charge chest freezer

I'd ask over on the HVAC forum, but I got my head bit off last time.
We have a 21 cuft commercial chest freezer. Quit working. My neighbor
was over last night and put on a pierce style fill fitting and put in a couple oz R134a. Got -27 deg F this morning. So, all unit needs is a bit of refrigerant.
Pressure reading on low side is -15 in HG. Any educated guess on what low side pressure i should fill to?
Second question, my neigbor said R134a is a blended refrigerant so you need to have can upside down to put in liquid. This can be a problem slugging a small system. On all my R12 and R22 systems I've just let the compressor suck in vapor off the top. Is it really necessary to have can upside down?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

That part isn't true for 134A. Many manufacturers recommend charging gas rather than liquid, even on systems requiring much less total charge than the capacity of the dispensing container.
He might have confused 'lube cans' containing both refrigerant and compressor oil.
Also, Karl, almost all refrigerators and freezers specify ONLY charging on the high-side, while the compressor is OFF. That often requires warming the can -- up to 120F.
Charges are typically small. An 18cu.ft. combo might take only 6-8oz total charge. If you cannot observe the frosting of the coils, it makes more sense to 'recover' the old charge, and use weigh-charging to get it right.
Lloyd
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 03 Jun 2015 06:05:06 -0500, "Lloyd E. Sponenburgh"

Thanks for the reply. Good to know I can charge conventionally.
I'm sure you're right for new installs. I don't own the equipment to do recover/weigh/recharge.
I now have a system that leaks. Need to check with it running to a set pressure number and see how much add to get back to there on a regular basis.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

??? Why not find the leak, and repair it?
Lloyd
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

This work above my pay grade. If the unit leaks too much, toss it and buy a new one.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wednesday, June 3, 2015 at 7:52:46 AM UTC-4, Karl Townsend wrote:

For $18 and a few minutes' work, you could find your leak and save yourself the trouble of future refills. http://goo.gl/dQnN6s
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 3 Jun 2015 05:08:33 -0700 (PDT), rangerssuck

And for a few more bucks you can put in a sealer and fix the leak (better than 50-50 chance of the sealer working - but don't expect to discharge and recharge in the future - it's a "last ditch" attempt. If it doesn't last, you ditch it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@snyder.on.ca fired this volley in

Don't expect the 'goo' sealers to positively affect capillary-tube systems. They tend to seal up those parts, too.
I'm not a 'scrounge', generally, but when folks up and down my road throw out reefers or window ACs, I will generally pick them up and dismantle for parts -- just to have them around for family or near-neighbors' problems. It costs me nothing but the trouble to 're-dispose' of the same junk the next day.
A mile-up neighbor tossed an 18 cu.ft. Whirlpool reefer (about 6 yr old) yesterday. I trailered it to the barn, and today had to go back hat in hand, and offer it back to her -- working. 'Seems she'd gotten ripped- off by an unscrupulous repair outfit who sold her a new one because "the compressor was fried" in this one.
Well... it was... but not so badly that simply replacing the run cap didn't fix it up fine. $8.58 + $4.50 s/h for a new one, delivered tomorrow. In the meanwhile, the 'scrap' replacement cap is running it just fine. (that's what the salvaged parts are FOR! <G>)
I hate it when folks get taken like that. The lady was nice, told me "thanks", and said to keep it. So now daughter gets a nice clean working fridge about twice the size of her little apartment job. A $13 replacement fridge in really nice condition with all the toys. <shrug>
Lloyd
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 03 Jun 2015 20:51:49 -0400, snipped-for-privacy@snyder.on.ca wrote:

Those usually don't work -after- all the magic coolant has leaked out.

That's (usually) only good if the compressor hasn't been damaged by loss of coolant and oil, when you catch it on the way down rather than after it's blowing warm. But it's a chance. When mine truly goes TU (I replaced the start/run cap a few years ago), I'll replace it with whatever system + new refrigerant they use. Mine's an old R22 system and will have to be completely swapped out. ChaCHING!
--
It takes as much energy to wish as to plan.
--Eleanor Roosevelt
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wednesday, June 3, 2015 at 10:32:09 PM UTC-4, Larry Jaques wrote:

I'm no expert, but I think you can just add NU22 to an R22 system without swapping out all the hardware or even doing a purge.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 03 Jun 2015 06:52:45 -0500, Karl Townsend

That's the way I figured with my 23 year old A/C system - why bother finding the first leak?
--

Gerry :-)}
London,Canada
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 03 Jun 2015 06:32:22 -0500, Karl Townsend

If it leaks, find the leak and fix it , or replace it. It is ilegal to charge a system without testing it and repairing any leaks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.