White Rodgers Specifications and Operational Guidelines for the 50M56-743 Thermostat

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

Event	Definition	50M56-743
Pre-Purge	The period of time intended to allow for the dissipation of any unburned	30
	gas or residual products of combustion at the beginning of a furnace
	operating cycle prior to initiating ignition
Trial for Ignition	The period of time between initiation of gas flow and the action to	4
Period (TFI)	shut off the gas flow in the event of failure to establish proof of the
	supervised ignition source or the supervised main burner flame.
Ignition Activation	The period of time between energizing the main gas valve and	2
Period (IAP)	deactivation of the ignition means prior to the end of TFI
Retries	The additional attempts within the same thermostat cycle for ignition	2 times
	when the supervised main burner flame is not proven within the first
	trial for ignition period.
Recycles	The additional attempts within the same thermostat cycle for ignition	3
	after loss of the supervised ignition source or the supervised main
	burner flame.
Valve Sequence	Valve sequence period equals 4 seconds trial for ignition period x	12
Period	(1 initial try + 2 retries) + 12 seconds.
Interpurge	The period of time intended to allow for the dissipation of any unburned	60
	gas or residual products of combustion between the failed trial for
	ignition and the retry period.
Post-Purge	The period of time intended to allow for the dissipation of any unburned	25
	gas or residual products of combustion at the end of a furnace burner
	operating cycle. Post-purge begins at the loss of flame sense.
Lockout Time	ANSI standard rated module timing.	275
Heat Delay-To-Fan-On	The period of time between proof of the supervised main burner flame	30
	and the activation of the blower motor at Heat speed.
Heat Delay-To-Fan-Off*	The period of time between the loss of a call for heat and the	100/150*
	deactivation of the blower motor at Heat speed.
Cool Delay-To-Fan-On	The period of time after a thermostat demand for cool before energizing	6
	the circulator blower motor at Cool speed.
Cool Delay-To-Fan-Off*	The period of time between the loss of a call for cool and the	45
	deactivation of the blower motor at Cool speed.
Ignitor Warm-up	The length of time allowed for the igniter to heat up prior to the initiation	17
(1st 64 attempts)	of gas flow.
Maximum Ignitor	In the event of a retry, the warm-up time will be increased by one	19
Warm-up	second, up to a maximum of 19 seconds, and locked at that duration
Auto Reset	After one (1) hour of internal or external lockout, the control will auto-	60 minutes
	matically reset itself and go into an auto restart purge for 60 seconds.
Electronic Air Cleaner		Yes

*This time will vary depending on option switch position. The control is factory set at 150 seconds HEAT delay-to-fan-off. See OPERATION section for further information

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