White Rodgers 50A56-956 Manuel d'installation télécharger pdf (Page 6)

OPERATION

OPTION SWITCHES

The shunt jumper (E34) on the 50A56 control are used to

determine the length of the heat delay-to-fan-off periods. The

following table shows the time periods that will result from the

various positions.

E34

DELAY

OFF

BLWR

180

120

180

120

180

120

180

120

Heat Delay-to-Fan-Off

Shunt Jumper E34

Manual Fan Speed

Shunt Jumper E33

Factory Setting

120 Seconds

Factory Setting

HI COOL

LO COOL HEAT

60 Seconds

90 Seconds 180 Seconds

E33

SPEED

FAN

CONT

HI COOL

HEAT

LO COOL

HI COOL

HEAT

LO COOL

HI COOL

HEAT

LO COOL

HEAT MODE

In a typical system, a call for heat is initiated by closing the

Thermostat W contacts. This starts the control’s heating

sequence. The inducer blower and optional humidiﬁer are

energized. After the pressure switch is proven the ignitor is

energized and the warm-up time begins.

The ignitor is allowed to warm up for a 17 seconds initial

warm-up.

The120VACignitorswitha17-secondwarm-uptime

mustbeused.These ignitors are specially designed to heat

up quickly at a low voltage condition without overheating at a

high voltage condition. At the end of the ignitor warm-up time,

both valves in the manifold gas valve are opened. Flame must

be detected within 7 seconds.

When ﬂame is detected, the delay-to-fan-on period begins.

After the 30 seconds delay-to-fan-on period ends, the optional

electronic air cleaner is energized and the circulator fan is

energized at heat speed. When the thermostat is satisﬁed,

the gas valve is de-energized. After proof of ﬂame loss,

the selectable heat delay-to-fan-off period begins and the

inducer blower remains energized to purge the system for 15

seconds.

When the purge is complete, the inducer blower and

humidiﬁer are de-energized. After the delay-to-fan-off

period ends, the circulator fan and electronic air cleaner

are de-energized. If ﬂame is not detected, both valves are

de-energized, the ignitor is turned off, and the control goes

into the “retry” sequence. The “retry” sequence provides a

15- second purge period following an unsuccessful ignition

attempt (ﬂame not detected). After this wait, the ignition

sequence is restarted with a 27 second ignitor warm-up time.

The control will allow 2 retry periods before entering system

lockout.

If ﬂame is established for more than 10 seconds after ignition,

the controller will clear the ignition attempt (or retry) counter.

If ﬂame is lost after 10 seconds, it will restart the ignition

sequence.

During burner operation, a momentary loss of power of 50

milliseconds or longer will de-energize the main gas valve.

When power is restored, the gas valve will remain de-

energized and a restart of the ignition sequence will begin

immediately.

A momentary loss of gas supply, ﬂame blowout, or a shorted

or open condition in the ﬂame probe circuit will be sensed

within 2.0 seconds. The gas valve will de-energize and the

control will restart the ignition sequence.

Recycles will begin and the burner will operate normally if the

gas supply returns, or the fault condition is corrected.

If the control has gone into system lockout, it may be

possible to reset the control by a momentary power

interruption of one second or longer. Refer to SYSTEM

LOCKOUT FEATURES.

SINGLE STAGE COOL MODE

In a typical single stage cooling system, a call for cool is

initiated by closing the thermostat contacts, Y/Y2. This

energizes the control and the compressor. The cool delay-to-

fan-on period begins. After the delay period ends, the optional

electronic air cleaner is energized, and the circulator fan is

energized at high cool speed. After the thermostat is satisﬁed,

the compressor is de-energized and the cool mode delay-to-

fan-off period begins. After the delay-to-fan-off period ends,

the circulator fan and electronic air cleaner (optional) are

de-energized.

TWO STAGE COOLING MODE

In a typical two stage cooling system, a call for cool is initiated

by closing the Y1 thermostat contacts. This energizes the

control and ﬁrst stage of the compressor. The cool delay-to-

fan-on period begins.

After the delay period ends, the optional electronic air cleaner

is energized, and the low cooling circulator fan is energized.

When second stage cooling is called for the thermostat will

energize Y/Y2. This will energize the second stage of the

compressor and high cooling speed of the indoor circulating

fan. After the thermostat is satisﬁed, the compressor is de-

energized and the cool mode delay-to-fan-off period begins.

After the delay-to-fan-off period ends, the circulator fan and

electronic air cleaner (optional) are de-energized.

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White Rodgers 50A56-956 Manuel d'installation Page 6

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