Why did they install a "Hard Start Kit"

[avflyguy]

Background....

System outside is a Carrier 2.5 Ton recip compressor about 6 years old. The coil Inside WAS a very old Honeywell 2.0 Ton slab type .
**Yeah I know, mismatch in compressor and coil size. ... that is why it was fixed.

So, the old coil had a leak, so the techs installed a new Trane 2.5 ton "A" coil with TXV in it's place. VERY noticeable difference in cooling capacity.

But then, about an hour after they left, the compressor kicked off and would not come back on. The condensor fan and air handler fans both kep running running.

Called the contractor about it. He said they needed to come back an install a "hard start kit" to the compressor.

When I called he didn't even hesitate as to that being what was wrong.

Says it was because of new "A" coil was so much more efficient, but connected to a 6 yr old 12 SEER comp/cond unit, because of a TXV on the new coil, that was the reason I needed this so-called hard start coil.
They also took off the dryer/filter on the suction side and put a similar looking one on the liquid line. Not sure why?

Can someone explain why I needed this device added? Actually it says on the side of this thing, "Super Boost". It was connected in parallel to the capacitor. What does this thing do and why do I need it?

Last time this happened, before the coil replacement the service guy added some R-22 freon and went on his way. Now with new coil, they assure me the pressures are 100% right on the money, but something about this TXV thing.

Comments appreciated.

[dougvhvac]

Possibly the new coil/txv is non-bleed, meaning freon pressures equalize very slowly after unit shuts off. The result is that the compressor on restart then faces a bigger job in overcoming residual pressure.. a few years ago we had to retrofit a slew of hard start kits to new machines when non-bleed txv's became the norm (helps with efficiency). Other factors could come into play, but you mentioned txv.

[Kevin O'Neill]

The indoor TXV requires a hard start on a recip compressor.

So they put in the Trane coil, now ayou still have a mismatch to the Carrier outside.

I hope they did not charge extra for the hard start. By the way, I would have preferred to put a true hard start on, Carrier has a kit for that. But some suppliers don't carry them so maybe that is why they used the "Superboost".

[bmathews]

It's not a huge deal. But why didn't they match up a Carrier coil to the condenser? Trane makes a better coil in terms of leaking. Carrier is a little cheaper as well.

[beenthere]

TXVs increase the amount of torque required to start compressor.
The hard start kit increases the starting torque of the compressor.
That was the proper thing to do.
The filter in the vapor line should have been removed a few days after it was installed, and one installed in the liquid line as they did. That was proper.

The indoor coil should be a match to the outdoor unit. That is not always easy. Shouldn't be a trane indoor to a Carrier outdoor. Not 100% proper, but it will cool.

[cmajerus]

Carrier is a little cheaper as well.

depends who's buying it, a non Carrier dealer will pay more for the coil than a dealer would in most cases.

[smittyii]

i don't under stand. you have a hodge-podge system that you are obviously just trying to keep running, but you want to know why the tech is doing all this to keep it running? if you bought a new system i could see why you are questioning your tech. don't forget this guy at Christmas time, i know he won't forget you!

[cmajerus]

sounds like this company did good, the guy who installed the Carrier condenser should have put in a new coil from the start. Due to the suction line drier installed would guess that old coil took out the compressor once already?

[catmanacman]

It's not a huge deal. But why didn't they match up a Carrier coil to the condenser? Trane makes a better coil in terms of leaking. Carrier is a little cheaper as well.

it is probably a all aluminum trane coil so it should not leak

[dj3901783]

Super boost = 2 wire "hard start" = more problems than if they put in a 3 wire system. The hard start is a start capacitor with a relay. There's a million units that have TXV's and no hard start. If a unit didnt originally come with a start capacitor and you have to add one to get the unit working it normally means that you only have a limited time left on your compressor until it craps out. That would be my major question as another post said did they charge you for this hard start... a compressor wouldnt start if the run capacitor was low or no longer had any capacity to hold a charge, so for him to say oh yeah put a hard start in it over the phone doesn't make me feel all warm and fuzzy LOL... good luck

[southerncomfort]

2 wire superboost start assists are crap

[beenthere]

Super boost = 2 wire "hard start" = more problems than if they put in a 3 wire system. The hard start is a start capacitor with a relay. There's a million units that have TXV's and no hard start. If a unit didnt originally come with a start capacitor and you have to add one to get the unit working it normally means that you only have a limited time left on your compressor until it craps out.

Kickstart hard starts have a potential relay built into them.

Recip compressors need start kits when they have to start against a non bleed TXV.
Doesn't mean the compressor is on limited time.

[southerncomfort]

We use a true start assists at my work place Beenthere
You outta see some of our installations because they are ultra perfect
I run a static pressure test on every system i work on and document it somewhere on the unit
I will upload some pics later