White Rodgers 1F85-277 Guía para resolver problemas descargar pdf (Pagina 77)

OPTION SWITCHES

The option switches on the 50A62-820 control are used to

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

following table shows the time periods that will result from the

various switch positions.

HEAT MODE

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

thermostat contacts. This starts the 50A62 control’s heating

sequence. The inducer blower and humidiﬁer are energized

(if there is an optional electronic air cleaner on the system,

the humidiﬁer is not energized until the electronic air cleaner

is energized). The 768A Silicon Nitride ignitor is powered

within one second.

This controller has an adaptive algorithm that reduces the

ignitor temperature to slightly greater than the minimum

temperature required to ignite gas in each particular applica-

tion. The control measures the line voltage and determines

an initial ignitor temperature setting based on the measure-

ment. After each successful ignition, the control lowers the

ignitor temperature slightly for the next ignition attempt. The

control continues to lower the ignitor temperature until ignition

does not occur, and the control goes into retry mode. For the

second attempt to ignite gas within the same call for heat,

the control increases the ignitor temperature to the value it

was on the third previous successful ignition. After ignition is

successful, the control sets the ignition temperature at this

value for the next 255 calls for heat, after which the control

repeats the adaptive algorithm. The control is constantly mak-

ing adjustments to the ignitor temperature to compensate for

changes in the line voltage.

The 80 VAC Silicon Nitride ignitor manufactured by

White-Rodgers must be used. These ignitors are specially

designed to operate with the 50A62’s adaptive ignition routine

to ensure the most efﬁcient ignitor temperature.

HEAT delay-

to-fan-off:

Set switch

#1 #2

180 sec.

120 sec.

90 sec.

60 sec.*

On On

On Off

Off On

Off Off

OPTION SWITCH POSITIONS

* Factory setting

OPERATION

COOL MODE

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

thermostat contacts. This starts the 50A62 control’s cool-

ing sequence. The compressor is energized and the cool

mode delay-to-fan-on period begins. After the delay-to-fan-on

period ends, the circulator fan is energized at cool speed.

The electronic air cleaner (optional) is also energized. 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.

MANUAL FAN ON MODE

If the thermostat fan switch is moved to the ON position, the

circulator fan (fan speed) and optional electronic air cleaner

are energized. When the fan switch is returned to the AUTO

position, the circulator fan and electronic air cleaner (optional)

are de-energized.

SYSTEM LOCKOUT FEATURES

When system lockout occurs, the gas valve is de-energized,

the circulator blower is energized at heat speed, and, if ﬂame

is sensed, the inducer blower is energized for 5 seconds.

The diagnostic indicator light will ﬂash or glow continuously to

indicate system status. (System lockout will never override

the precautionary features described above.)

To reset the control after system lockout, do one of the

following:

1. Interrupt the call for heat at the thermostat for at least

one second (if ﬂame is sensed with the gas valve de-

energized, interrupting the call for heat at the thermostat

will not reset the control).

2. Interrupt the 24 VAC power at the control for at least one

second. You may also need to reset the ﬂame rollout

sensor switch.

3. After one hour in lockout, the control will automatically

reset itself.

DIAGNOSTIC FEATURES

The 50A62-820 control continuously monitors its own opera-

tion and the operation of the system. If a failure occurs, the

DIAG 1 and DIAG 2 LEDs will indicate a failure code as

shown below.

SAFETY CIRCUIT

DIAG 1 DIAG 2

Limit Control Slow Flash On

Pressure Switch Off Slow Flash

Watch Guard - Burners Alternate Alternate

Failed to Ignite Slow Flash Slow Flash

Flame Sensed Without

Slow Flash Off

Valve Energized

Roll Out Open or 9-Pin

On Slow Flash

Connector Disconnected

Bad Board On On

Power On

Simultaneous Simultaneous

Slow Flash Slow Flash

Low Flame Slow Flash Slow Flash

Reverse Polarity Fast Flash Slow Flash

Low Voltage or Alternate Alternate

Ignitor Disconnected Fast Flash Fast Flash

Heat Demand

Simultaneous Simultaneous

Fast Flash Fast Flash

INTEGRATED

FURNACE CONTROLS

WIRING AND

CONFIGURATION

www.white-rodgers.com

200

TECHNICAL HELP

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