York W)036 THRU 060 Specifications download pdf (Page 50)

542300-YIM-A-1009

50 Johnson Controls Unitary Products

Adjustment Of Temperature Rise

The temperature rise (or temperature difference between the

return air and the heated air from the furnace) must lie within

the range shown on the rating plate and the data in the Gas

Heat Application Table 10.

After the temperature rise has been determined, the cfm can be

calculated as follows:

After about 20 minutes of operation, determine the furnace

temperature rise. Take readings of both the return air and the

heated air in the ducts (about six feet from the furnace) where

they will not be affected by radiant heat. Increase

the blower

cfm to decrease

the temperature rise; decrease the blower cfm

to increase the rise. Refer to the In Door Blower Specification

Table 16.

Charging The Unit

ZF036 and 048 units use Thermal Expansion Devices; ZF060

Units use a Fixed Orifice for Refrigerant Control. Charge all

units to 12° subcooling.

Troubleshooting

On calls for cooling, if the compressors are operating but the

supply air blower motor does not energize after a short delay

(the room thermostat fan switch is in the “AUTO” position).

1. Turn the thermostat fan switch to the ON position. If the

supply air blower motor does not energize, go to Step 3.

2. If the blower motor runs with the fan switch in the ON

position but will not run after the compressor has energized

when the fan switch is in the AUTO position, check the

room thermostat for contact between R and G in the AUTO

position during calls for cooling.

3. If the supply air blower motor does not energize when the

fan switch is set to ON, check that line voltage is being

supplied to the contacts of the M2, contactor, and that the

contactor is pulled in. Check for loose wiring between the

contactor and the supply air blower motor.

4. If M2 is pulled in and voltage is supplied to M2, lightly touch

the supply air blower motor housing. If it is hot, the motor

may be off on internal protection. Cancel any thermostat

calls and set the fan switch to AUTO. Wait for the internal

overload to reset. Test again when cool.

5. If M2 is not pulled in, check for 24 volts at the M2 coil. If 24

volts are present at M2 but M2 is not pulled in, replace the

contactor.

6. Failing the above, if there is line voltage supplied at M2, M2

is pulled in, and the supply air blower motor still does not

operate, replace the motor.

7. If 24 volts is not present at M2, check that 24 volts is

present at the UCB supply air blower motor terminal,

“FAN”. If 24 volts is present at the FAN, check for loose

wiring between the UCB and M2.

8. If 24 volts is not present at the “FAN” terminal, check for 24

volts from the room thermostat. If 24 volts are not present

from the room thermostat, check for the following:

a. Proper operation of the room thermostat (contact

between R and G with the fan switch in the ON position

and in the AUTO position during operation calls).

b. Proper wiring between the room thermostat and the

UCB.

c. Loose wiring from the room thermostat to the UCB.

9. If 24 volts is present at the room thermostat but not at the

UCB, check for proper wiring between the thermostat and

the UCB, i.e. that the thermostat G terminal is connected to

the G terminal of the UCB, and for loose wiring.

10. If the thermostat and UCB are properly wired, replace the

UCB.

On a call for cooling, the supply air blower motor is operating

but the compressor is not (the room thermostat fan switch is in

the “AUTO” position).

1. If installed, check the position of the economizer blades. If

the blades are open, the economizer is providing free

cooling and the compressors will not immediately operate.

If both stages of cooling are requested simultaneously and

the economizer provides free cooling, following a short

delay the compressor will be energized unless it is locked

out, unless this option has been disabled through computer

communications.

2. If no economizer is installed or the economizer is not

opening to provide free cooling and the compressor does

not energize on a call for cooling, check for line voltage at

Troubleshooting of components may require opening

the electrical control box with the power connected to

the unit. Use extreme care when working with live

circuits! Check the unit nameplate for the correct line

voltage and set the voltmeter to the correct range before

making any connections with line terminals.

When not necessary, shut off all electric power to the

unit prior to any of the following maintenance

procedures so as to prevent personal injury.

Label all wires prior to disconnection when servicing

controls. Wiring errors can cause improper and

dangerous operation which could cause injury to person

and/or damage unit components. Verify proper

operation after servicing.

CFM

Btuh Input x 0.8

108..xFTempRise

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York W)036 THRU 060 Specifications Page 50

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