Goodmans CPG SERIES Manual Do Utilizador

21

A pressure switch stuck open can be caused by a faulty pres-
sure switch, faulty wiring, a disconnected or damaged hose,
a blocked or restricted flue, or a faulty induced draft blower.

If the control senses an open pressure switch during the pre-
purge cycle, the induced draft blower only will be energized.
If the pressure switch opens after ignition has begun the gas
valve is deenergized, the circulator blower heat off cycle be-
gins, and the induced draft blower remains on.  The diagnos-
tic fault code is two flashes.

A stuck closed pressure switch can be caused by a faulty
pressure switch or faulty wiring.  If the control encounters a
pressure switch stuck closed, the induced draft blower re-
mains off.  The diagnostic LED code for this fault is three (3)
flashes.

If the primary limit switch opens, the gas valve is immediately
deenergized, the induced draft and air circulating blowers
are energized.  The induced draft  and air circulator blowers
remain energized until the limit switch recloses.  The diag-
nostic fault code for an open limit is four (4) flashes.

A primary limit will open due to excessive supply air tempera-
tures.  This can be caused by a dirty filter, excessive duct
static, insufficient air flow, or a faulty limit.  Check filters, total
external duct static, blower motor, blower motor speed tap
(see wiring diagram), and limit.  This limit will automatically
reset once the temperature falls below a preset level.

If flame is detected with the gas valve deenergized, the com-
bustion and air circulator blowers are energized.  The diag-
nostic fault code is five (5) flashes for this condition.  The
control can be reset by removing the power supply to the unit
or it will automatically reset after one hour.  Miswiring is the
probable cause for this fault.

The automatic ignition control has a built-in feature that pre-
vents damage to the compressor in short cycling situations.
In the event of intermittent power losses or intermittent ther-
mostat operation, the ignition control will delay output to the
compressor contactor for three minutes from the time power
is restored.  (Compressor is off a total of three minutes).  The
diagnostic LED will flash six (6) times to indicate the com-
pressor contactor output is being delayed.

NOTE:   Some electronic thermostats also have a built-in
compressor short cycle timer that may be longer than the
three minute delay given above.  If you are using an electronic
thermostat and the compressor has not started after three
minutes, wait an additional five minutes to allow the thermostat
to complete its short cycle delay time.

It is the responsibility of the contractor to adjust the gas input
to the unit. The input rate can be calculated by using the
formula:

I

NPUT Btu/Hr = 

3600 x HV

T 

WHERE:
HV = Heating value of fuel = Btu/ft  of gas
T = Time in seconds per ft  of gas flow as read from gas meter

3

3

Adjust input rate by varying the adjustment of the gas pres-
sure regulator on the gas valve. All adjustments must be made
with furnace operating at high fire and at normal operating
temperature. Clockwise (P) rotation of the pressure regula-
tor screw increases pressure and gas flow rate. Turn screw
counterclockwise (Q) to decrease pressure and gas flow rate.
After adjustment the furnace temperature rise must be within
the range specified on the unit data plate. NOTE: Thermal
efficiency of the furnace is a product efficiency rating deter-
mined under continuous operating conditions independent
of any installed system.

Pressure Regulator

Adjustment 

(Under Cap Screw)

Gas Valve

On/Off

Selector

Switch

INLET

OUTLET

Inlet Pressure

Tap

Outlet Pressure

Tap