I have a heat pump water heater, and would like to install permanent pressure gauges on the liquid and suction lines (or more likely have a professional install the gauges). Analog gauges are fine, though i2c would be even better. The unit uses rfc134a, appears to use standard thread, though it's made in Europe.
I suspect I could purchase a manifold like this, and cap the yellow line to prevent accidents:
But I'm concerned that over the lifetime of the system, which is all hard copper pipe, the hoses on the gauge could get brittle and crack. What hard pipe alternatives are there? What sort of threading specifications do I need? What's the best way to get this done?