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PRODUCT DATA

68-0215-02

R8845U Universal Switching Relay

APPLICATION

The R8845U Universal Switching Relay provides intermediate 

switching of line- and low-voltage devices from a line- or 

lowvoltage controller. The R8845U may be used to replace 

several Resideo or competitive switching relays and is 

typically applied in hydronic heating systems.

FEATURES

• Replaceable, socketed relays.
• Replacement relay common to other hydronic replacement 

controls.

• Two troubleshooting LEDs.
• Push-to-test button.
• Replaceable transformer fuse.
• Low-voltage contact ratings for Powerpile® applications.
• Long-life DC relay drive control technology.
• Relays can be used with external 24 Vac or 24 Vdc supply, 

line-voltage control, or with internal 24V transformer.

• One model replaces several competitor models.
• One model replaces many Resideo models: R182A,B,C,J; 

R482A,B,C,J; R845A, R882A,B,C,J and RA832A. (See 

Table 1, Replacement Cross Reference.)

SPECIFICATIONS

IMPORTANT

The specifications given in this publication do not 

include normal manufacturing tolerances. There-

fore, this unit may not exactly match the listed spec-

ifications. Also, this product is tested and calibrated 

under closely controlled conditions, and some minor 

differences in performance can be expected if those 

conditions are changed.

Model:  

R8845U Universal Switching Relay with 24V control-

ler for switching one- or two-line voltage loads and one 

low-voltage load.

Electrical Ratings:

Voltage: 120 Vac, 60 Hz.

Thermostat Heat Anticipator Setting: 0.12A.

Transformer Ratings:

Primary: 120V, 60 Hz.

Secondary: 24 Vac, 12 VA maximum, 9 VA available for exter-

nal loads. Secondary protected by replaceable 1A auto-

motive fuse.

Contact Ratings:  

7.4 AFL, 44.4 ALR on each set of line-volt-

age contacts; maximum connected load is 2000 VA.

Switching Action:  

Two Spst, plus Powerpile® rated low-volt-

age Spst. If normally closed contacts are needed, use 

RA889A.

Temperature Ratings: 

Ambient: -20°F to 120°F (-29°C to 49°C).

Humidity Ratings:  

0 to 90% rh, non-condensing.

Electrical Connections:  

No. 8 captivated wire clamp screw 

terminals.

Finish:  

Zinc plated steel.

Knockouts:

Case Bottom: Three 1/2 in. (13 mm) for conduit box.

Case Top: One 7/8 in. (22 mm) for wiring.

Approvals:

Underwriters Laboratories Inc. Listed: File no. E4436, Guide 

no. XAPX. 

Canadian Underwriters Laboratories Listed: Guide no. 

XAPX7.

Summary of Contents for R8845U

Page 1: ...s unit may not exactly match the listed spec ifications Also this product is tested and calibrated under closely controlled conditions and some minor differences in performance can be expected if thos...

Page 2: ...onnections R8845U has lower output load rating Check load requirements use RA889A if normally closed contacts are required R182B 1 3 6 8 R182C 1 2 6 8 3 5 R182J L1 L2 4 7 If used to replace an R182J i...

Page 3: ...er right corner for the keyhole type mounting hole Screw it down within about 1 8 in 3 mm of the surface 3 Hang the relay on the screw position the case and start the bottom screw 4 Tighten both screw...

Page 4: ...PROTECTION AND DISCONNECT MEANS AS REQUIRED IF CONTROLLING TWO LOADS USE N O AND COM FOR LINE VOLTAGE LOAD A AND B FOR LINE OR LOW VOLTAGE LOAD IF USING LOW VOLTAGE USE A SEPARATE TRANSFORMER M14296 T...

Page 5: ...OL CASE MUST BE CONNECTED TO EARTH GROUND USE GROUNDING SCREW PROVIDED B1 IS 1 4 IN TAB TERMINAL 1 2 L7148A L8148A 2 1 M14300 3 3 X2 X1 N O COM L2 L1 W T R T X2 X1 N O COM L2 L1 W T R T X2 X1 N O COM...

Page 6: ...CASE MUST BE CONNECTED TO EARTH GROUND USE GROUNDING SCREW PROVIDED 1 1 20 VA M13315 R8888 1 G R8845U R T W T TO APPROPRIATE CONNECTIONS AS REQUIRED BY THE SYSTEM H1 H2 TYPICALLY CONNECTED TO T T OF...

Page 7: ...ake certain the relay controls the equipment as intended TROUBLESHOOTING Test Button This connection is the same as a call for heat connection between the R T and W T terminals Heat Call LED The LED s...

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