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Page 51
KN INSTALLATION AND OPERATION INSTRUCTIONS
Appendix A — suggested wiring
16
Figure A1 Indoor Air Reset wiring to IAR terminals with
3-wire zone valves and no zone controller
(see Figure 21a for terminal block
6
location)
IAR (Indoor Air Reset) wiring, when used
Wiring for 3-wire zone valves without a zone
controller
• Heat Demand terminal connections using 3-wire zone valves — The end switch
leads from the zone valves must connect to the Heat Demand LEFT SIDE (+)
terminal on the electrical connection board as shown in Figure A1.
• IAR connections — See Figure A1 for typical wiring to the IAR inputs when using
3-wire zone valves without a zone controller. For other applications, see the Con-
trol manual and Section 7 of this manual.
Polarity
— The connections to the
IAR
positive terminals (
IAR +
)
must be to the same location on the zone valve as the thermostat wire,
as shown in Figure A1. The connections to the
IAR
negative terminals
(
IAR –
) must be from the zone valve terminal connected to the 24VAC
common line, as shown. Connecting the wires incorrectly can cause the
transformer to be shorted out and damaged.
3-wire zone valves:
You will have to rewire existing 3-wire zone valves
to meet the requirements shown in Figure A1. Move the thermostat lead
and the 24VAC hot lead to the CENTER terminal of the valve. Move
the 24VAC common lead to the outer terminal of the valve. Discard
existing wires connected to the end switch terminals. Install a new wire
single wire from each end switch to the Heat Demand LEFT SIDE (+)
terminal as shown in Figure A1.
3-wire zone valves:
Always use a voltmeter to verify the wiring is
correct. The center terminal of the valve must be 24VAC to ground
when the thermostat is calling for heat. The motor common terminal
(outer post) must not have voltage. Change the wiring and retest. DO
NOT connect the wires to the boiler until you have tested as described.
Incorrect wiring can damage the boiler control or other system
components.
• If there is only one transformer feeding all of the zone valves in the system, you can
omit the wires to the
IAR
negative terminals (
IAR –
) on all but one of the zone
valves. This is because these terminals are jumpered internally on the electrical
connection board. If there is more than one transformer, provide one wire from
each transformer common side to one of the
IAR
negative terminals (
IAR –
).