Specifications

2
MOUNTING AND WIRING
All wiring should be installed by a qualified heating and air
conditioning contractor or licensed electrician, according to
local and national electrical codes and ordinances.
The control must be secured to an area that will experience a
minimum of vibration and remain below the maximum ambient
temperature rating of 176°F. The control is approved for
minimum ambient temperatures of -40°F.
When mounting the control, any orientation is acceptable.
Choose a location that will not damage, obstruct or place
stress on the control’s terminations, system wiring harness or
system components. After finding a suitable location, drill four
(4) 1/8” holes for mounting control. To ensure proper mounting
hole locations, use the control as a template. When drilling
the holes, take care so that the transformer, wiring harness or
other system components are not damaged. Four (4) #8 sheet
metal screws are provided to complete the installation.
Refer to the wiring diagram and wiring table when connecting
the 50M56U-751 control to other components of the system.
UL approved, 105°C rated 18 gauge, stranded, 2/64” thick
insulation wire is recommended for all low voltage safety circuit
connections.
UL approved 105°C rated 16 gauge min., stranded, 4/64”
thick insulation wire is recommended for all line voltage
connections.
After installation or replacement, follow appliance manufacturer’s
recommended installation or service instructions to ensure
proper operation.
Do not short out terminals on gas valve or primary
control. Short or incorrect wiring may damage the
thermostat.
CAUTION
!
WARNING
!
FIRE HAZARD
• Donotexceedthespeciedvoltage.
• Replaceexistingcontrolwithexactmodeland
dash number.
• Protectthecontrolfromdirectcontactwithwater
(dripping, spraying, rain, etc.).
• Ifthecontrolhasbeenindirectcontactwith
water, replace the control.
• Labelallwiresbeforedisconnectionwhenserv-
icing controls. Wiring errors can cause improper
and dangerous operation.
• Routeandsecurewiringawayfromame.
SHOCK HAZARD
• Disconnectelectricpowerbeforeservicing.
• Ensureproperearthgroundingofappliance.
• Ensureproperconnectionoflineneutralandline
hot wires.
EXPLOSION HAZARD
• Shutoffmaingastoapplianceuntilinstallation
is complete.
INSTALLATION
SPECIFICATIONS
ELECTRICAL RATINGS [@ 77°F (25°C)]:
Input Voltage: 25 VAC 50/60 Hz
Max.InputCurrent@25VAC: 0.45 amp
Relay Load Ratings:
Valve Relay: 1.5 amp @ 25 VAC 50/60 Hz 0.6 pf
Ignitor Relay: 6.0 amp @ 120 VAC 50/60 Hz (resistive)
Inducer Relay: 2.2 FLA–3.5 LRA @ 120 VAC
Circulator Relay: 14.5 FLA–25.0 LRA @ 120 VAC
Flame Current Requirements:
Minimum current to insure flame detection: 1 µa DC*
Maximum current for non-detection: 0.1 µa DC*
Maximum allowable leakage resistance: 100 M ohms
*Measured with a DC microammeter in the flame probe lead
OPERATING TEMPERATURE RANGE:
-40° to 176°F (-40° to 80°C)
HUMIDITY RANGE:
MOUNTING:
Surface mount multipoise
Timing Specs: (@ 60 Hz)
maximum
Flame Establishing Time: 0.8 sec
Flame Failure Response Time: 2.0 sec
Gases Approved: Natural, Manufactured, Mixed, Liquified
Petroleum, and LP Gas Air Mixtures are all approved for use.
TIMING SPECIFICATIONS
(All times are in seconds, unless noted otherwise
50M56-751
Pre-Purge 30
Initial Ignitor Warm-Up
(1st 64 attempts)
17
Maximum Ignitor Warm-Up 19
Ignition Activation Period 2
Trial for Ignition Period 4
Retries 2
Recycles 3
Valve Sequence Period 12
Interpurge 60
Post-Purge 25
Lockout Time 275
Heat Delay-To-Fan-On 25/60*
Heat Delay-To-Fan-Off 90/120*
Cool Delay-To-Fan-On 2
Cool Delay-To-Fan-Off 5/90*
Auto Reset 60 minutes
*These times will vary depending on option switch
position. See OPERATION section for further
information.