Author Topic: Copper tubing! (Read 21804 times)

280plus · « **Reply #50 on:** July 03, 2009, 06:53:46 PM »

FYI, this biz is TOUGH on the body and it don't get any easier as you get older.

Jim147 · « **Reply #51 on:** July 03, 2009, 07:08:35 PM »

Quote from: 280plus on July 03, 2009, 06:53:46 PM

FYI, this biz is TOUGH on the body and it don't get any easier as you get older.

I left the machine shop after two blown discs and a torn shoulder. I moved to a lighter job.

I was more the refrigeration expert. I like working on the smaller units much more.
When they moved me to management for the second time, working longer hours for less pay, my back just couldn't take anymore sitting in a chair. And my mind just couldn't take anything anymore.

jim

280plus · « **Reply #52 on:** July 03, 2009, 07:17:28 PM »

yea, I've done a lot of refrigeration but got tired of being responsible for other people's product. Plus nobody wants to replace anything so all the stuff I was working on was 20+ years old and people would call MY abilities into question when I couldn't keep their old POS running anymore. Today I'm almost strictly HVAC but I did just work on a walk in beer cooler. Beer I don't mind. It won't spoil or melt.

Brad Johnson · « **Reply #53 on:** July 03, 2009, 07:27:45 PM »

But it does take a lot of quality control testing. Just to be sure and stuff...

Brad

280plus · « **Reply #54 on:** July 03, 2009, 07:40:27 PM »

Excellent point. I used to do a lot of Ice cream freezers and ice cream machines. That required careful quality control as well. I have the waistline to prove it!

Nick1911 · « **Reply #55 on:** July 03, 2009, 09:18:58 PM »

Got everything soldered in.

Applied vacuum.

Fixed vacuum leak at compression fitting from lineset to a coil.

Applied vacuum.

Noted high pressure side valve was sucking some air in. No biggie, schrader valves probably don't work well with vacuum.

Vacuum held perfectly at -1 bar for over an hour.

Applied more vacuum.

Charged system with R22 substitute. (As I don't have certification to get R22. R22 substitute is a hydrocarbon. MSDS looks mighty like propane. Attributes surprising similar to R22.)

Removed high side from gauge set.

Discovered high side valve still leaked.

Reconnected high side to gauge set.

Pondered for a bit. Killed a beer.

Removed low side from gauge set.

DISCOVERED LOW SIDE DIDN'T HAVE A VALVE CORE!!!

Reconnected low side.

Swore.

Went to auto parts store. Bought valve cores and valve core tool.

Removed high side from gauge set.

Tightened high side valve core. Leak stopped.

Removed low side from gauge set.

Launched TWO valve cores like little missiles being propelled by 100 psi refrigerant.

Got low side valve core in.

Reconnected gauge set.

Discovered I lost half my refrigerant.

Put in rest of refrigerant I had.

Current system pressures:

40 / 160 psig.

Ambient outdoor temperature: 78
Liquid line temp leaving condenser: 84 degrees
Air leaving condenser: 92 degrees
Suction line temp leaving evaporator: 77 degrees
Evaporator temp (At bottom): 21

(Icing observed)
Evaporator temp (At top): 73

Sooo.... Looks like I need some R22 or equivalent. I considered using BBQ grade propane

but it's probably got far too much other crap in it.

Thoughts?

Ron · « **Reply #56 on:** July 03, 2009, 09:41:34 PM »

What replacement gas are you using?

The pressures mean nothing if we can't check a PT chart.

If the replacement gas is a blend it is possible that by blowing out vapor you changed the characteristics of the refrigerant. Does the cylinder warn you to charge with liquid only? It is probably OK but inquiring minds want to know.

The propane component is tiny in the blends. Don't try and make your own refrigerant.

Signed,
Ron the former commercial refrigeration tech

280plus · « **Reply #57 on:** July 03, 2009, 10:09:31 PM »

Yup, you need some gas. R-22 should be ~ 70/250 on a day like that. you need to get the suction at least 60 before icing will stop. 58 psi R-22 = ~ 32*F. Another rule of thumb is take outdoor temp, add 30* and convert it to pressure, which you can do right on your discharge gauge. That gives you an approximate discharge pressure to shoot for. Sorry I can't find my T/P charts up here. I'll get them out of the truck in the morning.

Ron · « **Reply #58 on:** July 03, 2009, 10:21:14 PM »

here is a PT chart for NU-22

http://www.icorinternational.com/images/7_UPT.pdf

Nick1911 · « **Reply #59 on:** July 03, 2009, 10:50:09 PM »

Quote from: Ron on July 03, 2009, 09:41:34 PM

What replacement gas are you using?

The pressures mean nothing if we can't check a PT chart.

Excellent point.

It's ES-22a.

Here is a TP chart. [Link]

Jim147 · « **Reply #60 on:** July 03, 2009, 11:09:16 PM »

Quote

Launched TWO valve cores like little missiles being propelled by 100 psi refrigerant.

If you would have turned on the compressor they wouldn't have flown near as far.

jim

280plus · « **Reply #61 on:** July 04, 2009, 08:11:37 AM »

What's with all the fancy R-22s? I'm still buying regular old green can r-22. Haven't run into this new stuff. Jim's link is coming up blank for me but the ES link chart shows it being not quite as cold t to p as the old stuff? Is it a blend?

280plus · « **Reply #62 on:** July 04, 2009, 08:20:22 AM »

Ohhhh, propane? Flammable gas under pressure and electricity in close proximity to each other? I'm not diggin' it.

Nick1911 · « **Reply #63 on:** July 04, 2009, 11:04:58 AM »

Quote from: 280plus on July 04, 2009, 08:11:37 AM

What's with all the fancy R-22s? I'm still buying regular old green can r-22. Haven't run into this new stuff. Jim's link is coming up blank for me but the ES link chart shows it being not quite as cold t to p as the old stuff? Is it a blend?

I would have used straight up R-22, since that's what the equipment is designed for. However, I don't have my 608 cert, so no one can legally sell it to me.

Quote from: 280plus on July 04, 2009, 08:20:22 AM

Ohhhh, propane? Flammable gas under pressure and electricity in close proximity to each other? I'm not diggin' it.

The flammability is concerning.

I'll work on getting my cert so I can avoid doing this in the future.

Ron · « **Reply #64 on:** July 04, 2009, 11:39:55 AM »

Refrigerants with propane as a component in their blend have actually been around for a long time.

The one I linked to is 3% propane. They are safe.

280plus · « **Reply #65 on:** July 04, 2009, 11:45:00 AM »

Cool on only 3%, Makes me feel a bit better. Propane in refrigerant, must be a Texas thing?

Jim147 · « **Reply #66 on:** July 04, 2009, 01:41:29 PM »

I don't know if you've had much time to look into your certification yet but I was cleaning out my office this morning and found my old book and the envelope it came in.

AHAM-NARDA
10 East 22 St.
Lombard, IL 60148
705-953-8956

Things may have changed since then but I just called and they mailed it to me.

jim

Nick1911 · « **Reply #67 on:** July 04, 2009, 08:12:55 PM »

Interesting info, I'll look into that, Jim.

Going off my numbers from yesterday, I calculated:

57* superheat
11* subcooling

From my reading online, this is about on par with a very low refrigeration charge.

I'd have to be concerned about the metering device if the subcooling and superheat were high - right?

Thanks guys!

Jim147 · « **Reply #68 on:** July 04, 2009, 08:51:37 PM »

Quote

I'd have to be concerned about the metering device if the subcooling and superheat were high - right?

To put it in the easiest terms I can think. If the cap tubes were clogged, your high side would be very high and your low side very low.
The small Fedders units used to be a pita on the cap tubes. I haven't seen or heard of much problem with the larger units.

I should have asked earlier. Is this your main home unit?
If it is let me know. If you don't have it working by the time it gets really hot I may be able to run by or call in a favor if you need something else.
It's not hot right now. This is what I call humuggity. When the relative humidity matches the temp it makes for some sweaty working.

jim
jim

Stand_watie · « **Reply #69 on:** July 05, 2009, 01:34:58 AM »

Jim, a little, but not too far off topic. Saw a profile of a successful businessman in current Reader's Digest of a plumber who made a tool for cutting copper or steel tubing. Might be worth buying if cutting tubing is a pain for you...

http://www.amazon.com/dp/B000NUVQ7S/ref=asc_df_B000NUVQ7S842930?smid=A12QCB28TZ2MIN&tag=dealt15623-20&linkCode=asn

Jim147 · « **Reply #70 on:** July 05, 2009, 10:16:30 AM »

Nick, ignore my cap tube comment from last night. I was kind of tired and thinking of something else. No need to confuse you at this point.

Stand, the pain with replacing the cap tubes is removing all of them, forming new ones out of straight tiny tubing, and then soldering them all back in. But I'll take more look at the tool when I get a chance.

jim

280plus · « **Reply #71 on:** July 05, 2009, 10:23:15 AM »

Jim,

it's an 18v cordless band saw. Nice but my sawzall works just as well.

Nick1911 · « **Reply #72 on:** July 05, 2009, 01:09:10 PM »

I just used an average plumbing variety tubing cutter.

I suppose if space was tight, I would use a coping saw with a fine toothed blade. I'd think that would make a real mess of the tube, though.

280plus · « **Reply #73 on:** July 05, 2009, 01:12:11 PM »

Yea, that's when you get all the chips in there. I rarely saw pipe unless I have no other choice.

Jim147 · « **Reply #74 on:** July 05, 2009, 05:31:05 PM »

My mini is only 2"x1 1/4" fully open. It will get into most any refrigerator line.
Then a few regular size cutters. And then if I'm doing something I shouldn't I have a cutter that is over a foot long.

For the little tubes I just score the outside with a small file and snap it off. If you don't cut all the way nothing gets in.

jim

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Author Topic: Copper tubing! (Read 21804 times)