Install Instructions

ManualsBrandsMcdonnell & Miller ManualsHeating SuppliesUWH-RB-24A Universal Wiring Harness

UWH-RB-24

Universal Wiring

Harness

The Universal Wiring Harness includes a cable

connector and three 'Y' harnesses, which allow

an RB-24 LWCO to be connected to most

residential hot water boilers having a 24 volt

burner circuit.

• Before using this product read and understand instructions.

• Save these instructions for future reference.

• All work must be performed by qualified personnel trained in the proper application,

installation, and maintenance of plumbing, steam, hot water, and electrical equipment

and/or systems in accordance with all applicable codes and ordinances.

•

To prevent electrical shock , turn off the electrical power before making electrical connections.

• This low water cut-off must be installed in series with all other limit and operating controls

installed on the boiler. After installation, check for proper operation of all of the limit and

operating controls, before leaving the site.

• We recommend that secondary (redundant) Low Water Cut-Off controls be installed on all

boilers with heat input greater than 400,000 BTU/hour. At least two controls should be

connected in series with the burner contro l circuit to provide safety redundancy protection

should the boiler experience a low water condition. Moreover, at each annual outage, the

low water cut-offs should be dismantled, inspected, cleaned, and checked for proper

calibration and performance.

Failure to follow this warning could cause property damage, personal injury or death.

WARNING

UWH-RB-24SUWH-RB-24A

McDonnell & Miller

Installation & Maintenance

Instructions

MM-274(C)

Summary of content (8 pages)

PAGE 1
McDonnell & Miller Installation & Maintenance Instructions MM-274(C) UWH-RB-24 Universal Wiring Harness UWH-RB-24A UWH-RB-24S The Universal Wiring Harness includes a cable connector and three 'Y' harnesses, which allow an RB-24 LWCO to be connected to most residential hot water boilers having a 24 volt burner circuit. WARNING • Before using this product read and understand instructions. • Save these instructions for future reference.
PAGE 2
RB-24 SPECIFICATIONS Temperature: Storage: -40˚F to 120˚F (-40˚C to 49˚C) Ambient: 32˚F to 120˚F (0˚C to 49˚C) Humidity: 85% (non-condensing) M a x i mum Water Pressure: 160 psi (11.2 kg/cm2) M a x i mum Water Temperature: 250˚F (121˚C) Electrical Ratings Voltage Power Consumption Switching Capacity 24 VAC 2.5 VA 2A at 24 VAC E n closure Rating: NEMA 1 General Purpose Do not use Model RB-24 on IMPORTANT: steam boilers. Do not use on millivolt IMPORTANT: systems.
PAGE 3
IMPORTANT: Universal wiring harness adaptors are now available for use with systems hav i n g modular plug-on bu rner controllers and vent dampers (sold separa t e l y ) . The UWH-RB-24A is for use on hot water boilers that have a vent damper. P/N 144681 UWH-RB-24A The UWH-RB-24S is for use on hot water boilers that have a transformer plug connection on the aquastat. P/N 144682 UWH-RB-24S The UWH-RB-24L is for use on hot water boilers that have a control panel connection.
PAGE 4
Option 1 - Damper 'Y' Harness NOTE This 'Y' Harness can only be used with vent dampers with 6-pin connectors. A. Remove connector of damper wiring harness from connector on control. B. Plug connector of UWH-RB-24 damper 'Y' harness to connector on control. C. Plug connector of UWH-RB-24 damper 'Y' harness to connector of damper wiring harness. Option 2 - Transformer 'Y' Harness with GREEN Color Tubing A. Remove connector of boiler wiring harness from Aquastat transformer connector. B.
PAGE 5
Option 3 - Transformer 'Y' Harness with GREEN Color Tubing A. Remove connector of boiler wiring harness from Aquastat transformer connector. B. Plug connector of boiler wiring harness to connector of 'Y' harness with GREEN color tubing. C. Plug connector of 'Y' harness with GREEN color tubing to Aquastat transformer connector. Option 4 - Transformer 'Y' Harness with BLUE Color Tubing A. Remove connector of boiler wiring harness from boiler control transformer connector. B.
PAGE 6
STEP 4 - Connection to RB-24 a. Plug connector of cable into connector of RB-24. b. Plug connector of 'Y' harness into connector of cable. RB-24E-L Connector with Gray Color Tubing for Control Panel Connection a. Remove jumper plug from plug-in connector on control panel. b. Plug connector of wiring harness into plug-in Connector on control panel.
PAGE 7
STEP 5 - Testing a. Before filling the system, turn on the electric power to the boiler. The low water cut-off's green "Power On" LED should be illuminated. With the room thermostat set on "heat", confirm that the burner will not operate without water in the system. The low water cut-off's red LED should be illuminated. NOTE: The burner will come on briefly (1 second or less) and then shut off to verify proper operation. b. Fill the system with water.
PAGE 8
McDonnell & Miller TROUBLESHOOTING: If control fails to operate, follow the following diagnostic checks. 1. Check to be sure that the water level in the boiler is at or above the level of the probe. 2. Re-check all wiring to ensure proper connections as specified in boiler manufacturers wiring diagrams. 3. Check to ensure that Teflon tape has not been used on the threaded connection of the probe to the boiler. 4. Check the quality of the boiler to ensure adequate conductance.