Emerson White-Rodgers 21M51U-843 Installation Instructions Manual

FAILURE TO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY
BEFORE INSTALLING OR OPERATING THIS CONTROL COULD CAUSE
PERSONAL INJURY AND/OR PROPERTY DAMAGE.
The 21M51U-843 is an aftermarket universal replacement
control kit for two-stage furnace products with PSC blower and
inducer motors.
This control replaces Goodman/Amana, Lennox/Armstong,
Trane/American Standard, and York applications.
TWINNING: 21M51U-843 can be twinned. Both control
boards must be from the same manufacturer for proper
functionality.
ELECTRICAL RATINGS:
Input Voltage: 120 VAC, 60 Hz (Class II transformer required)
Max. Input Current @ 24 VAC: 800mA + MV
Relay & Triac Load Ratings:
Gas Valve Relays: 1.5 amps @ 24 VAC, 60 Hz
Ignitor: 4.0 amps @ 132 VAC, 60 Hz
Inducer Relays: 2.2 FLA - 3.5 LRA @ 120 VAC
Circulator Relays: 14.5 FLA - 25.0 LRA @ 120 VAC
Humidifier Load: 1.0 A max @ 120 VAC
Electronic Air Cleaner Load: 1.0 A max @ 120 VAC
Flame Current Requirements:
Minimum current to ensure flame detection: 0.3 µA DC*
*Measured with a DC microammeter in series with flame
probe lead
Operating Temperature Range:
-40° to 175°F (-40 to 80°C)
Humidity Range:
5% to 93% relative humidity (non-condensing)
Gases Approved: Natural, Manufactured, Mixed, Liquid
Petroleum, and LP Gas Air Mixtures are all approved
for use.
21M51U-843
Universal Integrated Two-Stage
120V Hot Surface Ignition Control Kit
INSTALLATION INSTRUCTIONS
Parts included:
• 50M51-843 Integrated Furnace Control
• 21D64-2 HotRod Universal Ignitor Kit (120V)
• Trane Ignitor Mounting Bracket
• 3 – Mounting Screws
• 5 – Motor Lead Extensions
• Installation Instructions
white-rodgers.com
emerson.com
DESCRIPTION
SPECIFICATIONS
CAUTION
!
Risk of Electric Shock.
Disconnect electric power
to system until installation
is complete. Do not use on
circuit exceeding specified
voltage. Higher voltage will
damage control and could
cause shock or fire hazard.
This control is not intended
for use in locations where
it may come in contact with
water.
May cause flame rollout.
Shut off main gas to heat-
ing system until installa-
tion is complete.
PART NO. 37-7116001
1726