Watch out for those inexpensive pressure gauges for A/C refill / check...

[e9999]

I have refilled my 134 A/C system a couple of times with a disposable can. Trivially easy. Have an inexpensive little refill system for that. Just a hose and gauge. All of $30.

I do have a Professional grade refill 3 hose system too. That one has good pressure gauges on it. So I checked the gauge on the inexpensive system with the good one. Lo and behold, the cheapo one was reading 40 psi when the good one was reading 32. So one would probably undercharge the system by 6-8 psi (out of 21 - 36 specs) with the cheapo one, a not so insignificant difference. But on the safe side. I have yet another cheap gauge just like that, that one is 3 psi off.

So, watch out for these inexpensive gauges... I'll still use mine cuz it's so convenient but I'll adjust for the difference.


(FWIW, I have seen the big manifold + 2 gauges + 2 valves + 3 hoses system at HF, with quick connects on both hi and lo sides, for something like $50 on sale. Very inexpensive for what it is. Not sure if you can connect to a small disposable can, though. And don't know how good those gauges would be either...)

 

[-Spike-]

VautoZone loans a decent guage setup for free. Also a good vacuum pump and whatever else you might need. As with most rentals, I always check out the equipment before I leave the store for missing parts and often find some. The price is right, though.
You have to put down a CC or cash deposit for the price of the tool, $100 for the guages and $200 for the pump IIRC. If you decide not to return them, you own them.

-Spike

 

[e9999]

dang, on top of the inaccurate gauge, the cheapo ID EZchill gizmo broke when I put the can on it and I lost most of the 134... There goes another $15. It did work for 4 or 5 recharges until now but still, piece of junk... Stay away...

 

[wxm]

The HF gauge should work, all you need is a tap valve like this one. I haven't done any comparison about their accuracy. But I did tried it last time. It seems ok.

 

[e9999]

The HF gauge should work, all you need is a tap valve like this one. I haven't done any comparison about their accuracy. But I did tried it last time. It seems ok.

I have a can tap similar to that. Unfortunately, the male outlet does not fit my Yellow Jacket hoses which seem to be set up for a conical male connector. Also, using the full manifold set means you got to deal with the long hoses, not so great for recharging oil off a small can.

 

[wxm]

I have a can tap similar to that. Unfortunately, the male outlet does not fit my Yellow Jacket hoses which seem to be set up for a conical male connector. Also, using the full manifold set means you got to deal with the long hoses, not so great for recharging oil off a small can.

The one linked fits right on with HF set. I had a Robinair gauge set, went to HF shopping for quick connectors. But ended with the HF gauge set, easier anyway.

I have been fortunate enough that have not had need to refill oil, but can't see way it wouldn't work.

 

[e9999]

looks like that can tap has a 1/2" ACME male fitting. My Yellow Jacket (and my old Robinair too IIRC) have what I think is 1/4" FFL (not sure). Is it possible that your HF gauge set has ACME fittings cuz it's made specifically for cars whereas mine are for general A/C work? There are of course adapters between ACME and FL but I don't have one.

The issue with oil potentially I think is that on a gauge set the hoses are pretty long and yet it might be good to have the oil flow downhill into the port so that could be cumbersome. Maybe one could avoid that possible issue by holding the can upside down right away so the higher pressure in the can pushes the oil out even uphill. You'll also end up having the set full of oil.

 

[wxm]

I bought mine from sears. I am pretty sure it was 1/4 on the male side also, at least I don't recall I had to use any conversion fitting, though I has been a while. I will double check after I am back home.

 

[wxm]

Just checked the tap vale that I got from sears. It is 1/4 on the male side and it fits HF gauge set without needs of additional fittings.

[edited] correction: the male side of the tap valve is 1/2 (not 1/4).

 

[e9999]

Just checked the tap vale that I got from sears. It is 1/4 on the male side and it fits HF gauge set without needs of additional fittings.

thanks for checking. Odd. The pic shown suggests it's an ACME thread, not a MFL. Doesn't look flanged. Are you sure it's not a 1/2" ACME?

Just looked at the HF pic here:
http://www.harborfreight.com/a-c-manifold-gauge-set-92649.html
it does look like the line has a straight end, not a cone. So seems to me like it's not the standard MFL/FFL connector. Which explains why it would connect directly to the can tap with an ACME end.

 

[rustybucket]

When you say "refilled my system a few times" in what time duration did you refill your ac system? If its less then a year, or mabey two, you have a really bad leak or, you never replaced the seals designed for the r-134a system. The molecules of the R-134A are smaller then R-12 and will pass more easily though the R-12 seals. Best to find the leak and repair it or replace the seals.

I have refilled my 134 A/C system a couple of times with a disposable can. Trivially easy. Have an inexpensive little refill system for that. Just a hose and gauge. All of $30.

I do have a Professional grade refill 3 hose system too. That one has good pressure gauges on it. So I checked the gauge on the inexpensive system with the good one. Lo and behold, the cheapo one was reading 40 psi when the good one was reading 32. So one would probably undercharge the system by 6-8 psi (out of 21 - 36 specs) with the cheapo one, a not so insignificant difference. But on the safe side. I have yet another cheap gauge just like that, that one is 3 psi off.

So, watch out for these inexpensive gauges... I'll still use mine cuz it's so convenient but I'll adjust for the difference.


(FWIW, I have seen the big manifold + 2 gauges + 2 valves + 3 hoses system at HF, with quick connects on both hi and lo sides, for something like $50 on sale. Very inexpensive for what it is. Not sure if you can connect to a small disposable can, though. And don't know how good those gauges would be either...)

 

[wxm]

thanks for checking. Odd. The pic shown suggests it's an ACME thread, not a MFL. Doesn't look flanged. Are you sure it's not a 1/2" ACME?

You are absolutely correct. The male end of the valve is 1/2 (not 1/4), and so is the HF hose connector. Sorry that I might have confused you. I am losing my mind.