after making some considerable changes to my hydronic radiator system, i wanted to pressure test it. so i used one of those gauges with a tire-like nozzle and a 3/4" female socket.
when i filled it with water, there was no leaks and the pressure read 15 PSI.
then i drained the water and pumped 30 PSI in the system because i was told that it should be tested to about 1.5x the operating pressure and i added 5 PSI to the cold water pressure to provide for thermal expansion, approximating it to be 20, then that times 1.5 is 30.
at 30 PSI, my relief valve was leaking air like crazy through the female threaded socket on its bottom, i was able to reduce the leak some but not much by twisting the control lever on top.
should i concern myself with this if there is no leak with cold water? i understand that hot water in the system will have more pressure although i do have an expansion tank.
also, i was wondering if the relief valve should have a pipe installed in its female socket in the bottom. it is installed right next to the reducing valve after the stop valve out of the main water supply and before the expansion tank.
If the relief valve is supposed to trip at 30 I would do the test at say 27-28 psi (slightly shy of 1.5 times working pressure). Come back the next day and if the pressure has held then the system passes the test.
If the relief valve leaks where it is screwed onto the system (at a joint) then that should be repaired. That is a system defect, not the relief valve in action.
The good conscientious technician or serviceperson will carry extra oils and lubricants in case the new pump did not come with oil or the oil was accidentally spilled, so the service call can be completed without an extra visit.