[rankins66]

As the title says, what is the difference between the 2? They appear to do the same thing except the UPRO41 is a push-on start relay. What if the refrigerator has a run capacitor? Is 1 preferred over the other? Is it safe to use either of these long term or just until the correct parts are installed? After reading some of richhappy's comments I guess it's safe to say a 3 in 1 start kit should never be used? How does a person check for correct voltage at the compressor? If there is no power to the compressor does this mean I have a faulty cold control/thermostat or defrost timer? Sorry for all of the questions. Just trying to educate myself a little on how compressor's operate. Any help would be greatly appreciated. Thanks.

[richappy]

If you use either 3n 1 hard start devices in a modern R134A compressor, you will burn open the start winding within a week, or less.
I think the UPRO41 has wires to wire in the run capacitor, but the other one has no wires for that.
For the record, I hope to get a used R134A compressor and a scope at a Ham swap meeting this Saturday and get some pulse test data to confirm this serious problem with pictures!
After completion of data recording, plan to do destructive test to define roughly what rms pulse voltage levels blow out the windings and length of time before windings blow out due to direct 115 volts wiring to the start winding.

[rankins66]

These are both considered hard start devices? Good luck on Saturday.

[richappy]

Both have the same compressor destroying capacitor.

[rankins66]

Thanks again richappy. I'm just trying to find a start device to use on an R-134 type compressor until the factory start device can be installed. Which I prefer. Not to beat this in the ground but are you saying either of these can be used on an R-12 type compressor? Without fear of damage to the compressor? Long term? Thanks again.

[richappy]

Yes they can be used on a R12 compressor, they are impedance protected. Post model # so we can select a start device.

[rankins66]

No particular model. Just looking for a universal start relay to use on customers refrigerators until the factory replacement parts come in. Doesn't Appliance Parts Pros sell both the URO41 and UPRO41? AP4503412 and AP4503418. I guess for the older compressors. What are your thoughts on making a compressor test cord? I need to make one for future use. Again, I appreciate all of your help.

[richappy]

You can use the start device RO41, a universal relay that provides poor overload protection and no thermal protection, so I would replace it as soon as possible. You can also test a compressor with it.

[Noexpert]

[quote=richappy;501675]If you use either 3n 1 hard start devices in a modern R134A compressor, you will burn open the start winding within a week, or less...

I have never heard of any problems with overheating or other damage using 3 n 1 relays - the design virtually makes it impossible. If anything the number one or two reason for using 3 n 1 over OEM parts will be prevention of overheating or fires. It is a little dirty industry secret but start devices are NUMBER ONE reason for all the refrigerator fires in the last 20 years or so.

There are thousands of OEM start devices, still in use, that are responsible for overheating and numerous fires. Millions of those original devices were replaced under various recalls specifically because those devices CAUSED not only overheating but fires. Unfortunately millions more of the same or similar devices are still out there.

The problem is that most consumers never check where the problem is and often just call someone to diagnose and repair the refrigerator. What they get is not what is best for them but what is best for the tech and the manufacturer - people often get the same or similar flimsy and dangerous OEM replacement part (in this case start device) and have the same problems and fires recurring over the lifespan of the refrigerator.

I know that first hand because I had a spectacular fire (shooting sparks, smoke and a heat so powerful it melted all the metal parts and even the pins on the compressor) in my out of warranty, 5-year old Whirlpool ET1WTKXKQ00. The tech showed up and the first thing he wanted to do is simply replace the burned part with the same OEM part - that's a definition of insanity but is done every day in the appliance industry.

At the time I knew there were overheating and fire problems caused by dangerous OEM start devices across industry because of the publicity over recalls from various manufacturers. My Whirlpool ET1WTKXKQ00 at the time was not on the list of recalled appliances but quick Google search showed that there were many complains of kitchen refrigerator fires caused by the start device on that specific model too.

Just keep in mind tha almost all the start devices manufactured by various manufacturers within last 20 years either had the same (flawed) design or were actually the same (just different part numbers per various appliance makers) and those were the NUMBER ONE reason for all the fires started by refrigerators across industry.

In addition to the thousands of documented fires there are many more that the consumer never sees. Normally the fires get attention only if there are people dead as a result - like in that Texas fire - google "Expert: Fridge may have caused day care fire."

Normally it may happen at night or while no one is home - the affected start device melts or goes on fire and then burns itself - there is a weird smell in the house but by the time anyone finds out what happened the start device is already cold either melted completely or just melted inside (with rattling sound and metal pieces falling from it) so most people never even know they had refrigerator on fire.

Anyway, never blindly trust a manufacturer tech or expert - by definition they have to give you answers (and parts) that are the best choice for them or are mandated by the manufacturer. Instead what you always want to do is at least do some research first yourself. It is simple - if you have a refrigerator on fire do a quick Internet search like "refrigerator on fire" and plug your model number - if your appliance is one of those affected there will be numerous entries right there.

Better yet, have the appliance checked by an independent tech that works for your benefit for a change... It is not as easy as it sounds because many techs simply don't know any better and the ones that know actually are still dependent on the establishment one way or another so they tend to push solutions that work best for them, are easiest to implement for them, and last, but not least, make the most economical sense for them, not the consumer.

Noexpert

[richappy]

The packaged start devices with the internal ptc waifer and overload (not a Klixon) will sometimes burn up as they do not provide good thermal and power overload protection. The best devices are the discrete ptc device and a Klixon overload.
I studied the 3 n 1 hard start device and they will provide NO thermal overload protection and very poor power overload protection.
When there is heavy transients and power spikes, the 3 n 1 will supply very high inrush current. As they are used often when the compressor fails to start from damaged start winding, they will often do more damage and in some cases, catch on fire.
You can use these devices, but they will not be recomended on this forum, never.