The HVAC company just did a 6 months “free” service. Everything was great, no recommendations, but the tech said the “office” may call and recommend we install a hard-start kit. I think he said it was about $350. He mentioned it would help the compressor life, especially pulling refrigerant up 3 stories in the heat of the summer when it’s under high pressure.
What’s the pros/cons of a hard-start kit? I see you can buy them on Amazon for about $30. Will it extend compressor life? By how much on average? Is the hard-start kit easy enough to install that I could do it?
We’re going back to NC this weekend and probably won’t go back to the condo until fall or winter, so we got plenty of time to figure this out.
I gotta throw the BS flag on this one.
Liquid refrigerant coming down, vapour going back up.
It doesn’t sound like a hard pull.
But:
I haven’t worked on refrigerated systems for a few decades now.
As I remember, a hard start is only added when a motor has trouble starting.
An example may be a dual rated 230-208 or 230-200 Volt motor installed on a 208 Volt system with chronically low voltage.
In the summer, with most of the ACs in the building running, low voltage may be an issue rather than lifting refrigerant vapour up three floors.
You may benefit from a hard start retrofit, but it will be because of voltage issues, not lifting vapour.
A poor man’s hard start is a second starting capacitor installed in parallel with the original starting cap.
Disclaimer: I have used a second cap to good advantage on capacitor start motors, but I have not used one on a capacitor start motor.
It may be safer to buy the appropriate off the shelf hard start device, the $30 device.
The $350 may be $100 for an hour to the site, $100 for an hour labour to install the device, $100 for an hour back to the shop, (However long it actually takes) and the $50 for $30 unit. Bought wholesale for $25 and marked up to $50.
By the way, the nameplate is for the air handler in the residence, not the condenser unit. The air handle has a 1/8 HP fan.
You will have to go up on the roof to get the nameplate data for the compressor.
My suggestions are subject to correction by anyone with more recent data.
The last refrigerator that I bought doesn’t even have a compressor motor.
It has a linear compressor.
An inverter drives a core attached to a piston back and forth.
When it failed and I attempted to troubleshoot it.
I failed miserably.
I never saw one of those before.
Fortunately the manufacturer offers a reasonable flat rate repair package with an extended warranty on the repairs.
Good luck with your unit.
@WaRoss I thought the same thing. The previous unit had been in service about 15 years with no hard-start kit. The condo complex has had no additional units for 30 years. Most electrical devices have gotten more efficient that last 30 years. So?
Note to self - take multimeter next trip to the condo to check the voltage under load (i.e. a hot day).
after searching “hvac hard start kit”, ya may want to consult with an electrical engr. more amps are needed at startup. Use a meter than can capture peak amps at startup and normal operation will be helpful. recording the amps at startup is more useful. check amps on an annual basis, before and at end of heating season.
the “hard start kit” almost sounds like soft starts for large electrical motors in industrial service.
Some random musing.
Why may you need a hard start?
For refrigeration, mostly to overcome low voltage concerns.
If the voltage is low, the compressor may have trouble starting.
It may stall, it may take a few seconds longer to get up to speed.
Some units start unloaded and as the unit starts pumping and the pressure rises, the load comes on. If these are having trouble starting, they may start to turn and then stall.
If the unit has a Klixon over-current protector, the protector will disconnect the motor until it cools down, UNTIL IT DOESN’T.
With a refrigerator on too low voltage, the Klixon will disconnect the unit until it cools down and then automatically reset. If the voltage remains low, this may repeat until something fails, most likely the compressor.
The current at the beginning and end of the heating cycle may be interesting but it is not of much use.
There may be some relationship between the temperature difference between the condenser temperature and the evaporator temperature.
This is not the ambient temperature although that is related.
This is the actual evaporation temperature and condensing temperature as determined from the respective pressures.
Counter-intuitively, as the pressure and temperature differences increase, the current tends to drop.
I digress.
The peak cooling season, when the voltage tends to be lowest, is when the unit may have trouble starting and may benefit from a hard start kit.
There may not be much correlation between running current and stalling when starting.
You may consider looking for a cheap data logger to monitor the voltage.
With a remote condenser, you may not be aware of the need for a hard start until it’s too late.
It’s late, I,m tired.
I’ll write more in a day or so.
