42-102664-10 – CONTACTOR (1 POLE, 24V COIL, 40 AMP, SCREW & LUG TERMINALS)

Genuine PROTECH single-pole contactor with a 24 VAC coil, listed by Rheem as “Contactor – 40A 1-Pole (24V coil)” and manufactured by Zettler. Rheem publishes a 40 A motor FLA and 240 A motor LRA rating at 230 V, with a 50 A resistive rating at 230 V, 460 V and 575 V. Rheem’s parts catalog identifies this part as used in Rheem RA17 and Ruud UA17 equipment. Note: Rheem now lists this part as obsolete and shows 42-109499-10 as the replacement part number.

Specifications published by the manufacturer. Source: manufacturer documentation.

Specs

• BrandPROTECH
• Number of Poles1
• Coil Voltage24 VAC
• Motor FLA Rating at 230V40 A
• Motor LRA Rating at 230V240 A
• Resistive Rating at 230V50 A
• Terminal ConnectionsScrew & lug
• Genuine Factory OEM PartYes
• UPC662766505054
• Rheem-listed Replacement Part42-109499-10
• Where UsedRheem RA17 / Ruud UA17

Cross-reference numbers

This part replaces the following OEM and aftermarket numbers:

• 42-109499-06
• CONT1P025024V
• 42-109499-10
• GSZ140421KF
• ML42-102664-10

Not sure if your number matches? Call (214) 340-9421 or bring the old part in — bench-testing is free.

The outdoor unit hums or does nothing at all. Could it really be just the contactor?

Very often, yes. Pitted, carboned or welded contacts are one of the most common no-cool causes we see, and a contactor costs a fraction of the compressor or motor people assume has failed. Kill power, pull the cover and look at the contact faces. Silver-gray and slightly rough is normal. Black, cratered or fused together means replace it. Ants and mud dauber nests packed into the contactor are a Dallas classic too.

How do I check it?

With the thermostat calling you should read about 24 volts across the coil terminals. Coil voltage present and the contactor not pulling in means a bad coil. Contactor pulled in but the compressor dead means you measure voltage drop across each closed pole - more than a couple of volts across a closed contact means the contact is burnt, even though it looks like it is working.

What has to match on a replacement?

Coil voltage, pole count, FLA and horsepower rating, plus the physical footprint and terminal style. A 24 volt coil, 30 amp, 2 pole unit covers most residential condensers, but definite purpose contactors with a single pole break and a jumpered leg are common on some brands. Bring the old one in.

Should I change the contactor when I change a compressor or motor?

Yes. Copeland calls for inspecting the contactor any time a compressor is replaced, and welded contacts that single phase a compressor are exactly how a lot of them die.