York W)036 THRU 060 Specifications download pdf (Page 42)

542300-YIM-A-1009

42 Johnson Controls Unitary Products

Operation

Cooling Sequence Of Operation

For the ZF series of units, the thermostat makes a circuit

between “R” and “Y1” for the first stage of cooling.

The call is passed to the Unit Control Board (UCB), which

then determines whether the requested operation is available

and, if so, which components to energize.

For gas heating, the UCB monitors the "W1" call but does not

handle the operation of the gas furnace. An ignition control

board controls the gas heater operation. For electric heat units,

the UCB passes the call to the electric heater. In both cases,

when the "W1" call is sensed, the indoor air blower is energized

following a specified heating delay.

If at any time a call for both heating and cooling are present, the

heating operation will be performed. If operating, the cooling

system is halted as with a completion of a call for cooling.

Heating always takes priority.

Continuous Blower

By setting the room thermostat fan switch to "ON," the supply

air blower will operate continuously.

Intermittent Blower

With the room thermostat fan switch set to "AUTO" and the

system switch set to either the "AUTO" or "HEAT" settings, the

blower is energized whenever a cooling or heating operation is

requested. The blower is energized after any specified delay

associated with the operation.

When energized, the indoor blower has a minimum run time of

30 seconds. Additionally, the indoor blower has a delay of 10

seconds between operations.

No Outdoor Air Options

When the thermostat calls for cooling, the low-voltage control

circuit from “R” to “Y1” and “G” is completed. The compressor and

condenser fan motor are energized. After completing the specified

fan on delay for cooling, the UCB will energize the blower motor.

Once the thermostat has been satisfied, it will de-energize Y1. If

the compressor has satisfied its minimum run time, the

compressor and condenser fan de-energize. Otherwise, the

unit operates the cooling system until the minimum run time for

the compressor has been completed. After the compressor de-

energizes, the blower is stopped following the elapse of the fan

off delay for cooling.

To be available, a compressor must not be locked-out due to a

high or low-pressure switch or freezestat trip and the anti-short

cycle delay (ASCD) must have elapsed.

Economizer With Single Enthalpy Sensor

When the room thermostat calls for cooling, the low voltage

control circuit from “R” to “G” and “Y1” is completed. The UCB

energizes the blower motor (if the fan switch on the room

thermostat is set in the “AUTO” position) and drives the

economizer dampers from fully closed to their minimum position.

If the enthalpy of the outdoor air is below the setpoint of the

enthalpy controller (previously determined), “Y1” energizes the

economizer. The dampers will modulate to maintain a constant

supply air temperature as monitored by the discharge air sensor.

If the outdoor air enthalpy is above the setpoint, “Y1” energizes

the compressor and condenser fan motor only.

Once the thermostat has been satisfied, it will de-energize “Y1”. If

the compressor has satisfied its minimum run time, the

compressor and condenser fan are de-energized. Otherwise, the

unit operates the cooling system until the minimum run times for

the compressor has been completed. After the compressor de-

energizes, the blower is stopped following the elapse of the fan

off delay for cooling, and the economizer damper goes to the

closed position. If the unit is in continues fan operation the

economizer damper goes to the min. position.

Table 18: Additional Static Resistance

Size

(Tons)

CFM Cooling Only

1. Add these values to the available static resistance in the respective Blower Performance Tables.

Economizer

2. Deduct these values from the available external static pressure shown in the respective Blower Performance Tables.

3. The pressure drop through the economizer is greater for 100% outdoor air than for 100% return air. If the resistance

of the return air duct is less than 0.25 IWG, the unit will deliver less CFM during full economizer operation.

Electric Heat kW

7 - 15 20 - 30

036 (3.0)

048 (4.0)

060 (5.0)

1000 0.08 0.07 0.04 0.06

1200 0.10 0.08 0.05 0.07

1400 0.12 0.09 0.06 0.08

1600 0.14 0.11 0.07 0.09

1800 0.16 0.13 0.08 0.11

2000 0.18 0.15 0.10 0.13

2200 0.20 0.17 0.12 0.15

2400 0.23 0.20 0.14 0.17

2600 0.26 0.23 0.16 0.20

2800 0.29 0.26 0.19 0.23

3000 0.32 0.30 0.22 0.26

1 2 ... 37 38 39 40 41 42 43 44 45 46 47 ... 57 58

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York W)036 THRU 060 Specifications Page 42

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