Maintenance - York MA Installation Manual

Modular non-variable speed air handlers

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Technical manual (16 pages)

Table of Contents

MA SERIES - Air Handler Control Wiring

Typical A/C - Cooling only Applications

AIR HANDLER

THERMOSTAT

BOARD

Y / Y2

HUM

X / L

COM

FIGURE 10: Cooling Models with Electric Heat Wiring

1. "Y" Terminal on Air Handler Control Board must be connected for full CFM and applications requiring 60 second blower off delay for SEER enhancement.

2. Optional humidity switch - contacts open on humidity rise.

3. Remove HUM STAT Jumper on AH Control Board

4. MODE Jumper on AH control board should be set to A/C for air conditioners and HP for heat pumps.

5. To change quantity of heat during HP defrost cycle - Reverse connections at W1 & W2 on Air Handler Control Board

THERMOSTAT

X / L

FIGURE 11: Two-Stage Cooling Wiring

1. "Y" Terminal on Air Handler Control Board must be connected for full CFM and applications requiring 60 second blower off delay for SEER enhancement.

2. Optional humidity switch - contacts open on humidity rise.

3. Remove HUM STAT Jumper on AH Control Board

4. MODE Jumper on AH control board should be set to A/C for air conditioners and HP for heat pumps.

5. To change quantity of heat during HP defrost cycle - Reverse connections at W1 & W2 on Air Handler Control Board

SECTION X: MAINTENANCE

Filters must be cleaned or replaced when they become dirty. Inspect at

least once per month. The frequency of cleaning depends upon the

hours of operation and the local atmospheric conditions. Clean filters

keep unit efficiency high.

Unitary Products Group

1 - STAGE

AIR CONDITIONING