Why does the High pressure gauge vibrate at what appears to be the same frequency as the piston? Details: While charging the system, the High pressure gauge began, very slowly, to vibrate when the pressure reached ~125 psi. As I continued charging, both High/Low pressures continued to rise as expected, and so did the magnitude of the High side vibration (which made it difficult to identify true pressure). All components are new including hoses (except condenser and evaporator). Florence dye mixed with oil. Thoughts/suggestions? John
Assuming you have a valve on the pressure gauge, just throttle it in a bit until the gauge is steady, not too much or you will trap the reading and it will not read true
Sounds like poor or defective gauge set. The gauges (should) have a restrictor that dampens the needle fluctuation. Sometimes they blow out on cheap gauges, where they are usually just a stamped piece of thin brass with a small hole.
Hey Mike 32, I don't have a shutoff valve at the suction or discharge ports on the compressor, and I wish I did. I should have replaced them with some that were. I just took it for a ride and it seems to work fine. Thanks for your thoughts and suggestions. John
Hey Mike996, I like your suggestion. These gauges are very old but are already set up for R12. My other set is brand new but set up for R134a. I should have attempted to convert them so I could have used them instead. I'll do so this weekend and give feedback to the forum. Thank you John
