unequeal heat pump/air handler tonnage

[Howie89]

Background:
Two years ago under a home warranty call my heat pump a Janitrol CPH36-1FB (3 ton?) was replaced with a Payne PH10JA042000 ( 3 ½ ton?) unit. At that time it was recommended that the indoor air handler, a Janitrol/Goodman A36-10 (3 ton) be replaced because the accumulator had a lot of rust. Since it was actually still working, the home warranty company would not allow replacement. Fast forward to a week ago and trying to heat my house the outdoor unit would not work. It would cycle on and off and then eventually it would not even do that. I called in the original company that had put in the new heat pump and they said there was leak and all the Freon was gone and that the air handler needed replaced. I was able to run on emergency heat. Since I no longer have a home warranty service I called around and got quotes based off of the information on the tag on the air handler, a 3 ton unit. Using a new company, I had a new 3 ton Ducane air handler installed. Everything was fine for a few days, then once again the outdoor unit was not running. Called in the new company and they found there was no Freon in the line. They traced it to the reversing valve in the heat pump. The tech said the problem is having a 3 ½ ton heat pump installed with a 3 ton air handler. He said that the original installers of the heat pump should have never have done this and that the heat pump should never be bigger than the air handler, smaller is ok. He also said that if all that I do is fix my heat pump that I will probably have leaks twice a year somewhere in the system. He recommended that I install a new 3 ton system.
My Questions are:
1. Is it true that the heat pump should be equal or less in size than the air handler? If so, is this basic knowledge an HVAC tech should know?
2. If this is such a bad situation how was I able to get along two years with a 20 year old air handler before there was a problem?
3. If I pursue fixing the heat pump as is, can I expect more leaks to occur due to the heat pump size?

Sorry for being long winded, but I wanted to make sure I gave all the background information.

I appreciate any and all help.

[HayZee518]

if the reversing valve is designed for the larger system then there should be no questions. as far as freon leaks, some type of corrosion is happening inside the joints causing them to leak. the joints should have been brazed with silver solder not 50/50. if there's a lot of vibration at the condenser or A coil I would look there first at the joints. normally the freon is a closed system even with a reversing valve. that just reverses the gas/liquid flow. high side pressures are about 325 and low about 70.

[Howie89]

The reversing valve is in the 3 1/2 ton heat pump. The HVAC tech said that he could feel oil under the reversing valve and that is how he "traced" the leak. The system currently does not have any freon in it so the system will not run so I can not check for vibration or pressures. Could there have been something that he did when installing the new air handler and charging the system that would have caused a leak at the reversing valve? I wanted to leave fixing my system to the "pros" but I am getting the impression that all anyone is doing is guessing at parts then replacing. I believed that the air handler needed replaced since it was 25+ years old and looked it, but now I am not so sure what to believe. The tech's suggestions are outpacing my bank account. Is there any way to troubleshoot the leak myself? Can I visually see a difference between a connection with silver and 50/50?

Thanks for the help.

[HayZee518]

silver solder or sil-phos has the appearance of a dull copper at the joints. 50/50 looks silverish just like water pipe joints. brazing the joints requires the heat to get to a dull red glow with the torch before the brazing rod will flow. regular solder melts at a much lower temperature. to effectively charge a system, one must connect up a vacuum pump and pump the system down to 30 inches of mercury for 12 hours. this removes all moisture from the system. valves are shut vacuum pump is shut off and the system is allowed to rest for 24 hrs before ANY charge is introduced into the system. this is to test for leaks. if they don't wait for the 24 hr draw down test, they're looking for trouble if they charge the system. go to a web site that has air conditioning parts and go look at a reversing valve. its solenoid operated and the only moving part is the coil slug and the spool inside.

[Howie89]

Well I know that they did not do the draw down test and wait 24 hours before charging as you describe. When changing the air handler they were in by 8 am and out by noon. What kind of problems could this have caused?

Thanks,

[HayZee518]

hvac

if there were no isolation valves in the system, then a complete draw down would have been necessary. any tech who knows his stuff will use the vacuum pump in his business. sometimes they use a tool which crimps the tubing shut so they can remove a component but after the component is replaced they must use the same tool to bring the tubing back to being round. in my opinion this is a rube goldberg repair - I don't like it! there will be weak spots where the tubing was crimped. I looked at a site and most freon leaks are at the schrader access valves caps. Here's a pix of the reversing valve.

[Howie89]

Thanks for all your help HayZee. Hopefully I can get this problem fixed soon. Will update this thread when I know more.

Thanks again,