Indoor Blower Airﬂow, Condenser Fan Motors

Indoor Blower - Airﬂow

ThecurrentVert-I-Pak9,12,&18useadualshaft,permanent split capacitor, single speed motor to drive indoor blower and outdoor fan. Earlier model VERT-I-Pak units used 2-speed motors. The Vert-I-Pak 24 uses an individual, single shaft, permanent split capacitor, single speed motor for the indoor blower, and a separate motor drives the outdoor fan.

Different size (HP) motors and/or different diameter blower wheels are used in different models to obtain the required airﬂow.

Indoor Blower - Airﬂow

Different size (HP) motors and/or different diameter blower wheels are used in different models to obtain the required airﬂow.

Condenser Fan Motors

The current Vert-I-Pak 9, 12, & 18 units use a dual shaft, permanent split capacitor, single speed motor to drive indoor and outdoor fan. Earlier models used a 2-speed motor. The Vert-I-Pak 24 uses and individual, single shaft, permanent split capacitor, single speed motor for the outdoor fan, with a separate motor driving the indoor blower.

Blower Wheel Inspection

Visually inspect the blower wheel for the accumulations of dirt or lint since they can cause reduced airﬂ ow. Clean the blower wheel of these accumulations. If accumulation cannot be removed, it will be necessary to remove the blower assembly from the unit for proper wheel cleaning.

Cooling

A nominal 400 (350-450 allowable) CFM per ton of airﬂ ow is required to insure proper system operation, capacity, and efﬁ ciency. Factory-set blower speeds should provide the proper airﬂ ow for the size (Cooling capacity) of the unit when connected to a properly sized duct system.

Cooling (VEA/VHA 24)

When the thermostat is set for cooling mode (SYSTEM switch set to COOL and FAN switch to AUTO) a rise in room temperature will make It also causes a 24-volt signal on the “Y” thermostat conductor through the high pressure and low ambient switches energizing the compressor relay, turning on the compressor and outdoor fan motor. A 24-volt signal on the “G” thermostat terminal to the Fan Relay, turning on the indoor blower motor.

Heating (Electric)

When using electric heaters, select the blower speed that provides adequate airﬂ ow across the elements to prevent overheating and cycling on limit and/or premature failure. CHECK THE EXTERNAL STATIC PRESSURE, and then consult the AIR FLOW DATA to determine the ACTUAL air

ﬂow delivered for the factory selected fan speed. This will be especially important on change-outs using an existing duct system that may not have been properly sized to begin with.

Heating (VEA/VHA 24)

When the thermostat is set for heating mode (System switch set to HEAT and FAN switch to AUTO) it will make a 24- volt signal on the “B” thermostat terminal to energize the Reversing Valve Relay. A drop in room temperature, will make a 24-volt signal on the “W” thermostat terminal to the Defrost Thermostat, and “G” thermostat terminal to the Fan Relay. The Defrost Thermostat will determine whether the unit should run in Heat Pump, or Electric Heat, based on the outdoor temperature. (See Defrost Thermostat page 24)

External Static Pressure

External Static Pressure can best be deﬁned as the pressure difference (drop) between the Positive Pressure (discharge) and the Negative Pressure (intake) sides of the blower. External Static Pressure is developed by the blower as a result of resistance to airﬂow (Friction) in the air distribution system EXTERNAL to the VERT-I-PAK cabinet.

Resistance applied externally to the VERT-I-PAK (i.e. duct work, coils, ﬁ lters, etc.) on either the supply or return side of the system causes an INCREASE in External Static Pressure accompanied by a REDUCTION in airﬂ ow.

External Static Pressure is affected by two (2) factors.

1.Resistance to Airﬂ ow as already explained.

2.Blower Speed. Changing to a higher or lower blower speed will raise or lower the External Static Pressure accordingly.

Theseaffectsmustbeunderstoodandtakenintoconsideration when checking External Static Pressure/Airﬂow to insure that the system is operating within design conditions.

Operating a system with insufﬁ cient or excessive airﬂ ow can cause a variety of different operating problems. Among these are reduced capacity, freezing evaporator coils, premature compressor and/or heating component failures. etc.

System airﬂ ow should always be veriﬁ ed upon completion of a new installation, or before a change-out, compressor replacement, or in the case of heat strip failure to insure that the failure was not caused by improper airﬂ ow.