I would call a third company. They should actually try find the leak, not just sell you a new system.
What brand is your A/C system (Lennox, Carrier, Trane, etc)? Find the local HVAC company that is an authorized dealer for that brand. They will be most familiar with your system.
Once you find out where the leak is, you can make an informed decision from there.
Common techniques an HVAC company would use to check for a leak:
- Spray soapy water on the fittings and look for bubbles.
- Use an Electronic Nose to "sniff" around all the fittings (it can smell the refrigerant).
- Add a UV dye to the coolant, let the system run for a week or 2, then go over the system with a UV light (if you see the dye, there's your leak).
(Expect to pay for the leak testing. It can take a good hour or two to go over the whole system, and time is money.)
Once the leak is found, the HVAC company should be able to give you an estimate for the repair. If the leak is something simple like a fitting on a coolant line, the repair can be cheap/easy.
If the leak is in the coils or the compressor, expect the bill to be steep ($thousands). At that point, I would think about replacing the system.
Reasons to consider replacing:
- You fix this leak, but what else is going to go in the system? If the system has been running for a while without enough coolant, there is increased wear and tear on the compressor.
- R-22 systems will be getting progressively more and more expensive to service.
- Newer systems are way more efficient, so expect a lower electric bill. You should be able to calculate the "pay back" period of the new system (how many years of reduced electric bills will it take to offset the cost of the new unit).
- Check for Tax Credits and Rebates. The Energy Star Tax Credit expired at the end of 2011. However, you might be able to get a tax credit on your state or local taxes. Also check with your power company. My power company had a rebate of ~$300 for a high-efficiency AC.
- Newer features on the new system (variable speed fan, quieter scroll compressor, touch screen programmable thermostat, etc).
If both your central air handling fan and outdoor compressor are running and your not seeing any sort of cooling after a 10-20 minutes than I'd venture a guess and say it's time to call an AC repair service.
I'm curious what you are pushing in that makes the compressor turn on? Are you somehow bridging the main capacitor? Capacitors tend to be a common point of failure on AC units and can actually be changed fairly easily. Here is a pretty good article detailing the steps to do so.
To be honest though I'd guess that the bigger problem is the fact that you can get it running and it still isn't putting out cold air. The whole situation sounds like it's low on coolant (have you had it filled in the last few years?). AC's usually have a low coolant pressure switch that will keep the unit from running to prevent damage to the compressor when there isn't enough pressure.
Call an AC service out, many will diagnose your problem free of charge and be able to give you a much better idea of your problem. Be warned though, if your system is old and uses R-22 prices have shot up in the last year.
Best Answer
If the unit is starting and not make your lights go out or dim I would not change it. All contactors have have some evediance of arcing after a short time again since the cap is good and it is starting it really is fine. Last if someone wants to change out the outside unit and continue using the inside unit RUN AWAY! I have seen two many times where someone tried to save a few bucks and the new unit failed in 3 to 5 years, I would only do this if the old refrigrant uses the same type as the new poe or pag oil is what modern units used very old ones used mineral oil. So I agree if it is not broke don't fix it you have a functional unit, companys do free inspections to drum up business in my area and I think it is a scam.