You have your EPA card, I don't think any supply house will turn you away.

 

I'll check around with some local supply houses when I get the chance. Hopefully you're right.

Around here, you need your card and have an account with them. You'll need a business name, which with several properties you should have. You buy the recovery tank from them, then they exchange them. They won't take a tank that isn't from them. They check by serial number when they don't recognize you. The prices already include rebates so they don't give you anything extra. They will send a bill if the report comes back as mixed refrigerant. I've seen some people get hit with +$1,000-10,000 bills.

You'll need a reclaim machine. Vacuum pump. Welding torch kit. (whichever style you prefer. Silfos or solder) Pipe cutters. Cooper lineset (at least a few feet of each if you're not replacing the whole lineset) sheet metal, sheet metal shears, drill, screws, (if the a coil is in duct board it's different) foil back tape. If you're changing the air handler which you should if you have heat pumps, then it's even more work.

The other option is just fixing the leaks. Since you're doing the work, it'll keep costs down. Buy a half decent refrigerant detector and cal-blue bubble soap, and start looking. If it's in the evap coil, replace the whole thing. If it's in the longest y, just weld a patch on it

Cheers!

$1,000 to $10,000? Yikes! I hope that wasn't for one 30-pound recovery tank. A contractor, especially, never really knows exactly what might be in an unfamiliar system they are recovering from. I wonder if any contractors have tried to make their customers responsible for the cost in their contracts. I doubt it, since they'd be toast when those reviews got posted on Yelp. :laughing:

With the exception of the more specialized HVAC tools, I already have a lot of the tools I'll need. Here's my shopping list for the big stuff I still need to buy:

• Oxy-acetylene torch kit ($300)
• Robinair RG3 recovery machine ($450)
• Nitrogen tank with regulator and flow meter ($230)
• Two-stage 3-CFM vacuum pump ($150)
• Micron gauge ($150)
• Tubing expander ($85)
• Tubing bender ($100)

I'll probably spend a few hundred more dollars on miscellaneous other tools and supplies. So, I have around $1,500 to $2,000 worth of stuff to buy. It should pay for itself after the first job or two. I'll go ahead and get a combustion analyzer when it comes time to replace furnaces.

I've thought about just fixing leaks, but I think it would be easier for my tenants and me to just replace the equipment. With old, unreliable equipment, I would still have to pay someone else to fix emergency breakdowns when I'm not available. I can replace equipment when my properties are between tenants, and it should be much more reliable than fixing old leaky equipment that will likely develop more leaks quickly.

We have to pay for refrigerant we turn in. We rent the bottle from the supply house and turn them in when full.
Youll need about $5,000-$8,000 worth of tools to get you going, from gauges, vac pumps and reclaim machines, meters, thermometers, micron gauge, and torches to sheet metal tools. Don't forget to pull your permits from your local city/state. Who's doing equipment selection and load calculations?

I just found out that Airgas accepts refrigerants for recycling. They even specifically mention one-time projects on their site, so I might check with them.

If you Google "refrigerant buyback," you can find a number of companies that claim they'll buy used refrigerant and even pay shipping costs. It looks like they tend to want at least 200 pounds per shipment, so I doubt any of them are an option for me. But if you're currently paying to get rid of recovered refrigerant as a contractor, they might be worth looking into.

I believe most of the equipment I'll be replacing is sized appropriately and expect to replace it with the same size. However, I'll definitely be doing Manual J calculations before I replace anything. I don't mind doing the calculations by hand, but I might pick up a copy of Right-J if it gets too tedious.

I'll probably go with all Goodman equipment. It's relatively inexpensive, readily available online, and I've heard a lot of good things about Goodman. For example, I can get a 13-SEER system with a 4-ton condenser, 4-ton evaporator, and an 80% 80,000-BTU furnace for around $2K delivered to my property. It actually kind of amazes me how cheap this equipment is without the markups contractors charge.

Some jurisdictions require permits for work like this, some don't. Here replacing equipment doesn't require it unless the work area exceeds a specific number of workers.

Which stresses the point that you'll need to know the codes. For electrical, refrigeration, building, labour, etc. At least to know where to find them and read over them at least once. We can tell you best practices but probably not with specific local regulations.

Cheers!

I'll be sure to get all the required (and maybe even non-required) permits. I figure the permit fee is worth it for the inspection alone. It's always good to have a second set of eyes look over your work.

I've got copies of all the applicable codes for my area. It'll be kind of a fun game to see if I can follow them faithfully enough to pass the inspection on the first try. :thumbup:

 

Around here, you need your card and have an account with them. You'll need a business name, which with several properties you should have. You buy the recovery tank from them, then they exchange them. They won't take a tank that isn't from them. They check by serial number when they don't recognize you. The prices already include rebates so they don't give you anything extra. They will send a bill if the report comes back as mixed refrigerant. I've seen some people get hit with +$1,000-10,000 bills.

You'll need a reclaim machine. Vacuum pump. Welding torch kit. (whichever style you prefer. Silfos or solder) Pipe cutters. Cooper lineset (at least a few feet of each if you're not replacing the whole lineset) sheet metal, sheet metal shears, drill, screws, (if the a coil is in duct board it's different) foil back tape. If you're changing the air handler which you should if you have heat pumps, then it's even more work.

The other option is just fixing the leaks. Since you're doing the work, it'll keep costs down. Buy a half decent refrigerant detector and cal-blue bubble soap, and start looking. If it's in the evap coil, replace the whole thing. If it's in the longest y, just weld a patch on it

Cheers!

 

We have to pay for refrigerant we turn in. We rent the bottle from the supply house and turn them in when full.
Youll need about $5,000-$8,000 worth of tools to get you going, from gauges, vac pumps and reclaim machines, meters, thermometers, micron gauge, and torches to sheet metal tools. Don't forget to pull your permits from your local city/state. Who's doing equipment selection and load calculations?

 

Some jurisdictions require permits for work like this, some don't. Here replacing equipment doesn't require it unless the work area exceeds a specific number of workers.

Which stresses the point that you'll need to know the codes. For electrical, refrigeration, building, labour, etc. At least to know where to find them and read over them at least once. We can tell you best practices but probably not with specific local regulations.

Cheers!

 

You forgot a manifolds/gauges set. You can get away with a cheaper set, no need for fancy digital ones for diy. However some have micron gauges built in, so that save a separate tool.

You'll also need a weight scale so you don't over fill the recovery tank. The total capacity - 20% will be stamped on the handle. Many recovery cylinders are 45lbs, but double check. If you live in a warmer state, then stay under that capacity. You wouldn't want a relief opening in your vehicle.

You mentioned nitrogen "flow"gauge. You need a "pressure"regulator, but the flow can be adjusted with the regulator or manifold set. I've heard of some nasty stories of compressor pressure shells failing when using a flow meter. They didn't survive.

Other then that, you're on the right track

Cheers!

 

I have a couple of cheap analog manifold gauge sets I've never used. I think I gave $25 for one and $50 for the other. The more expensive one is suitable for R410A pressures. I figured it would be good to have a separate gauge set for R22 and R410A since Bourdon tube gauges tend to be more accurate near the center of their scales and the oils are incompatible. I know the tiny bit of oil cross contamination from a gauge set probably won't matter, but it can't hurt to avoid it anyway.

I was tempted to buy a digital manifold with a built-in micron gauge, but I can't really justify spending several hundred extra bucks for something I don't need. Besides, I kind of like having my gauges, thermometers (thermocouple meter), and micron gauge separate anyway. If one tool breaks or gets lost, I can replace it alone instead of buying a new $500 manifold.

Being a consummate cheapskate, I'll probably just use a digital postage scale I already have for weighing refrigerant. It reads up to 110 pounds at a resolution of 0.1 ounce, which is probably about as good as any refrigerant scale. I'm sure the purpose-built refrigerant scales are much more rugged than my postage scale, but the postage scale should hold up to my occasional use.

 

All closed pressure vessels/systems have physical overpressure protection of one kind or another...... even AC's in cars. It's the law in Canada.... and I'm pretty sure the USA too.

 

Other then the internal relief valve in the compressor, most builder/economy grades don't have any over pressure protection external to the compressor. Systems that have a compressor without an internal relief, are required to have an external relief.

 

They do, on the receiver there is a fusible plug or rupture disk or somewhere in the high side. Painted over and small so you don't notice it but it is there somewhere. Would not get UL approval and CSA etc w/o it.

 

Bob Sanders;2353242]No guesswork involved... just proper interpretation of the gauge.

not taking sides here Bob but..

given 1 psi is like what, nearly 52,000 micron and the lowest division on a manifold gauge is 1 or 2 psi I'm wondering how you read the difference between 1000 micron and 500 micron. The gauge simply would not move for that small of a difference.

Right after you prove to me that they can track a burned compressor back to non use of a micron gauge (those were YOUR words)

I suspect it was traced back to the presence of moisture which is being blamed on the (probable) lack of using a micron gauge when vacuuming the unit.

so to those that have done this for a LLLLLOOOOOONNNNNNGGGGGGG time;

when was the micron gauge introduced to the HVAC industry.

 

I suspect it was traced back to the presence of moisture which is being blamed on the (probable) lack of using a micron gauge when vacuuming the unit.

Or... might it be contaminated refrigerant... improper purging of gauges and lines... and a whole host of other "(probables)".... but I'm more interested in exactly how they trace it back to a non use of a micron gauge!?!

 

back to the original question. try calling a HVAC trade school. I Recovered R22.
its cheaper than buying new. I do an acid test on it first.

 

I have not delved deeply into the micron gauge debate as it is getting kinda mind numbing.

At the end of the day if a DIYer is serious about installing his equipment IMO they will read many posts and forums and if only 1 person says you don't need one most people would be suspicous and go with the majority rules concept. I would. They would then get the gauge.

The "debate" IMO is about "proper procedures" when is open to interpretation and micron theory and speculation about whether moisture can damage systems and whether anyone can prove it yadayadayada. Like I said earlier we never used them until the 90's when the manufacturers said we should in the install manuals and the trade leaned in that direction. Same with flowing nitrogen. Nobody I knew even carried it prior to the 90's. In Commercial and pure low temp refridgeration they did but the systems were $50,000 and up. Not some peanuts 2 ton resi system for a couple thousand $$. I know of many 35 yr old non aeroquip systems still running so moisture and debris from no nitrogen flowing during welding did not kill them. The filter drier did it's job. Most die from mechanical failure, wear and tear, power surges and MOST from running low on freon and slugging liquid to the compressor from freezeups.

Reality is one thing, theory is another and has no end to it. To each his own.

 

Seen lots of old systems without air quips that ran 20 plus years, and never had a vacuum pulled on them. they were flushed out by blowing R22 through them. Wonder how many thousands of tons of 22 was blown through those systems, just so they didn't have to pull a vacuum. And save some time. Also seen a large number of those compressor fail at an early age.

Probably also varies with how long, and how harsh the areas cooling season is.

 

So, I'm fairly new at this, but I use a micron gauge every time. What I'm gathering from bob, is that you CAN properly evacuate a system without a micron gauge, but it takes longer.
My question is, even if it takes a half hour more per system, why the hell wouldn't you use a micron gauge if it pays for itself after a few uses?

Ben

 

using a micron gauge has nothing do with being able to properly evacuate a system. It does not alter anything. It is a tool to let you know that you are properly evacuating a system.

if you do not use it, you cannot determine if you have completely and properly evacuated the system but you can speculate that you have. Sometimes you will likely be right; sometimes you will probably be wrong.

 

Got it. I don't like speculating... Plus, my company pays for those tools, and pays me to do the job well every time.

 

Ooookay... I see where the confusion is.

Go back to the other debate thread:

......... My first set of gauges consisted 1/2 inch copper pipe, some 90's, some ball valves, boiler pressure gauges, and an automotive vacuum gauge.

http://www.diychatroom.com/f17/really-bad-day-little-help-brazing-soldering-298810/#post2323626

My new set is digital and can display tenths.

 

I think I'm going to slowly back away from this discussion. It is obvious the two of you are in the middle of something that I don't want anything to do with. You all have a nice night.

 

This whole argument is based on the idea of removing h2o..... H2O by itself will only cause some issues, and at the levels that you'll have at either vacuum, those issues will be minor if at all present. (water droplets not condensing+ fouling of the oil, etc) We should be more concerned about all the contaminates in the system. H2O will break down in the conditions in the compressor anyways. Oxygen is by far a greater concern. Oxidation is a major concern. Throw in some sulfur and carbon, along with the chlorine, carbon, and florine that make up the refrigerant and you'll have some very harmful compounds. (r410 doesn't have chlorine at least)

The lower the vacuum, the less of anything in that system. Manufacturers want less then 500microns for a/c and usually less then 200 for other refrigeration systems. They want it because they grew tired of seeing the effects of these contaminates on the compressor internals when they were returned for inspection. (motor winding breakdown without oxygen causes different effects) A filter/drier will lock up H2O quite effectively, but only before it breaks down. It has no effect on lone oxygen in it's various forms. And that is basic science.

Companies like Copeland and Carlyle will inspect the bigger compressors. Carlyle even pays for the shipping back to them on the bigger +15ton compressors whether it's a warranty claim or not. (It's included in the price of the new compressor) They'll inspect it and deny the warranty if they think there wasn't a sufficient vacuum pulled and it ran like that for a significant portion of the compressor's short life.

Cheers!

 

Understood. Clearly you want as high a vacuum as possible and you would not simply stop at or near the point where the water boils off. I'm not suggesting that at all. But if you know the boiling point of water at a given temperature then it's not hard to see it on the gauge and understand what is happening and what to look for.

 

While you're correct about the characteristics of water, and if you hold a vacuum between 10-20,000 micros, you would know that your don't have liquid water, you'd still have vapor h2o. Either case, a micrometer helps substantially.

Cheers!

 

A residential AC off of ebay costs a few grand and up and has no warranty... a micron gauge is like a hundred bucks. What's $100 for the peace of mind that I didn't have to rely on experience (which I don't have) in order to know when the vacuum was good enough?

For what little it's worth, I thought it was worthwhile to buy one (well, a manifold with one built in) even though I'm only doing one 3 ton 15 SEER unit that cost less than $3k. But I'm a tool geek, I guess, YMMV.

 

Most DIYers who come here are looking for the recommended Professional Industry standard way of doing a install IMO. Not the way we did it on the farm in Malonton MB 50 yrs ago.:laughing: Trying to save a buck at the expense of long term health of the unit is not what they want just a list of recommended tools.

I appreciate the Princess Auto aspect of things Bob but we are not trying to do it as cheap as possible just give general advice. I am sure someone out there will use your method and do it w/o one but hey it is a free world. Blow and go was the industry standard and the real techs used a vacuum pump sans micron gauge in the good ole days. Beer can cold suction line and check the Delta T and away we went. Different strokes for different folks.:yes:

 

Your low vacuum method will be passable for an automotive A/C. But detrimental to a standard residential A/C.



PS: Is your heat pump actually setting on the deck, or is on pump ups/feet.

 

Your low vacuum method will be passable for an automotive A/C. But detrimental to a standard residential A/C.

Well, at least I have gotten that far with you. I'll take it.

PS: Is your heat pump actually setting on the deck, or is on pump ups/feet.

 

ok guys, now that the shooting has slowed, maybe somebody can explain something to me:



I don't care how low the pressure, getting the water to evaporate is meaningless if you don't get it to move out of the system. Creating a vacuum does not create much flow especially after the bulk of the air is removed and especially when you get to that lower than 1000 micron level working down to 500 or lower micron. Just not a lot of "air" movement there. Given you can have lines may feet long, if there is moisture in the form of vapor, how to you get it to travel all that distance to the port so it can be sucked out?


this is what I am talking about:

a vacuum cleaner may create a lot of vacuum such that it can hold a bowling ball but that does not mean it will clean a floor worth a dam. You have to have flow of a great enough volume/velocity to make the dirt get sucked into the bag.

so, once you have the vapor (1o, 20, 30, 40 feet away), how do you get it to migrate to the port where you have the vacuum pump attached?

 

I believe that that is helped by the triple evacuation process that we use.

 

It will naturally flow from a high density zone to a lower density zone. On other words, even with few gas molecules, the pressure (or lack of it) close to the vacuum pump will always have gas (or states of matter) move flowing towards it from the slightly higher pressure at the other end.

This is why on larger systems, I'll put my micrometer furthest away, or if not possible then at least, only on one side of the gauges, while the other side is open to the vacuum pump. Then you're measuring the highest pressure in the system and not the lowest. It will equalize given time after isolating the vacuum pump.

Cheers!

 

true BUT how long does it take for the water vapor to migrate 20-50-100 feet?

and the lower the pressure, the less differential there will be between any two points so there will be less "flow" so again, how long does it take vapor to move 20-50-100 feet?

I mean, if the point is to remove the moisture, vaporizing it isn't, by itself, enough. You have to cause it to be removed from the system as well.

 

There is no such thing as a perfect vacuum (not on earth anyway) and you therefore can't get all the impurities out. You will always leave some water, some nitrogen, or some other impurity in there. As far as water goes, receiver/dryers are used to clean up what a vacuum can't.

 

There is no such thing as a perfect vacuum (not on earth anyway)

Even space, isn't a perfect vacuum.

 

The better the vacuum, the less resistance anything left inside will experience. A micron gauge is a absolute measurement, so it's telling you exactly how many molecules are left in the system. (if you felt so inclined you could actually calculate the number of molecules left, if you know the internal volume) So when you're at your target vacuum at the point furthest away from the vacuum pump, the whole system is considered "clean enough" to keep the requested purity of the refrigerant within tolerances. It takes less time then you'd think for everything to flow and equalise. I've evacuated larger 30, 40, 50 ton systems and the equalization after isolating the vacuum pump is rather quick. Measured in minutes not hours.

Filter driers only catch solids and lock up water. They don't help with oxygen or nitrogen left in the system.

Triple evacs help to ensure that only nitrogen is left in the system compared to a mixture of water, oxygen, sulfur, and everything else that you can imagine in the atmosphere. Since we can't get a perfect vacuum, it's better to have something that causes less issues then something like oxygen that is extremely reactive. (if noble gases were cheaper, and as safe as nitrogen we'd use them instead. It's rather difficult to disrupt the ratio of gases in a room enough to be unsafe when using nitrogen compared to just about anything else)

Cheers!

 

nitrogen.

engineers, the supposed most educated, are the most inexperienced and thus most repair costly folk I ever come behind.

I love taking your thousands of dollars to repair what you guys thought you knew more about than us real world.

A 608 license would have explained where and how to dispose of recovered refrigerant, btw. It did on my epa exam..

 

engineers, the supposed most educated, are the most inexperienced and thus most repair costly folk I ever come behind.

Do you have more specific examples? I ask partly out of hope of hearing an amusing story

It's true that engineers are often inexperienced with real world technical matters when they first graduate engineering school, but many engineers became engineers because they liked technical stuff and tinkering with machines, not because they really liked calculus and thought that if they became engineers they could leverage that into a six figure job.

A 608 license would have explained where and how to dispose of recovered refrigerant, btw. It did on my epa exam..

The questions I've seen about this topic were pretty short on practical details... stuff like tagging cylinders of recovered refrigerant before shipping and not mixing refrigerants, but not answers to practical questions like "will a supply house take a cylinder from anybody with EPA 608 certification, or only from their own accounts?" that the OP seemed to be getting at. (Which is, after all, a question of store policy rather than federal law or safety.)