Introduction: Making an Affordable, Digital, Universal Refrigerant Manifold Guage Set!

I love doing air conditioning as a hobby. I used analog manifold sets, a separate one for each type of refrigerant or groups of refrigerant. I saw the fancy full digital sets and I got envious. The prices of these units are approximately 400usd and more. Also what if the fancy manifold got damaged or failed prematurely? Quite an expensive bummer yeah?

Here is how I made my Own universal digital manifold set using robinair digital Gauges, each costing 99usd. Below are the links on for each gauge.

Low Pressure:

High Pressure:

This approach allows me to easily replace a damaged or defective gauge and to use a spare gauge while the replacement is Shipped.

Step 1: Examination of the Robinair Gauges.

Each came with 3 aaa alkaline cells. I hate these cells since they are prone to leaking electrolyte in high heat conditions.

Step 2: Modifying the Robinair.

I wanted a bigger and shared battery pack for both units. This battery pack will be external to allow easy replacement of the batteries. I have spare nimh batteries at 2400mah so I'm sure I will have long storage life and operation time.

I notched an opening on the back of each battery cover and soldered wires to get the needed power into the units. I put a cable tie to prevent pulling out of the wires once the battery cover was secured.

Step 3: Removing the Analog Gauges.

Here is one of my manifold Guages set that I selected to become the universal one. Using a spanner I carefully removed each gauge.

I will keep the old gauges as spares.

Step 4: Installing the Robinair Gauges.

Each robinair has thread seal already applied. Using a spanner I carefully installed each. I put back the hanger hook last.

Step 5: Making the Electrical Connections.

Using a 3 cell aa battery holder, I mounted it on the back of the low pressure gauge protection boot. Next I soldered the respective polarity wires and applied liquid electrical tape. The ON OFF switch on the battery pack will ensure that the battery has zero parasitic drain even when the gauges are soft off.

Powering up the unit by sliding the on switch at the battery pack shows the manifold to be working. The blue EL back light looks cool too!

Step 6: Testing!

Using my car air conditioning service ports, I hooked up my new digital universal manifold gauge set and read the pressures.

For the robinair gauges, to zero the reading prior to refrigerant hook up, the ON button needs to be pressed twice.

Once I work on different refrigerant systems, I will of course purge the manifold and hoses to prevent cross contamination!

I'm very proud of the work done on the creation of my new manifold. I even made a protective puch for it in this instructable.