Bourton - newbie question

We are new to Autosleeper so not sure if a noise I hear when turning a tap on in our new Bourton is normal or not. In addition to the hum from the submersible pump there is a fairly loud clicking type noise coming from the boiler area. It stops when I turn the tap off or a short while afterwards.
I presume this is the pressure adjustment valve I have read about but should it make this noise if it is correctly adjusted. Your help would be much appreciated.

Hi Steve

I would presume the same, but it should be fairly easy to check.

First carefully mark the position of the pressure adjustment valve so if necessary, you can put it back exactly as it was.

Then turn the tap on and twiddle the valve, only by a quarter turn each way, and see if the clicking noise alters. If it does you have probably found the culprit, and a slight adjustment may stop the noise. (Emphasis on "slight" - these valves can be very sensitive.)

To double check that it really is the valve, run the tap and set off the clicking noise, then shove one end of a stick in your ear and put the other end firmly on the pressure valve. If it is the valve clicking you will hear the noise transmitted up the stick. (Old engineers' trick, but they usually use a long screw driver!)

You will be lucky to mark the position of the adjustment valve on a Bourton. The adjustment is reached through the rear hole in a panel that covers some electrical gubbins and water pipes. You can get your hand through the hole but then you won't be able to see the adjuster to mark it. 

Reach down through the hole and directly under it you will find the pressure valve with the adjustment wheel on top. You may have to gently move a few wires aside to actually get to the wheel. Just turn the adjusting wheel slightly anti-clockwise until, hopefully, the chattering stops.

My pressure valve seems to have gone on the blink as I can't get it adjusted properly. I believe that the non-return valve has stopped working as when I switch the pump off I am sure I can hear water flowing back into the fresh water tank.  I have lifted the panel to see whether I could change the valve but everything is so tight under there I just put the panel back. We get cold water out so can use the van but the dealer will have to sort out when it goes in for servicing.