Harbor Freight AC Gauge Question

[47newcastle]

Hello! I just bought a AC manifold gauge set from HF. When I opened it i noticed that the low side gauge needle was at 1psi not 0. I also noticed that there are caps on the gauge to remove and insert a screwdriver into. I'm guessing this is to adjust the gauge? Is it as easy as turning the screw until it is at 0? I know its just 1 psi but it bugs me. I just wanted to run this buy you guys before I mess up my gauges. The instructions did not say anything about it.

 

[AmickRacing]

Yup, that's what the lil screw is for! All refrigeration gauges will have those zero-adjust screws.

Now, if you want to be reeeeaaaaallly **** about it, technically the gauge should be calibrated around the middle of the working pressure range. Back when I had more time to be ****, I'd bring in a jug of R-22 and leave it in the house for a day or 2. Take the temp of the jug, gauge up to it, use the PT chart, and adjust the gauge so that read accurately, which typically made it a bit off on the low end, but it wasn't much at all. Since I work on fairly large tonnage HVAC units, honestly I don't worry about precision quite as much. Seems like small coolers and freezers are where the precision is needed.

 

[47newcastle]

Thanks! I should be fine then since it was only off by 1. I'm just using it to evacuate and fill ac systems in vehicles.

 

[crewchief888]

one of my co-workers has a HF A/C guage set...

quite possibly the biggest pile of **** i've ever attempted to use.

BOTH couplers leaked first time out of the box...

i finally got them to seal to the QD by clamping them onto the hose..


he returned them, at least the 2nd set only had one coupler that wouldnt seal.

 

[Tim C]

I don't know about the HF gauges, but I've got a cheap set from advance auto for home use. It had the problems with the couplers leaking or not locking on. Mine would unscrew from the hoses so I bought the couplers from the Mac truck they were $45 each and after locking it on you screw it down to engage. The gauges work great now.