Terence McCann

You mean a semi-hermetic compressor? A vacuum pump will still not remove compressor oil. With a vacuum pump? EDIT: Changed because I was being an a-hole - as usually.

To expand on this a bit - and I'm not trying to be argumentative. Seeing as oil will not boil at 29.9" of vacuum how does this system remove all the oil? Let's, for a moment, assume that it does. Does it remove all traces from the inside of all surfaces? Does the machine store the oil in a separate container so that it can be measured/weighed out? If you're working on a system, and you've just removed all the oil, you will need to know how much to add back in (assuming that it is a hermetic compressor with no sight glass). I can recall watching a sight glass, for oil level on a semi-hermetic compressor, and seeing it bubble as a vacuum was pulled but this was only refrigerant boiling off from the oil. This is why we shouldn't run recip compressors when it is cold outside. The refrigerant migrates with the oil and will be pumped out - and as we all know you can not compress a liquid - something will break. In my former life we use to work on systems that were 1,000 tons plus. I'm most comfortable in big commercial/industrial equipment rooms. I've designed custom control systems (Barber-Coleman Controls) for oil chillers on gear cutting machines - Horsburg & Scott. Went through trade school from 1977-1979. Did the hands on work till a fall ruptured three disks in the neck. Had spine surgery in 1984 and then went into management for the rest of my HVAC career which consisted of Service Manger, Service Sales, Sales Manager and General Manger. Responsible for a 7 million dollar service department which included supervision of 32 union pipe fitters, 5 union plumbers, GPL as well as a on going 5 year strategic plan. Also worked with the Cleveland School System in the maintenance department - lot's of exposure to fire and water tube boiler systems. I've never felt compelled to post a resume before but, for some strange reason, feel the need now. Having been away from the industry for many a year perhaps the technology has past me by (wouldn't be the first time). I'm always willing to listen. Sorry to go a bit sideways with this thread...

That's for refrigerant, not oil, however I understand your point. The Robinair recovery machines we used had a liquid switch to so that you could tap the liquid line thereby evacuating the system quicker. The point is you wouldn't use a recovery machine to pull a vacuum and a recovery machine, as well as a vacuum pump, does not remove compressor oil. A recovery machine and a vacuum pump are two different animals.

Ok.... If you're converting from a 22 to a 410 system, and don't want any problems, replace everything - condensing unit, line set and evaporator. The only person I would trust to properly clean the system of all traces of the old refrigeration oil would be me. There are as many hack A/C contractors as there are roofing companies. Quick, short, cut corners, get in and get out philosophy prevails. People flock to low bid and you get what you pay for. Marc and I got into a discussion about liquid line dryers a while back and their necessity. To boil it down - you buy a new, pre-charged condensing unit, an evaporator that has a holding charge of nitrogen and an ACR line set that is virgin with a nitrogen holding charge. As you braze the copper you purge with nitrogen to prevent contaminants/flakes. Pull a proper vacuum then test. If everything checks out you open the services valves to let the refrigerant out of the condensing unit. Start, check and adjust charge as need to compensate for length of run. Are liquid line dryers needed? No. Are the necessary? Absolutely. There are a lot of techs that cut corners and/or are not taught properly. So much mis-information out there. Let's stop posting to every post because we like to see our name in lights. Let's post when we are sure that we passing on solid information that our fellow inspectors can pass onto our clients.

Refrigeration oil does not boil at 30" of mercury (however water does). Techs routinely pull this amount vacuum but never have to refill a system with refrigeration oil after the fact. Pulling a "deep vacuum" will NOT remove all traces of refrigeration oil! I've worked on many a system, pulling a 29.9" vacuum and never had to replace compressor oil. We use to drain the oil on large ton systems, using a pump designed to evacuate liquids, but a vacuum pump ain't sucking all the oil out of a system. Having been out of the industry for a number of years though perhaps they have come up with a vacuum pump that is not only used for the evacuation of vapor but will also convert into a liquid pump. Can you point me to a web site that sells such a product? God knows I've been wrong before.

The reason for a "deep" vacuum is to remove moisture as it will boil off. The only way to really cleanse a system is with a refrigerant like R-11 which has cleansing proprieties, like dry cleaning fluid (was also used in large tonnage centrifugals). However was the first on the chopping block due to the Montreal Protocol. A suction line dryer will help clean up a system, like after a motor burn, however it won't clean a R-22 system that will be switched over to R-410a. Also, as Marc has stated, a recovery machine will only remove refrigerant.

More Saving - More Doing

Motor oil.

If you go with a new condensing unit, with 410a, then you'll need a new evap and really should replace the line set as well (although they can be cleaned - follow manufactures guidelines). The air handler/ furnace does not need to be changed. We had a chat about this in the not to distant past.

Ha! Yung looks like she can see just fine but it makes one wonder.

Congrats Mike - puts up with you and is good looking too! I would imagine that you got the better end of the deal [] You ever wonder where thirty years went? Goes by in a flash doesn't it...

The basement looks like a real Phillip too.

Nah... You'd have great plans to build something, and discuss it in depth, but then you'd get hungry, perhaps have a glass of wine or two and then take a nice 3 hour nap. I'm only going on what I've heard though.

The model number 018 (18.000 BTUs) looks like a 1 1/2 ton unit Rob. I agree, looks a tad small for the sf. I use a rough 600 sf per ton rule.

Typically the nipples going into the tank are dielectric.

Good luck with that in a court of law. My inspection agreement holds about as much water.

I've been on the board of our HOA a few times (out of pure selfishness - I care about my money). This isn't a house you're looking at. You are inspecting for the BOD and the BOD represents, and is accountable to, 40 home owners. Obviously it is not impossible but the liability is great and so are the responsibilities. This statement: We'd like to be sure that the building is in good shape before the HOA takes it over from the developers means you're it. E&O insurance paid up? I might tackle something like that but not alone - I'd have a good team around me including lawyers and I wouldn't be bashful about the price. Fools rush in....

What Marc said, shut off your humidifier for a while. Most folks really over humidify their homes. The next thing that comes with that type of moisture is mold growth.

No food but there's 784 channels of TV 24/7.

I've never seen it like that in a bathroom before - wow.

Good eye Darren [:-magnify

They put the 90's in for filter access. B vent in the attic? One other thought... everything looks a little cramped in there, is there enough combustion air? BTW, I like the duck.

Even a major leak will not blow that much oil out. Even though oil tends to migrate throughout the refrigerant lines the majority will stay in the compressor. Good guess though.

Amen. Not sure where but someone, a long time ago, said "write as if you were sitting there talking to them". You don't need to use "big" words or inspector speak. It's broke and it needs to be fixed. Moving on...

Thats the first thing that came to mind. Problem with that is a "mist" of that magnitude would run the unit out of gas within a day or so. At best these units only hold slight amount of refrigerant.