On Sunday, August 28, 2016 at 1:54:39 AM UTC-4, Diesel wrote:
Thu, 09 Jun 2016 14:41:39 GMT in alt.home.repair, wrote:
On Wed, 8 Jun 2016 19:09:57 -0700 (PDT),
wrote:
Hello, I have a Rheem heat pump, model Rpnl-043jaz. The lights in
my house all flicker every time it goes on....Will the hard start
kit resolve this problem?
A hard start might actually make that worse. It does just what it
implies. It adds an extra capacitor to the motor to kick it harder
on the start. This is used when the compressor is getting old and
will not kick over reliably on it's own.
A slight flickering is normal on central hvac startup, depending on
the size of the unit and the panel amperage rating. If the unit is
equipped with a hard start pack, it may not cause any
flickering/dimming effect when powered up.
If it doesn't have this hard start pack though, it could cause the
flicker/dimming without anything actually being 'wrong' with the OPs
electrical system.
On a dead stop, the motor is pulling more amps than it would during a
run phase; a considerable amount more, actually. The additional (but
temporary) request for more amps is causing the temporary flickering
or dimming effect. A hard start kit if properly installed and of
sufficient size for the compressor it's going to be used with, should
reduce if not outright eliminate the dimming effect because it's
taking some of the load stress off the power source. Atleast, that's
been my experience and that of others I know who do hvac
professionally for a living. --- I'm not hvac, I'm electrical/IT.
I'm confused about why you wrote that installing a hard start could
make it worse? I would think the opposite would occur. It's reducing
the load being placed on the panel by the compressor when it's used.
http://preview.tinyurl.com/gpb5dhk
http://www.achrnews.com/articles/119...ard-start-kits
It's the same concept as placing a cap into your cars electrical
system so that the amplifier you just had to have won't seriously dim
your headlights and/or stallout the car when a bass note of
sufficient strength hits at a decent volume.
Agree with your other points, but not this one. When you put a cap
in a DC circuit on the power input to an amplifier, it does act as
a reservoir. It's fully charged during light or normal loads, when
the amp has a sudden increase in power needed, that cap can supply
some of it and being close to the destination, it can do so without
the impedance effects of many feet of wire.
However, I don't think a hard start kit works that way. If it did,
it could only be effective for 1/120 of a second, because that's
all the initial charge that's there prior to starting will last.
After that the AC voltage has reversed, the cap is drained, there
is no reserervoir and it's being charged in the opposite direction.
Current is needed through the AC supply to go into the cap and to
supply the motor which is trying to start. So, unless the motor
gets over it's starting difficulty in 1/120 of a second, I don't
see how the cap can be helping by being a reservoir like it is in
a DC circuit. I think the hard start kit probably works by
creating more phase shift to the start winding, which will go on
as long as the cap is in the circuit.
If your connections are solid from the utility, it may just
indicate that your service conductors are too long or too small.
It may also indicate nothing. As, like I said before, the initial
power required for starting an electric motor from a dead stop is
several amps more than it's going to pull once it's up and going.
Considering that the compressor motor is actually pushing a fluid/gas
around with resistance to the process, it's going to pull a
considerable amount of amps to get rolling.
https://www.amazon.ca/SUPCO-SPP6-Sta.../dp/B0002YTLFE
The comment:
4 of 4 people found the following review helpful
5.0 out of 5 stars Easy install & Can hear the different with the A/C
performance May 15 2014
By K K - Published on Amazon.com
Verified Purchase
My street has only 2 electrical transformers and 15 new houses have
been put in the past 2-3 yrs so the power coming into the house does
vary a bit depending on load on the central lines.
When the A/C used to kick on, the lights in the house dimmed and the
A/C unit took 3-6 secs to be running at full speed. Since installing
this, the lights don't dim when it kicks on and the A/C unit is
running at speed in 2-3 secs. The sound of the A/C unit is now
constant with no humming/buzzing anymore. Unit is just over one yr
old on my one yr townhouse.
The reason I shared that comment about a hard start kit is because
that has also been my experience when I've installed them on a few
machines, to reduce 'flicker' effect. I've never seen one make the
situation worse as they don't cause MORE of a power drain on startup,
they eliminate some of it.
Agree. Best evidence of this is that they are often installed when
the motor has started blowing fuses. That's what happened with my
old AC. Once the kit was put in, no more blown fuses for 15 more
years until it was replaced, while still working. If it increased
the demand instead of moderating it, you'd have blown fuses, tripped
breakers, and they wouldn't work.