Hi, What makes you think you don’t have a water leak causing your pump short cycle? ......might be somewhere you can’t see it (unfortunately).
Since you changed the pump out you may have temporarily fixed the leak for 24 hours......which might imply it is near the pump somewhere close to the work that was done. So a seal or not tightened coupling on either side of the pump .....or close to work area perhaps? If it is short cycling the new pump now every 30 seconds.....it is probably a very small/slow leak.
Lets treat this like an electrical problem......isolate the fault by splitting the line. So I would suggest capping the high pressure side of the pump and see if your short cycling stops. If it stops you know the low pressure side of the pump is fine (fresh water tank, water filter, pex lines and couplings). If it still short cycles then the leak/problem is on the low pressure side of the pump......or the pump pressure switch itself. I would expect a new reputable manufactured water pump would be fine though.
__________________
|