Low voltage interface connector, Adding a remote wall thermostat, Connecting a remote wall thermostat – Friedrich KUHL R-410A User Manual

Page 33: Warning

ELECTRIC SHOCK HAZARD

WARNING

Disconnect power to the unit before

servicing. Failure to follow this warning

could result in serious injury or death.

Low Voltage Interface Connector

All Kuhl and Kuhl + units have a low voltage interface connector through
which a Remote Wall Thermostat, Desk Control and Auxiliary Fan’s Relay
can be connected. The interface connector is located on the left side behind
the decorative front cover.

Interface Connector Definitions

Interface Connector Location

Table 1

Front Panel. Wire jumper between FP and

F2 enables front panel operation. Jumper off

enables remote wall t-stat operation.

Used with F1 to provide 24 VAC to external

fan relay. (See above for use with FP)

Used with F2 to provide 24 VAC to

external fan relay.

Used with D1 for desk control on or off

operation.

Used with D2 for desk control on or off

operation.

Common Ground Terminal

Call for high fan

Call for low fan

Call for compressor

Call for heating

24V Power from Electronic Control to Wall

Call for heat pump reversing valve

Figure 1

Adding a Remote Wall Thermostat

An external thermostat may be added to the air conditioner to provide
remote temperature sensing and control.

Thermostat Selection

Friedrich recommends the use of either the Friedrich RT4 or RT5. These
thermostats are single stage heat/cool, manual changeover. The RT4 is a
digital display thermostat with single speed fan control. The RT5 features
a digital display, two fan speed selection, fi lter check light, temperature
limiting, status indicator light, room temperature offset, backlight and
battery backup. Other thermostats may be used as long as they are single
stage heat/cool and are confi gured correctly for the unit.

Thermostat terminals requirements

For cooling only units: C, R, G, Y.
For cooling with electric heat units: C, R, G, Y, W.
For heat pump units: C, R, G, Y, W, B.

For two fan speeds, thermostat must have 2 fan speed selection.

During Heat Pump Mode:

The B terminal must be continuously energized. The W terminal must have
24 VAC output to call for heat. The control board decides on whether to
turn on the Heat Pump Heat (compressor) or Electric Heat. The Y terminal
should not have 24 VAC output during heat mode.

To enable the remote thermostat operation, remove the jumper between
terminals FP & F2 on the interface connector. Connect the thermostat
using Figure 1 and Table 1 as a guide.

Procedure

1) Unplug the unit.

2) Unscrew and remove the decorative front cover. (Page 30)

3) Locate the Interface Connector (24 VAC terminal strip (See fi gure 1 at
left) and remove the jumper wire at FP and F2.

4) Make the wire connections according to the confi guration needed for
your unit (see above or page 68 for wiring diagrams).

5) Once each wire is matched and connected, the unit is now ready to be
controlled by the thermostat.

6) Reattach the decorative front cover (see page 30).

Note: Under T-Stat operation the front panel is disabled

except the Maintenance functions (see page 29 for details).

Connecting a Remote Wall

Thermostat