HEAT ENABLE jumper is in the HEAT position and the limit switch opens (fault code 1), the control will immediately
Fan On Lock Condition
If the limit switch opens multiple times during a single call for electric heat (fault code 3) or if the limit switch opens for a long duration (fault code 4), the control will energize the blower until power is removed from the control. The control will cycle the heat outputs on and off as the limit
Soft Lockout
If the limit switch opens for a second long duration period during a sin- gle call for heat (fault code 5), the control will keep the blower locked on and lock out the heat outputs for one hour. The control will only reset this one hour lockout when the power is removed from the control. After the one hour period has passed, the control will
Hard Lockout
The control has a hard lockout condition during which the control will keep all heat outputs
If the limit switch closes and
If the limit switch opens twice when no call for electric heat is present (fault code 2), the control will enter a hard lockout condition.
If the limit switch opens multiple times soon after a soft lockout reset (fault code 6), the control will enter a hard lockout condition.
Wiring Related Faults
If the control receives a simultaneous call for heating and cooling (fault code 7), the control will perform both heating and cooling operations.
SECTION VII: LINE POWER
CONNECTIONS
Power may be brought into the unit through the supply air end of the unit (top when unit is vertical) or the left side panel. Use the hole appro- priate to the unit’s orientation in each installation to bring conduit from the disconnect. The power lead conduit should be terminated at the electrical control box. Refer to Tables 11, 12, 14 and 15 to determine proper wire sizing. To minimize air leakage, seal the wiring entry point at the outside of the unit.
All electrical connections to air handlers must be made with copper con- ductors. Direct connection of aluminum wiring to air handlers is not approved.
If aluminum conductors are present, all applicable local and national codes must be followed when converting from aluminum to copper con- ductors prior to connection to the air handler.
If wire other than uncoated
Additionally, existing aluminum wire within the structure must be sized correctly for the application according to National Electric Code and local codes. Caution must be used when sizing aluminum rather than copper conductors, as aluminum conductors are rated for less current than copper conductors of the same size.
TYPICAL WIRING WITHOUT ELECTRIC HEAT
GND. LUG |
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POWER
SUPPLY
1 PHASE ELECTRIC HEAT
WITH CIRCUIT BREAKER
& BREAKER BAR REMOVED
GND. LUG | GND. |
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POWER |
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SUPPLY 1 |
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POWER |
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SUPPLY 2 |
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POWER |
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SUPPLY 3 |
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MAY BE 1, 2, OR 3 |
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CIRCUIT BREAKERS |
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ELECTRIC HEAT
WITHOUT CIRCUIT BREAKER
3 PHASE (10 - 15 KW)
GND. LUG | GND. |
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POWER |
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SUPPLY | TERMINAL |
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ELECTRIC HEAT |
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WITHOUT CIRCUIT BREAKER
SINGLE SOURCE (2.5 - 10 KW)
GND. LUG | GND. |
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POWER |
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SUPPLY |
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CONNECT TRANSFORMER LEADS WITH WIRE NUTS (TYPICAL ALL HEAT KITS)
1 PHASE ELECTRIC HEAT WITH CIRCUIT BREAKER AS SHIPPED FROM FACTORY SINGLE SOURCE
(2.5 - 25 KW) - 25 KW SHOWN
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POWER
SUPPLY
(JUMPER BAR)
MAY BE 1, 2, OR 3
CIRCUIT BREAKERS
POWER WIRING
FIGURE 15: Line Power Connections
Johnson Controls Unitary Products | 11 |