HHP PBNU-LD12N100 Panduan Petunjuk Instalasi - Halaman 14

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they will not be affecte d by radiant h eat. Inc rease the blower

speed to decr ease the temperature rise; decre ase the blower

speed to increase the rise.

All direct-drive b!owers have multi-speed blowers. Refer to the

unit wiring diagram and connect the blower motor for .the

desired speed. The blower motor speed taps are located in the

control box in the blower compartment.

ADJUSTMEN T OF FAN CONTROL SETTINGS

NOTE: Fan-On time is preset and not adjustable. When the

main gas valve is energized (ON), two wires carry 24v to

a smaff heater which controls fan-on timing.

To adjust the F an Off setting:

1. Tum the furnace on.

2. Let the furnace operate for 20 minutes.

3. Tum the furnace off.

4. Read the thermometer when the blower stops.

5. If this temperature is too high when the blower stops, lower

the fan off setting; if the temperature is too low, raise the

setting.

6. If adjustments are made to the fan off setting, check the

operation of the furnace by repeating the previous steps.

CAUTIO&: Vv'hen fan on and fan off adjustments are made, be

careful not to rotate the fan control dial. If the dial is a !lowed

to rotate, the control could be damaged and operate

erratically.

CHECKING

LIMIT CONTROL

With the main burners operating, cover all retum air grilles with

paper to restrict the flow of retutn air. In a few minutes, the

burners should be shut off by the limit control. Remove the

retum air restrictions. The main blower will cool the unit. The

limit switch should reclose and main burners relight after the

proper re-start period.

OPERATION

MAINTENANCE

SEQUE

E OF OPERATION

Hot Surface Ignition System

WARNING: Do n ot attempt to light this furnace by hand (with

a match or any other means). There may be a potential

shock hazard from the components of the hot surface

ignition system. The furnace can only be lit automatically

by its hot surface ignition system.

The following describes the sequence of operation of the

furnace. Refer to the schematic wiring diagram (pages 16 and

17) for component location.

Conti nuous Blower

On the cooling/heating units with fan switch, )Vhen the fan

switch is set in the ON position, a circuit is completed between

terminals R and· G of the thermostat. This energizes the 1

relay. Contact 1 R-1 closes and contact 1 R-2 opens. The motor

is energized through the black, high-speed tap. The blower

then operates on high speed.

Intermittent Blower

When the system switch is set on HEAT and the fan switch is

set on AUTO, and the room thermostat calls for heat, a circuit

is completed between terminals R and W of the thermostat.

This energizes the venter relay 3R, which energizes the venter.

When the proper amount of combustion air is being provided,

a pressure switch activates the SOE47 ignition control. A sec

ond and third pressure switch (2LP or 3LP and 4LP)(not used

in all models), the fusible link (FL) and the limit are in this circuit,

and must be in the closed position for the ignition control to b e

activated.

The 50E47 ignition control provides a 45-second warm-up

period. The gas valve then opens for four seconds.

·As gas starts to flow and ignition occurs, the flame sensor

begins its sensing function. If a flame is detected within four

seconds after ignition, normal furnace operation continues until

the thermostat circuit between R and W is opened. When the

supply air temperature reaches 115 to 125°F, the fan switch

closes.

When the thermostat circuit opens, the venter is deenergized,

along with the ignition control. With the ignition control deener

gized, the gas flow stops and the burner flames are extin

guished.

The blower motor continues to operate until the supply air

temperature drops to between 85 and 100°F. When this occurs.

the fan switch opens, de-energizing the blower motor. The

heating cycle is then complete, and the unit is ready for the stan

of the next heating cycle.

If flame is not detected within the four second sensing period.

the gas valve is de-energized. The 50E47 control is equipped

with a re-try option. This provides a 60-second wait following

an unsuccessful ignition attempt (flame not detected). After the

60 second wait, the ignition sequence is restarted with an

additional 10 seconds of igniter warm-up time. If this ignition

attempt is unsuccessful, one more re-try will be made before

lockout.

HOT SURFACE tGNITION CONTROL

50E47

All 50E47 controls will repeat the ignition sequence for a total

of five recycles if flame is lost within the first 10 seconds of

establishment.

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

the· controller will clear the ignition attempt (re-try) counter. If

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

quence. This can occur a maximum of five times.

During burner operation, a r:nomentary loss of power of 50

milliseconds or longer will drop out the main gas valve. When

the 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

0.8 seconds. The gas valve will de-energize and the control will

restart the ignition sequence after waiting 60 seconds.·

cles will begin and the bumer wHI operate normally if the gas

supply returns, or the fault condition is corrected prior to the

last ignition attempt. Otherwise, the control will lockout.

650.65-N2

Recy-