Hi,
Not knowing what brand of pump you are using, but 2 things can cause a loss in pressure. nCheck around the pump itself and see if there is a filter compartment. It will be a little bit of felt like material covering the pumps intake. They can become quite clogged and soiled in time, if this is so make inroads to obtaining some new pads.
Secondly and more seriously as regards to air pressure is the diaphram itself. There should be some little screws on the pump housing, unscrew these. (obviously disconnect the pump from the electricity supply first) You will see a rubber diaphram assembly, check the rubber for any sign of wear & tearand also look to see if it has a hole in it. If thats gone then purchase a new diaphram rubber to fit your make of pump.
I hope this was of some help to you.
Regards
BigC
