Trane Air Handler Fan Constantly Running

I have had good luck with the "titan hd" ones too.

i'd probably use steel hanger iron rather than plastic. mars probably has clips for them too.

you can test them with an ammeter, voltmeter, and light bulb. put it in series with the light bulb, measure the current through and voltage across the capacitor and calculate capacitance the same way you do with it connected to the compressor or blower motor.

they are smaller because they use more effective insulators that can be thinner and have the same dielectric strength. i remember learning about the starting/run caps in the 80's when my grandfather was telling us about how he had to replace the cap in his condenser. maybe they didn't fail as often but they were usually what failed.

that looks like it is a hard start rather than a replacement cap but you would have to trace and draw out what they did. the original bakelite case caps look like they are still connected. looks like they used that universal cap and a potential relay as a hard start

or maybe it is just a replacement for the compressor and fan run caps as i look at it more. i thought i saw 2 caps in bakelite cans but maybe what i though was a cap is just the contactor. buying caps that are the needed values is a lot less expensive than the universal cap, just buy the made in mexico like the titan hd

could be the start cap too. i'd probably replace both. or the potential relay although those usually don't go bad very often under normal conditions.

does the compressor hum but not start with the overload reset?

if the voltage of the universal cap is the same or less than the titan cap then that should be the right cap.

Is that Turbo 200 dated? That has a 5 year warranty!!! You may not have a bad capacitor. Here is a great video on how to check the capacitor while it is operating

Read the Amps thru the CAP to the start winding of the motor or compressor Amps x 2652 = X

Read the Volts across Cap and divide X ÷ volts across the CAP

That will be the Microfarad (uf or mfd) reading of that Capacitor. I started to include that actual test on all the maintenance calls for every PSC motor and compressor. My Capacitor sales went up by about 18% and there were less "NO AC" service calls from agreement (or club member) equipment. Found the bad ones before they caused a problem. Replaced them with the "Better" 5 year warranty Turbo 200 and increased customer satisfaction and parts sales on maintenance calls. WIN WIN WIN for everyone. The company, the service tech, and the customer all win!

check the resistance of the compressor windings, probably at the cap connections. should be under 50 ohms from c-r and c-s. probably under 10 ohms from c-r. could be a wire unplugged or burned somewhere in that rat's nest too.

Checking resistance (measuring Ohms) is always done with the item you're testing disconnected form anything else. If you have other stuff connected you will be measuring the resistance of all the connected items based on how they are connected (Parallel or in Series), and you don't want to know anything about the other stuff when measuring the windings of a compressor. You just want to measure the compressor motor's windings only

It should be 0 or near resistance between Red to Black, Red to Brown, Black to Brown. Now check each lead to ground. If its not grounded, then...

Put everything back the way it originally was . Start the condenser for a minute. Disconnect power and immediately check the windings again. You'll likely find them open. Do you have an ammeter with a min/max function to check amps on start? Is it near LRA Locked Rotor Amps?