How to Fix a Broken Air Conditioner | 220v Contactor Relay

Agreed, the component is under rated from the start. If you look at a datasheet from a 25A SSR from a better company you will find something like de-rating curves which really show that as you move from the ideal conditions (20C temp, infinite heatsink) you should only use a smaller load. It is pretty easy to reach a limit of half the max load in normal conditions.

I am certainly not suggesting HVACR techs engage in performing work outside of their skills or licensures, but, in many cases, being able to identify the problem and making the repair are two different things.

“Twelve-gauge wire is good for 20 amps, 10-gauge wire is good for 30 amps, 8-gauge is good for 40 amps, and 6-gauge is good for 55 amps,” and “The circuit breaker or fuse is always sized to protect the conductor [wire].”

It should be mentioned that any of us that have been working in commercial/industrial settings should be familiar and certified under NFPA70E. This includes, but is not limited to, how to work as safe as possible with hazardous energy sources, what the proper protection is for various levels and what is considered “safe” (working distance, approach distance, protection level, etc).

The melted solder was probably a secondary failure. When SSRs fail they often turn into heaters as his did and the heat from the base plate itself melted the solder before incinerating the plastic housing.

He welded the base of the magnets to the plate that is hold directly to the crane with a hook. Look again.

Naturally, the instructions are a bit specific to the Pentair system he has. However, it isn’t as specialized as you might think. The project relies on the connection for a wired “spa-side remote” that most modern pool systems support. The electrical connections for these aren’t quite standard, but they are all very similar, so you have a good chance of reproducing this for your setup assuming you have a connection for one of these wired remotes.

These rules of thumb are referring to the amperage capacity or “ampacity” of the conductor (wire) and are often correct. Sometimes, these general rules lead technicians to believe that if an appliance is rated for 50-amp breaker/fuse maximum overcurrent circuit protector (MOCP), you must use 6-gauge wire and a 50-amp circuit breaker.

We were pretty close to that 40% rule when our controllers started to fail, which is probably why they only started failing after our customers had use the controllers a few times. We were pushing 22 Amps through 40 Amp rated parts. In other words, using a component at half its rating still won’t cover for substandard parts! Our solution was to find a part that was manufactured to spec and also use the component at half its rating and we’ve not had a verified SSR related failure since.

There is a huge difference between heater and electric motor when it comes to inrush current. But anyway haven’t seen 600A contactor for switching on 60A motor.

A lot of times these days, it seems like we hackers are a little like kids in a candy store. With so many cool devices available for pennies at the click of a mouse, it’s temptingly easy to order first and ask questions about quality later. Most of the time that works out just fine, with the main risk of sourcing a dodgy component being a ruined afternoon of hacking when a part fails.

Relay was severely underrated for the application. Also the real moral of the story is that when you use a ten dollar relay, you get ten dollar performance.