Operating Sequence; Heating Cycle; Cooling Cycle; Fan Mode - Nordyne CMF95 Series Installation Instructions Manual

OPERATING SEQUENCE

The operating sequences for the heating, cooling, and
fan modes are described below. Refer to the field and
furnace wiring diagrams: (Figures 15 & 16, page 31) and
(Figure 18 page 28).

Heating Cycle

1. The thermostat calls for heat by energizing the W
terminal with 24VAC.
2. The control verifies the pressure switch is open.
3. If the pressure switch is open, the control energizes the
inducer and waits for the pressure switch to close. The
pressure switch must close within 10 seconds.
4. The control runs the inducer for a 30 second pre-purge.
5. The control energizes the Hot Surface Igniter (HSI)
output for the appropriate warm-up time limit.
6. The control energizes the main gas valve for 3 seconds.
7. If the flame proved and ignites the gas, the control de-
energizes the HSI. The gas valve and inducer remains
energized. The control goes to blower on delay.
8. If flame is present, the control energizes the blower on
the selected HEAT speed 30 seconds after the gas valve
opened. The gas valve and inducer remain energized.
9. When the thermostat demand for heat is satisfied, the
control de-energizes the gas valve. The Inducer output
remains on for a 30 second post-purge period.
10. Blower off timing begins when the thermostat is
satisfied.The control will operate at the selected HEAT
speed of 60, 90, 120, or 180 seconds. If the blower
off delay jumper is not present, the fan should still
operate for 120 seconds at the selected HEAT speed.
The Indoor blower motor is de-energized after a blower
off delay as selected by the movable jumper.

Cooling Cycle

1. The thermostat calls for cooling by energizing the Y
terminal with 24VAC.
2. The control energizes the blower in cooling speed and
sends 24VAC to the contactor in the condensing unit
3. When the thermostat removes the call for cooling, the
contactor in the outdoor condensing unit is de-energized
and the control continues to run the fan for a period of
60 seconds.

Fan Mode

• When the thermostat energizes the G terminal for
continuous fan (without calling for heat or cooling), the
indoor fan is energized on the selected FAN speed.
• If a call for cooling occurs during continuous fan, the
blower will switch over to the selected COOL speed.
• If the W terminal receives a call for heat during
continuous fan, the blower will de energize.
• A call for fan is ignored while in lockout.

MAINTENANCE

Proper maintenance is most important to achieve the best
performance from a furnace. Follow these instructions for
years of safe, trouble free operation.
WARNING:
ELECTRICAL SHOCK, FIRE OR EXPLOSION
HAZARD
Failure to follow safety warnings exactly could
result in serious injury or property damage.
Improper servicing could result in dangerous
operation, serious injury, death or property
damage.
• Before servicing, disconnect all electrical
power to furnace.
• When servicing controls, label all wires prior
to disconnecting. Reconnect wires correctly.
• Verify proper operation after servicing."
AVERTISSEMENT:
RISQUEDECHOCÉLECTRIQUE,D'INCENDIE
OU D'EXPLOSION
Le non-respect des avertissements de sécurité
pourrait entraîner un fonctionnement dangereux
de l'appareil, des blessures graves, la mort ou
des dommages matériels.
Un entretein incorrect pourrait entraîner un
fonctionnement dangereux de l'appareil, des
blessures graves, la mort ou des dommages
matériels
• Couper toute alimentation électrique au
générateur d'air chaud avant de prodéder
aux travaux d'entretein.
• Au moment de l'entretien des commandes,
étiquetez tous les fils avant de les
débrancher. S'assurer de les raccorder
correctement.
• S'assurer que l'appareil fonctionne
adéquatement aprés l'entretien.
• These maintenance instructions are primarily intended
to assist qualified technicians experienced in the proper
maintenance and operation of this appliance.
• Always close the door on the furnace after servicing
or cleaning/changing the filters. Do not operate the
furnace without the door closed.
• Verify the thermostat is properly installed and will
not be affected by drafts or heat from lamps or other
appliances.
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