HHP PBNU-LD20N140 Manuale di istruzioni per l'installazione - Pagina 12

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Fusi ble Unk Con tro l

This control is m ounte d in th e burner compartment. If the

temperature in the bur ner compart ment exceeds 306°F, the

cir?ui

. t to the ig . n iter contr ol and the gas valve is de-energized.

Th1s 1s·a one-t1me fusible link type control. Before the furnace

can operate again, the control must be replaced. The operation

of this control indicates a possible burner flame r<?ltout . condi

tion. The combustio n air blower and the combustion a1r pres

sure switch should be checked for proper operation.

Pressure Switches

This furnacels supplied with pressure switches which monitor

the flow through ths-combustion air/vent piping system. These

switches de-energize the ignition control module and the gas

valve if any of the following conditions are present.

1. Blockage of combustion air piping or terminal.

2. Blockage of vent piping or terminal.

3. Failure of combustion air blower motor.

4. Blockage of condensate drain piping.

START-UP AND ADJUSTMENTS

The initial start-up of the furnace requires the following addi

tional procedures:

1. When the gas supply is' initially connected to the furnace,

the gas piping may be full of air. In order to purge this air,

it is recommended that the ground union be loosened until

the odor of gas is detected. When gas is detected, imme

diately retighten the union and check for leaks. Allow five

minutes for any gas to dissipate before continuing with the

start-up procedure.

WARNING: Be sure proper ventilation is available to dilute and

carry away any vented gas.

2. The condensate trap must be filled with water before

putting the furnace into operation. The recommended

procedure is as follows:

a Disconnect the condensate drain hose from the con

densate drain outlet fitting (see Figure 10 for location

of this hose connection).

b. Elevate this hose above trap level and fill with water

using a funnel. Drain excess water into a container.

c. Replace the condensate drain hose and clamps.

3. All electrical 'connections made in the field and in the

factory should

checked for proper tightness.

bEi

IGNITION SYSTEM CHECKOUT/ADJUSTMENT

1. Tum gas supply OFF at external gas valve or main gas

valve (see F. i gure

12).

that 24 volts is available across terminal C and R on the

transformer.

2. Check ignition module operation as follows:

a. Set the thermostat to "heat". Tum thermostat setting

above room temperature to call for hea1.

b . . Through burner box observation ports watch-for the hot

surface igniter to begin glowing.

c. If glow is seen, turn the thermostat down (below room

temperature). Hot surface igniter should stop glowing.

3. Tum the gas supply ON at external valve and main gas valve.

4. Set the-thermostat above room temperature to call for h

5 .

SystE)m �tart-Lip will occur

Unitary Producls Group

Turnelectrical power ON. Check

follows:

a. Venter motor will

a fter venter

start-up, th e hot suriace igniter will glow

a bout 45

seconds.

b. After warm-up

(open) the

ma1n gas

e power

NOTE: Burner ignition may not be s atisfactory on first start-up

due to residual air in gas line , or un til gas pressure

fold} or burner air shutters are adjusted.

6. With furnace in operation, paint the

gasket lines with a rich soap and water··solution. Bubble

indicate a gas leak. T ake appropriate steps to

leaks. If the leak persists, replace the co

WARNING: DO NOT omit this test! NEVER use

check for gas leaks.

ADJUSTMENT OF MANIFOLD

1. Tum gas off at main gas valve. Remove 1/8" plug in the main

gas valve body and install proper manometer tube adapter

fitting. Connect line from gas valve tap to manometer

2. Refer to Figure 12 for location of pressure regulator adjust

ment cap and screw on main gas valve.

Inlet

Wrench

Boss

Manual Gas

Control Knob

FIGURE

12- GAS VALVE

NOTE: The screw-off cap for the pressure regulator must be

moved

entirely to gain access to the adjustment

ing or tifjltening the cap cbes not adjust the flow of gas.

3. Turn gas and electrical supplies ON. Start furnace and

observe manifold pressure on manometer.

4. Adjust manifold pressure by adjusting gas valve reg'u. ! ator

screw: for natural gas, set at 3.5" W.C.; for propane

gas, set at 10.0" W.C.

If gas valve regulator is turned in, or clockwise, manifold

pressure is increased. If screw is turned out, or counter

clockwise, manifold pressure will decrease.

Natural Gas

WARNING: If manifold pressure is too high, an over-fire con-

dition exists which could cause heat exchanger failure. If

the manifold pressure is too low, sooting and eventual

clogging of the heat exchanger could occur.

WARNING: Once the correct gas pressure to the burners has

been established, tum the gas valve knob to OFF and turn

the electrical supply switch to OFF; then remove the-

pressure tap at the gas valve and re-install the plug, using

a compound

{

on the threads) resistant to the action of LP

gases.

start and

come up to speed. Sh ortly

le will energize

cycle, ignition m

valve for four seconds.

the igniter is shut otf .

pipe joints

AS PRESS

Wiring

Jum per

Termin als

Press. Reg.

Outlet

Under Cover

Pressure

Screw

Tap

screw

3.5" w.c.

10.0" w.c.

650 65-N2

for

At the same

{mani

and valve

the

stop

a flame

URE

Loosc:n

{LP)