Friedrich Complete Thermostat Manual for Efficient Control of Air Conditioner Units

Low Voltage Interface Connections

All Vert-I-Pak 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 electronic control board.

Figure 1 Interface Connector Location

Questions concerning proper connections to the unit should be dirrected to the factory.

Table 1

	Interface Connector Definitions
FP	Factory use only.
	(Ensure there is no jumper at FP an F2)
F2	Used with F1 to provide 24 VAC to external
	fan relay. (Ensure there is no jumper at FP an F2)
F1	Used with F2 to provide 24 VAC to
	external fan relay.
D2	Used with D1 for desk control on or off
	operation.
D1	Used with D2 for desk control on or off
	operation.

CCommon Ground Terminal

GH	Call for high fan
GL	Call for low fan

BCall for heat pump reversing valve Y Call for compressor

W Call for heating

R 24V Power from Electronic Control to Wall

Remote Wall Thermostat

All Friedrich Vert-I-Pak units are factory configured to be controlled by using a single stage heat/cool remote wired wall mounted thermostat.

Thermostat Selection

Friedrich recommends the use of the Friedrich RT4 and RT6. These thermostats are single stage heat/cool, manual changeover. The RT4 is a digital display thermostat with single speed fan control. The RT6 features a digital display, two fan speed selection, temperature limiting, status indicator light, room temperature offset, and backlight. Other thermostats may be used as long as they are single stage heat/cool and are configured correctly for the unit.

Thermostat terminals requirements:.

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.

HEAT PUMP UNITS

During Heat 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.

Connecting a Remote Wall Thermostat

WARNING

ELECTRIC SHOCK HAZARD

Disconnect power to the unit before servicing. Failure to follow this warning could result in serious injury or death.

Connect the thermostat using Figure 1 and Table 1 as a guide.

Procedure (Ensure there is no jumper wire at FP and F2)

1)Disconnect power to the unit.

2)Unscrew and remove the electrical control box’s cover.

3)Locate the Interface Connector (24 VAC terminal strip (See figure 1 at left).

4)Make the wire connections according to the configuration needed for

your unit (see above or page 40 for wiring diagrams). Use #18 gauge wire size.

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

6)Reattach the electrical control box’s cover.

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