Should you hook up your gauges every time?

It’s common practice for many HVAC technicians to hook up their refrigerant hoses every time they evaluate a system. At Baggett Heating and Cooling, we believe the professional technician should determine that action based on the conditions of the call and the need. Here’s why…

Baggett gauges image

Manifold gauges allow a technician to enter the (normally closed) refrigerant system and collect information about how the system is operating.  We can then know pressures, temperatures, and measurements called superheat and subcooling that indicate where problems exist. Notice I said “enter the system” this is an invasive procedure, if you will, and opens the system.

The gauges are attached to the system through what’s called a service valve, much like the valve stem on a bicycle tire.  Each time gauges attach, at least two things happen:

  1. Wear and tear on the Schrader core at the service valve – can and will cause a leak with repeated use
  2. A little bit of refrigerant is lost

Should we connect gauges at every call?


The technician needs to use their knowledge of the system to determine the best practices to perform the necessary service. If the system is and has been operating normally and we are there for routine maintenance, we will take other non-invasive technical readings.  If all of those indicate a properly running system, we will not connect gauges.  Saving your system from unnecessary harm.

Opening a system unnecessarily can cause:

  • Schrader core leaks (after repeated use)
  • Small, but repeated, losses of refrigerant – will be significant over time
  • Possible introduction of contaminants – moisture and refrigerant from gauges from previous calls (even with preventative measures)
  • Shorten equipment life

The use of refrigerant manifold gauges should indicate a professional and knowledgeable technician, but unfortunately, the reverse may be more true.  Gauges may simply be smoke and mirrors just to convince you of their professional status.  

Remember Baggett Heating & Cooling has served the Clarksville/Montgomery County area for over 40 years. Contact us by phone, text, or email.