Recommend A/C Manifold Gauge Set

[Colt Hero]

Recommend A/C Manifold Gauge Set

Which A/C Manifold Gauge Set would you recommend for a non-mechanic? 

Harbor Freight has a $40 set which claims to be accurate to within 2%.  AutoZone has a set of apparently similar quality but cheaper-looking gauges (Quest) for $60, and O'Reilly's has a set by Interdynamics (good gauges, seemingly similar quality) for $90.

I've also located a few units by MasterCool that can run upwards of $160, but I don't know if they're really any better because I don't know what features really matter.

Will the Harbor Freight unit suffice, or will it be too inaccurate (or maybe even leak on me)? 

[billr]

As a DIYer, I ended up getting the Harbor Freight gauges.  I was very impressed with the quality.  They are mostly all-metal, with quality quick-connect chucks for the high/low ports.  The dials are 2-1/2" diameter, so fairly easy to read.  I can't be sure of the real accuracy, as I don't have a lab-grade gauge to check them against; but that's usually true of any instrument you buy, whether it be a gauge, volt-meter, torque-wrench, etc.  As to leaks, I last had mine on an A/C system over a month ago, and there is still pressure trapped in the gauges; so the fittings and valves can't leak very much!

[Colt Hero]

Thanks.  I asked someone here that I know who does HVAC work on the side and he told me to buy the Harbor Freight set.  He also has a YellowJacket set (better quality?), but he said he's used the Harbor Freight set - and like you said - thought the quality was pretty good. 

I'm willing to buy a better-quality set ($150 or so), but I'd like to have someone more experienced give me a good reason why.  But maybe for the DIYer who isn't going to be using these gauges a lot, there really isn't a good reason...

[Colt Hero]

On another forum, someone who's opinion I trust panned the Harbor Freight set saying his set had bad connectors and the gauge stuck on him.  He said he'd be buying a "good set", to which I responded:

But what's a 'good set'? For example:

1.) Is brass better than aluminum? Most units seem to be aluminum, but I ran across a brass set from MasterCool which also happens to have metal valve handles (pointed sideways). It's model # MSC84772G and it runs around $130 delivered. Seems like a good set, but MasterCool makes more expensive sets that look like the Harbor Freight set with an aluminum body and plastic thumbwheels.

2.) It would seem to me that the quality of the valves is very important, but how do you know what quality of valves the unit has? I've seen reference to "double-O-Ring", but that's not the valve, per-se.

4.) 2.5" gauges seem to be a 'must have' for easier readability, but while size matters, how do you know the level of quality of the gauges? Harbor Freight's gauges LOOK good, and they claim to be within +/- 2% accuracy, but are they? Is there a company that supplies quality gauges for the manufacturers of these sets?

5.) Some units say they can be 'recalibrated' in the field. Does this mean the lower-end units cannot be?

Shopping online, at least, it's difficult - if not impossible - to differentiate quality among these different vendors and models. The writeups just don't seem to tell you very much about the product. You end up looking at the price and the picture and that's about it. Even comparing within a vendor (like MasterCool) is a nightmare, as they have MULTIPLE models with seemingly identical features (but a wide span in pricing).

Yes - (almost?) all Harbor Freight stuff is from China - and I hate that, but what I hate more is buying something based solely on price without having a good feeling that the higher price is justified by higher quality. I don't mind paying more, but I want to feel good about the quality that I'm paying the premium for. I don't want to pay upwards of $200 for a "NAME" brand set, only to discover that the quality is really no better than the Harbor Freight set.

[Jim Davis]

http://www.ackits.com/c/RefrigerantGaugeSets/Refrigerant+Gauge+Sets+-+Mastercool.html

[Colt Hero]

Looks like the same story there.  You can get a "professional" Mastercool for peanuts, or you can pay over $200 for a "professional" set. 

Here's one I found that gives some decent info (and looks like a "good set"):

http://www.professionalequipment.com/imperial-service-manifold-gauge-hose-set-631ckp/hvac-manifolds/

It's UL-compliant, for whatever that's worth.  It has 4 valves, and is usable for R-134a and R404A (heat pumps?).

Here's another thing that's unclear to me: some of these units say "2-way, 3-way, 4-way".  Does that mean the number of refrigerants they can read, the number of valves they have, or something else?

[Colt Hero]

Picked one up on rental from Autozone for $99 - and guess what? - it's a Mastercool.  Looks to be model #MSC-89772.  It doesn't have any markings on it anywhere, but the plastic case UPC number shows the "89772", so I guess that's what it is (looks like it on the web).  It sells for about $115 delivered.  However, the writeups don't show the plastic case or mention anything about a free 3-in-1 valve (#85530) that are clearly mentioned for models #89660 (or 89661, which superceded -660).  Those units can be had for $100 delivered, and may actually be the better deal.

I've got a question, though:

I read the PDF manual for the Harbor Freight unit online and it mentions what sounds like a 2nd set of valves on the hose couplings (where you connect to the service ports on the car).  They say to turn the thumbwheels clockwise to close (on the manifold), but then they also say to turn these 2nd set of valves counterclockwise to close before connecting to the service ports on the car.  Unless I'm missing something, I don't see this feature on this MasterCool.  The couplings have ball bearings and a collar that you can spin around and around, but it doesn't appear to do anything.  Do some units not have these secondary valves?  And if so, do I just quickly jam these couplings down on the service port in the car?  Won't there be some leakage as I do this?  Seems like there should be a valve where the service port connection is made, and maybe this kit is missing those pieces?

[billr]

Those high/low port couplers are similar to common shop-air couplers; pull back on the ring/sleeve and push the coupler over the port, then release the ring to lock.  Yes, the Harbor Freight unit does have separate valves right down there at the port couplers, to minimize leakage.  That's why mine still has pressure trapped in it (the gauge set) long after it was removed from the car.

[Colt Hero]

Thanks for that verification.  That's why I went looking online for this model - to see if it was missing those pieces.  Didn't want to return it and have the clerk say I stole them.  I DID notice he watched my hands very closely as I was inspecting the contents for any pre-existing damage.

One other question (this will be the last one):

With the can of refrigerant - there is a brass valve in this kit for that.  Do I back the needle inside the valve away from the can and then attach it to the can (then turn the valve to puncture it), or do I leave the needle fully outward and screw it onto the can (allowing it to puncture the can as I attach it)?  Seems to me it should be the former (so that there is no leakage as the valve is being attached to the can), but it seems to me I've read somewhere someone saying "now turn the valve to release the pin and allow the refrigerant to flow..." (meaning you puncture the can as you attach the valve).   

[billr]

I install onto the can with the pin retracted; like you say, there would be some leakage otherwise.  If I don't use all the can, then I screw that pin back in, hoping to seal the can; but I also leave the can attached to the gauge set.  NOTE:  The Harbor Freight set does  not come with that can adapter, but does have the hose.  I got the can adapter for about $8 as a separate item at another store; but many cans "kits" come with an adapter.  Don't bother with a gauge at the can, the gauge manifold set has what you need.

[Colt Hero]

Thanks.  I wasn't sure if it really mattered which way you did it (except for the possibility of some leakage in one case) but I wanted to make sure that puncturing AFTER screwing the valve on the can wasn't going to create any unforseen problems.

Hmmm... I'll probably use BOTH 12oz cans I bought (with the UV detector) between the two cars, but I COULD end up with some left over inside a possible 3rd can.  That makes me wonder if I should buy my own valve for the can (hopefully - with a cap for the hose line after removing it), so I can save the residual.