is a mep-002 enough to start a/c

[jbk]

trying to figire out if one of ny 002s will be enough to start my daughters a/c unit. the RLA 17.9 seems fine but the LRA is 112.0. i think this is about 2 1/2 tons maybe 3?.

 

[Isaac-1]

Only way to know is to try it, LRA and RLA are often worst case, you could try putting a good clamp meter on it and measure running load and inrush current.

Ike

p.s. how old is the air conditioner unit?

 

[jbk]

maybe a year or 2 old. was kinda shocked by the lra, i have a 4 ton unit 12 years old and the min. is 26 and max amp on it is 46.

 

[Isaac-1]

Most likely it depends on what type of compressor is in the unit, if it is a scroll compressor (very common on newer air conditioner units) it will have lower LRA and therefore lower starting inrush, compared with traditional piston style hermetics. Scroll compressors started showing up in residential air conditioners about 10-15 years ago, and while they are very common today, they are not completely universal yet.

Ike

 

[Speddmon]

I always suggest anybody wanting to start an AC unit with a generator should install a "Hard Start Kit". Get in tough with a GOOD HVAC guy/girl, and have them install the kit. It is nothing more than a start capacitor and a potential relay.

This kit is actually recommended by almost all manufacturers but for cost savings they do not install them from the factory. They was it works is the start capacitor provides extra starting torque for the compressor motor and reduces the time that the inrush or current is seen by the generator/utility. It is the inrush that is going to make the generator not be large enough for the AC, so anything that can be done to reduce the inrush will help you.

 

[steelypip]

My MEP-002A will start one of my heat pumps while the other one is running (in AC mode). It's not happy about it, and I won't be doing it in practice, but it was impressive to see how much surge capacity the little beast could manage.

I don't remember the equivalent tonnage of the units. Upstairs is 1000 SF, downstairs about 1300 and a much bigger unit.

Concur on the hard start capacitor - they make all the difference in marginal situations.

 

[ETN550]

My 802a (5kw Military rating, 1800 rpm) starts my central A/C. After starting I have about 60% showing on the load meter. Not sure how big my A/C unit is but it is 1994 model so not too efficient.

 

[derf]

What size breaker is the A/C on now?

Also, some modern thermostats will delay the starting of the blower motor until the compressor has started. I think older units just start everything at once. Our thermostat will let the blower run for a short time after the compressor shuts down, too.

 

[coyotegray]

I have a 3 ton A/C. My MEP-002a starts it ok but you can tell it's working hard and will run it, the lights, TV's, computers, Fridge and a freezer in the garage at about 80%.

Adding any additional load (Microwave, washer/dryer, etc) is too much.
I can run everything above plus the microwave, washer or dryer with my
MEP-003a... Brings it to about 85%.

In the summertime if the power goes out I use the 10K. It's just the right size.

I think if I was planning on using a MEP-002a with A/C I would follow Speedmon's advise and get a hard start kit installed.

I think I may check with my AC guy and see what one costs anyway. could help prolong the life of the compressor.

ETA - If my AC has a capacitor on it does that constitute a "hard start kit"..?

 

[mistaken1]

My heat pump was new in 2004. The MEP-002A starts and runs it in heating or cooling mode (80% to 100% on the meter depending on what else is on).

 

[Speddmon]

I think if I was planning on using a MEP-002a with A/C I would follow Speedmon's advise and get a hard start kit installed.

I think I may check with my AC guy and see what one costs anyway. could help prolong the life of the compressor.

ETA - If my AC has a capacitor on it does that constitute a "hard start kit"..?

They should be very cheap...installation is another thing. The parts for the one I put on mine cost less than about $30 total. The start cap should only be about $4 or $5. The relay will be the expensive part, maybe $25 or so. And it will most definitely prolong the life of the compressor. High current means heat...motor windings and heat don't go well together.

As I said, most manufacturers recommend them, but do not install them. They are only concerned with getting the compressor to last through the warranty period, and not much longer.


Also, your AC DOES have a capacitor in it, but that one is the "run" capacitor. We are talking about installing a "start" cap.

 

[ETN550]

What size breaker is the A/C on now?

Also, some modern thermostats will delay the starting of the blower motor until the compressor has started. I think older units just start everything at once. Our thermostat will let the blower run for a short time after the compressor shuts down, too.

Right on, Derf. I posted my response above based on a test I did earlier this year when my compressor and blower were started separately. Since then I had my A/C "fixed". They removed the burnt blower time delay relay board and installed a hard relay to get me going. Now the 802A does not start my A/C as both blower and compressor are starting at the same time. Not a big deal for me as I use a 3kw set anyway and run a window unit in one room.