Transformer - TM-10-4110-262-13-P0178

TM 10-4110-262-13&P

0029 00

Evaporator Fan Cycling (non-cycling EF selector)

The evaporator fan selector is located in the RU PC board. Jumper 1 and 2 indexes the evaporator fan to cycle with

the compressor. Jumpers 2 and 3 index the evaporator fan to run continuously. The RU is factory set with jumper 1

and 2 connected.

Transformer

1. 700VA, 110/220 VAC primary and 24 VAC secondary transformer.

2. Secondary 24 VAC is obtained by adjoining two 12 VAC secondary windings in series.

3. 24 VAC secondary is wired directly to the full bridge rectifier circuitry and is converted to 24 VDC to power all

24 VDC components.

4. Primary power is fed with 208/230 VAC to L1 and L3.

5. 110 VAC is supplied to the light fixture from terminals H and H1 on the primary side of the

transformer.

Troubleshooting the Power Supply at the Transformer

1. 208/230 VAC

Using a multimeter, check for 208/230 VAC between H and H2.

If no voltage is present, check fuse 5 located in the RU control box.

If the fuse is good, check interconnecting wires.

2. 24 VAC

Using a multimeter, ensure primary voltage is present at the transformer (208/230 VAC).

Check for 24 VAC across terminals X1 and X4.

If 24 VAC is not present and the jumper wire is properly connected between terminals X2 and X3, then

replace the transformer.

3. Troubleshooting 24 VDC Circuitry

Using a multimeter, check for 24 VDC on C2 located in the RW control box at terminals 2 or 5 (positive) to

unit ground.

If no voltage is present, then locate the full bridge rectifier in the transformer/rectifier assembly box and

check for 24 VDC between terminals 2R and CH.

If 24 VDC is present, then troubleshoot wire between rectifier and C2 terminal.

If 24 VDC is not present, replace the full bridge rectifier.

0029 00-8