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Don’t Forget the Service Wrench
One of my most popular YouTube videos goes over how to adjust TXV superheat. It's a very simple little video that I did at my desk, and the other day I got this comment:
“Good Video but I hate to say this BUT, with the title SCHOOL, why would you show the public an instructional video depicting the use of an adjustable wrench on a valve stem? Service valves, valve stems on TXV's and Acetylene tanks should NEVER be touched with anything but a service wrench… Its hard to unlearn bad habits”
It was a well-deserved rebuke; in my haste, I used an adjustable wrench to show the adjustment of the TXV stem rather than a service wrench.
The refrigeration service is as much a staple of the HVAC/R industry as a gauge manifold. It's really just a square drive ratcheting box wrench, usually with several sizes built-in with 1/4″, 3/16″, 5/16″, and 3/8″ being the most common.
There are many purposes for the refrigeration wrench, including:
- Opening and closing acetylene tanks
- Adjusting TXV superheat
- Opening & closing multiposition service valves to the backseat, front seat, or neutral seat
- Opening typical residential HVAC Service valves using a 3/16″ (liquid line) & 5/16″ (suction line) combo hex key (shown below)
- Adjusting other square refrigeration valve stems
The primary lesson is that whenever you are making an adjustment on a device, tank, etc., you want to use a tool that will do the least amount of harm by damaging the stem edges, as well as use a tool that will apply the correct amount of force without providing enough torque to break anything.
A refrigeration wrench fits the bill in many applications, and in general, getting away from adjustable wrenches is a good idea anyway.