Hard start capacitors

[Methodical]

I had a new system installed in July 2013. The system consist of the following:

Carrier Infinity® 17 Central Air Conditioner (24ANB7)
Carrier Infinity® 98 Gas Furnace (59MN7)

I had an annual inspection the other day and the tech suggested I install a hard start capacitor. I understand that it's suppose to help the compressor, but is needed for such a new unit?

I have a few questions for the pros here.

Hard Start Capacitor:

1. What is a hard start capacitor?
2. What is the benefit of a hard start capacitor?
3. When is it necessary to install a hard start capacitor?
4. How does it do it's job?
5. Which hard start capacitor would you suggest for my unit? (searched manual and found no suggestion for one)

Thanks...Al

 

[yeldogt]

Most of the high end systems still come with them ... I'm surprised an Infinity does not have one. They reduce the draw (amp) on the motor -- it lowers the temp of the start coil.

I would see if you can get a wiring diagram for your unit -- many basic systems actually show the start cap as an option. These are different then the normal capacitors they you unit will already have.

With an Infinity -- I would not add anything before doing some research.

I always used the 521 .. I think that is what it was called ... they are less then $50.00

 

[Basskiller]

Did you post this on the hvac talk forum?

http://hvac-talk.com/vbb/showthread...-really-needed&highlight=hard+start+capacitor

 

[Methodical]

Most of the high end systems still come with them ... I'm surprised an Infinity does not have one. They reduce the draw (amp) on the motor -- it lowers the temp of the start coil.

I would see if you can get a wiring diagram for your unit -- many basic systems actually show the start cap as an option. These are different then the normal capacitors they you unit will already have.

With an Infinity -- I would not add anything before doing some research.

I always used the 521 .. I think that is what it was called ... they are less then $50.00

I agree about the research with Infinity. That's why I asked which unit is best for this system. Trying to see if anyone out there have installed one on their Infinity or have installed them on Infinity.

I looked in the install manual, but did not see anything. I will go through it again. Maybe I missed it.

Thanks...Al

 

[yeldogt]

Often you see what people call the "hard start" circled as an option on the wiring diagram located inside the compressor service door.

It is not going to be in the regular manual given to the homeowner.

My gut tells me the unit has what it requires -- I have one and never thought to look. Personally, I would leave it alone.

Maybe I will go take a look at the panel the next time I am at that house.

If I see it as an option in the wiring diagram then maybe -- but with all the electronics -- I would leave it alone without further sleuthing.

 

[Methodical]

Often you see what people call the "hard start" circled as an option on the wiring diagram located inside the compressor service door.

It is not going to be in the regular manual given to the homeowner.

My gut tells me the unit has what it requires -- I have one and never thought to look. Personally, I would leave it alone.

Maybe I will go take a look at the panel the next time I am at that house.

If I see it as an option in the wiring diagram then maybe -- but with all the electronics -- I would leave it alone without further sleuthing.

Thanks. I will take a look and see what it shows.

Al

 

[EOC_Jason]

It's an extra capacitor and relay setup to give some extra UMPH to the compressor when it starts up. Some units have them, others don't, just depends on the design.

It's not uncommon to install them on older units if they lockup, but it's kind of a band-aid solution at that point.

 

[bazar01]

On older txv systems, it takes time for the system pressure to equalize due to absence of balancing line on the txv. If the high side pressure is still high and has not balanced out, the compressor has to overcome this high discharge line pressure and this is where the hard start kit helps. I noticed on newer txv with a balancing line that bleeds pressure to low side. I hardly see a hard start kit. Just my observation. Please correct me if iam wrong.

 

[Methodical]

I decided to install the 521 Hard Start kit, to help prolong the life of the motor since it's an easy install and the kit is not costly.

Thanks...Al

 

[exmaxima1]

It's an extra capacitor and relay setup to give some extra UMPH to the compressor when it starts up. Some units have them, others don't, just depends on the design.

It's not uncommon to install them on older units if they lockup, but it's kind of a band-aid solution at that point.

My 1 year old Kenmore refrigerator was having a problem with the compressor tripping the overload. An HVAC friend of mine said to add the cap and it solved the problem. When I sold the frig 13 years later it still worked perfectly.

BTW, I don't think all applications need separate relays. My cap was just a 2 wire affair similar to this: http://www.zoro.com/i/G2910451/

 

[EOC_Jason]

BTW, I don't think all applications need separate relays. My cap was just a 2 wire affair similar to this: http://www.zoro.com/i/G2910451/

That kit has a built-in relay in the top half.

As for the other person about pressure's equalizing. Another solution that is often done is to put a 5-min time-delay relay in line with the low-voltage. This prevents a person from turning the compressor on & off & on in a rapid succession and lets the pressures equalize. You just have to let the homeowner know about it, otherwise they call thinking their AC isn't working right.

 

[LS6 Tommy]

If you're going to install a start cap/hard start kit, you might want to look into a delay on break relay to eliminate any short cycling that can cause hard starts.

Tommy

 

[bazar01]

That is right.

New digital thermostats though have a 3-5 minute compressor protection feature already that should take care of this. Usually 5 minutes is enough to equalize lo and high side pressures for fixed piston metering device and txv with a bleed hole.

 

[exmaxima1]

That kit has a built-in relay in the top half.

"Separate" vs Built-In

 

[Methodical]

That is right.

New digital thermostats though have a 3-5 minute compressor protection feature already that should take care of this. Usually 5 minutes is enough to equalize lo and high side pressures for fixed piston metering device and txv with a bleed hole.

That kit has a built-in relay in the top half.

As for the other person about pressure's equalizing. Another solution that is often done is to put a 5-min time-delay relay in line with the low-voltage. This prevents a person from turning the compressor on & off & on in a rapid succession and lets the pressures equalize. You just have to let the homeowner know about it, otherwise they call thinking their AC isn't working right.

If you're going to install a start cap/hard start kit, you might want to look into a delay on break relay to eliminate any short cycling that can cause hard starts.

Tommy

The thermostat is the Infinity wifi version and there is a timed delay from when you turn the system off and on and off - 5-10 minutes, plus it runs through some system checks. To the poster that said the company better tell the client about this delay. You are correct because they will get plenty calls about a non working system if they are not aware. I figured out the delay from the old system we had.

Thanks...Al

 

[arsco]

add the hard start kit if you can, from the MFG. other wise use a 521. They will always be helpful new or old