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The Daring Dufas[_7_]

On 12/9/2011 6:48 AM, wrote:
On Dec 9, 4:35 am, The Daring
wrote:
On 12/9/2011 12:52 AM, Bill wrote:

"Rich Greenberg" wrote in message
I had my A.C./heat pump serviced today. The tech is suggesting adding
something called a "hard start" to the compressor starting circut which
supposedly reduces wear on the motor. And costs almost $200.

I have never heard of this. Have any of you and is it a good idea?

Let's see... The AC manufacturer has electrical engineers designing
their equipment. And this equipment has a "name plate" with a
recommended circuit to power that unit. I should think that would work
if the appropriate circuit and wire gauge is used?

And this person thinks the manufacturer of the AC equipment did not
design things right? And he knows more than that manufacturer? What are
his qualifications?

Might want to ask on alt.engineering.electrical and get an expert
opinion. Or better yet, call the AC manufacturer engineering department
and see what they have to say...

A little clue since one of the legal things I do for money is servicing
HVAC and refrigeration equipment. If you look at the wiring diagram for
most AC condensing units, it's usually inside the cover over the
contactor, you will see information on connections for an optional start
assist device or kit from the manufacturer. Some units are shipped from
the factory with a "hard start kit" or device already installed but most
are not. There is another option not always installed by the factory
called an "anti-short cycle timer" which keeps the compressor from
trying to start under load after shutting down until the system
pressures have equalized. These items along with high and low pressure
cutout switches and condenser fan cycle switches AKA head pressure
controls are usually part of the premium priced units. All the extra
bells and whistles are left off of the less expensive builder or
contractor grade systems. The extra parts are not that expensive but to
a manufacturer building a million systems, ten, twenty or fifty dollars
per system can add up to a great deal of money where the bean counters
are watching every penny of production cost in order to compete with the
next manufacturer. The start assist devices are usually unnecessary
unless the customer's AC unit is in an area where the power supplied by
the utility may fluctuate enough to cause problems for compressors that
are starting under load. An honest service tech recommending a "hard
start" or "kick-start" device is not at all unusual and depends on the
condition and age of the compressor and quality of the utility power.

TDD- Hide quoted text -

- Show quoted text -

I would not put a hard start cap on a unit that was working
fine. If it's tripping the breaker sometimes when trying to
start, then after making sure all else is in order I would put
one on. That's what I did with my old unit when it was 10 years old
and got another 16 years out of it.

I have seen a "Kick Start" device break the connecting rod in a
reciprocating AC compressor before. One of the first items I will
always recommend a customer let me install is an anti-short cycle
timer. The timer prevents the compressor from restarting before
system pressures can equalize allowing the compressor to start under
the least load. The time delay is often one of the things that can
be programmed in most digital thermostats and I always check for it.
If you wonder why it's important it's because whenever the power blinks
or someone plays with a mechanical thermostat, the timer prevents the
compressor from being slammed on and off which really puts a lot of
stress on a compressor both electrically and mechanically.

TDD

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