S-15A Resistance Check - Goodman *PH 16 Service Instructions Manual

Hide thumbs

Table Of Contents

Table of Contents

Enlarged version

SERVICING

CAPACITOR, START

SCROLL COMPRESSOR MODELS

Hard start components are not required on Scroll compressor

equipped units due to a non-replaceable check valve located in

the discharge line of the compressor. However hard start kits

are available and may improve low voltage starting characteris-

tics.

This check valve closes off high side pressure to the compres-

sor after shut down allowing equalization through the scroll

flanks. Equalization requires only about one or two seconds

during which time the compressor may turn backwards.

Your unit comes with a 180-second anti-short cycle to prevent

the compressor from starting and running backwards.

MODELS EQUIPPED WITH A HARD START DEVICE

A start capacitor is wired in parallel with the run capacitor to

increase the starting torque. The start capacitor is of the elec-

trolytic type, rather than metallized polypropylene as used in

the run capacitor.

A switching device must be wired in series with the capacitor

to remove it from the electrical circuit after the compressor

starts to run. Not removing the start capacitor will overheat the

capacitor and burn out the compressor windings.

These capacitors have a 15,000 ohm, 2 watt resistor wired

across its terminals. The object of the resistor is to discharge

the capacitor under certain operating conditions, rather than

having it discharge across the closing of the contacts within

the switching device such as the Start Relay, and to reduce

the chance of shock to the servicer. See the Servicing Section

for specific information concerning capacitors.

RELAY, START

A potential or voltage type relay is used to take the start ca-

pacitor out of the circuit once the motor comes up to speed.

This type of relay is position sensitive. The normally closed

contacts are wired in series with the start capacitor and the

relay holding coil is wired parallel with the start winding. As

the motor starts and comes up to speed, the increase in volt-

age across the start winding will energize the start relay hold-

ing coil and open the contacts to the start capacitor.

Two quick ways to test a capacitor are a resistance and a

capacitance check.