Fluctuation in pressure can be caused by debris in the filter. Start by cleaning and back-flushing your system. Pressure problems can also be caused by seals that are leaking. Check the area around your pump for dripping water, which could indicate a problem with a seal.
First you must locate your filter. Next you must determine if the filter has cracked. If not, it may be that the filter is clogged and causing it to fluctuate.
Make sure your pool is full enough that the skimmers don't suck air. Make sure your basket lid is tight. Open your valve on the filter until water comes out and then watch the pressure. Make sure to bleed all air before turning back on. You probably have air getting into it.
The reason the pressure of the pump fluctuates has to to with the water in the pool as the water rises and falls the pressure will rise and fall accordingly.
there is air in the water in the circulation,which causes change in the presure, also, the pipe and other equipment might have leakage, whicj causes losing pressure.
