Why do AC manifolds hate me?

[leroyd92]

I feel like I'm doing something wrong when it comes to manifold gauges. I've gone through 2 ac pro manifolds in the last 2 years, using them 3 times. Randomly freon stops flowing from the can when trying to fill through the low side port.

I thought it was my crap can tap, bought the one that pokes through the side of the can, everything seemed great when checking my wife's truck last week.

Then today, I got 1 can through the manifold and on the 2nd can, only part went through, ended up doing the rest with a retail ac pro can topper because nothing would go through the manifold set anymore. I'm at a loss. I feel like I'm doing an amateur thing but I don't know what.

Hoses are tight, manifold will show pressure but nothing goes through my sight glass when I have the can tapped

Not sure when I'll need to do freon stuff again. But I'd like to figure this out.

 

[CDX825]

Get a set of yellow jacket manifold gauges. All the ones the parts stores sell are cheap junk.

 

[mk378]

The sight glass is a gimmick feature you don't need it, professional models seldom have one.

If you see the pressure on the low side gauge go up to the can pressure but it isn't flowing into the car, it's likely the coupler is not pushing on the shrader valve in the car enough to open it. This is common on cheap manifolds.

 

[leroyd92]

The sight glass is a gimmick feature you don't need it, professional models seldom have one.

If you see the pressure on the low side gauge go up to the can pressure but it isn't flowing into the car, it's likely the coupler is not pushing on the shrader valve in the car enough to open it. This is common on cheap manifolds.

The blue low side coupler?

 

[wtd]

The blue low side coupler?

Yes, you should only be charging through the low side of the system. High side needs to be closed. Not seeing anything in the sight glass does not necessarily mean that it's not charging. I use Robinair gauges and I usually only see anything in the sight glass when I initially open the low side to begin charging. After that I don't usually see anything.

 

[atikovi]

I thought it was my crap can tap, bought the one that pokes through the side of the can, everything seemed great when checking my wife's truck last week.

Why are you using cans? Not a very accurate way to add freon.

 

[wtd]

Why are you using cans? Not a very accurate way to add freon.

Probably because most DIY'ers don't have a 30 lb tank and refrigerant scale. I ended up buying both because I got tired of trying to charge to capacity with 12 oz cans and side taps. The tank and scale makes it so much easier.

 

[TurboTravis]

You can accurately use the 12 ounce cans with a digital gram scale if you are patient enough. Here is an example-https://www.harborfreight.com/digital-scale-95364.html

 

[wtd]

I have an earlier version of that HF scale and it works to a point but trying to account for the can tap and hoses going to it can be difficult since the weight on the scale changes depending on how the lines are positioned and if they stay in position without tipping the can over.

I used that method for awhile but it was just easier to get a tank scale and tank. After the initial expense, it's worth it to me and recharges are a breeze. Set the scale for how many ounces the system takes and then shut the tank down when the buzzer sounds.