5-2-1 Solution, or snake oil?
There is a gadget called "5-2-1 Compressor Saver" which claims to protect your machinery and save electricity:
I sure would like it if some pros would look that over and tell us whether the claims are bogus. My thinking is if there really is a problem, and the solution is that easy, the manufacturers such as Trane are ethically obligated to include it in their products already. Am I off base?
Thanks in advance -- Pstu
its just a start kit...
...they should be put on in some cases, like when the evap coil has a TXV
Hard start kits are rarely included with new equiptment anymore due to scroll compressors and cost considerations. The contractor who installs the system determines if this optional device is needed.
Ethically responsible eh?...Remember when spare tires and rear bumpers were options on new pick up's?
hard start kits are not necessary to make the system start and run. manufactures are woried only about the equipment lasting through the warranty period, with as little money spent to do it as necessary. as a dealer it is up to us to sell the customer on an upgrade by explaining the benefits. as a tech i think every system sold should have a hard start kit installed. 95% of the scroll compressors i have replaced have not had hard start kits installed. 95+ % of the units installed with hard start have never had any issues. 5-2-1 refers to the terminal conections on the potential relay used to switch the capacitor out of the start winding circuit after the compressor is up and running.
5-2-1 is a 3 wire hard start kit. If you need start assist I would choose the 3 wire hard start over the 2 wire booster you parallel into the run cap.
Remember the old line for memorizing how to hook up a start capacitor with potential relay? 5-2-1, Common, Start, Run. Looks to me it's just a start cap with a pot relay and a lot of razzmatazz making it sound like cutting edge technology. Some old tech was showing me how these things work back in the seventies. Nothing new or razzmatazz about it.
"Hard start"...often refers to when a compressor that normally started for years on just a run capacitor now needs additional torque to get it running. This is a sign the compressor is in trouble and may not live long.
"Start assist" is for reciprocating compressors that are on a system with a non-bleed thermostatic expansion valve. They need extra torque to overcome higher pressure sitting on the compressor cylinder head at startup, being that the system does not equalize during the off cycle.
Building Physics Rule #1: Hot flows to cold.
Building Physics Rule #2: Higher air pressure moves toward lower air pressure
Building Physics Rule #3: Higher moisture concentration moves toward lower moisture concentration.
Trane installs a hard start kit on all of their units that come with a recip compressor, and many of the heat pumps that come with scroll compressors.
The 5-2-1 brand start kits look good, but the potential relay can't handle continuous coil voltages in the 400v+ range.
I put 20-25 of them in over the course of a year and had several fail. In all cases where they failed, the voltage between start and run for the compressor was >400v.
The makers of generic start kits REALLY should list, on the package, the continuous coil voltage the relay can handle.
Oh well, I just went back to matching up a potential relay to the operating characteristics of the compressor and building my own stat kits like I always did before.
Maybe some day someone will market a generic start kit that is good for more than just troubleshooting, or getting a compressor running so I can get the readings I need to size a real start kit.
I won't be holding my breath though.
Or "2 s1r 5 c", say it as "2 sir 5 c".
Originally Posted by shophound
Originally Posted by pstu
Ads such as this make people think there is a problem when there isn't.
All straight A/C units would benifit from suction accumilators.
But you won't find them in a/c's.
Capacity limiting devices would help to stop short cycling, you won't find them either.
If all things benifical were added, you would be paying the same for a low end unit as you do now for the higher line units. And the higher end units would go up even more then they are now.
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