Thursday, February 18, 2016

Gauge Manifolds are Obsolete

Gauge manifolds are quickly becoming obsolete. There are now at least four alternatives that allow you to check system pressures and temperatures without connecting a manifold set. Why is this important? Every time you connect a set of manifold gauges, you lose refrigerant. A standard ¼” hose holds around 1/3 of an ounce per foot when filled with liquid. That means a six foot hose will hold around 2 ounces when connected to a liquid line. So assuming the system was charged perfectly when you arrived, after connecting your manifold gauges, it is now under charged.

So how are you going to check systems pressures, superheat, and subcooling without connecting a gauge manifold? You connect a gauge, just not a gauge manifold. Sporlan, Appion, Yellow Jacket, and Testo all make small digital gauges designed to connect directly to the system with no intermediate hoses. These all lose far less refrigerant than even one foot of hose. They also all offer ways of checking the suction and liquid line temperatures. Typically through wireless clamp-on temperature probes. They all offer Bluetooth connectivity, allowing software to calculate superheat and subcooling, perform data logging, and system analysis. Since the software is downloaded to your phone or tablet, updates for new refrigerants are no problem.

One caveat – except for the Appion gauges, they all require a phone or tablet to display their readings. The Appion gauges do have their own digital display, but the others all rely on the portable display you carry around with you all the time.

What about evacuation and charging? The Yellow Jacket Mantooth has a port built in for that, the others will all require an adapter – such as a valve core tool. However, if you are pulling vacuums and your time means anything, you should have valve core tools anyway. You can connect a valve core tool to the system, connect the digital gauge to the side port, and charge through the back port on the valve core tool.

How does all this make gauge manifolds obsolete?
First, you don’t need a manifold to check system pressures and temperatures, in fact, it is better to use the small direct connect gauges for that.

Second, you don’t need a gauge manifold to pull a vacuum: two valve core tools, two large bore hoses, a vacuum gauge, and a vacuum pump with at least two hose connections are what you need for that.

Finally, you don’t need a gauge manifold to charge a system. One valve core tool, two short digital gauges, two temperature clamps, and one hose will allow you to charge a system while checking both pressures, the superheat, and the subcooling. What you will also need is a phone, tablet, or laptop that is rugged enough to be used day I and day out and can be easily recharged.  

1 comment:

  1. This needs to be reprinted in the RSES Journal. Good stuff.