Potterton Puma 100(E) low pressure problem

[Ollie_joe]

Am having a recurring problem with the pressure on my Puma 100 (e) boiler. It has happened on three occasions in the last week. The pressure seems to drop over night and I awake in the morning to a cold flat and no hot water.

I top the pressure up to rectify the problem but am slighly concerned that it has become a recurring issue and wanted to know whether:

This could be a pre-cursor to a much larger problem?
Is there a fault within the boiler and deos a part need replacing?
Or is this to be expected every once in a while?

any help would be much appreciated....

 

[John506]

Bit more info on your system?

 

[Ollie_joe]

It has recently had the PCB replaced and about a year ago the wax diverter valve was also replaced.
It was only serviced last month after the I had replaced the PCB.
I topped up the pressure last night to about 1.5 on the dial and still had enough pressure this morning. Unfortunatle i did not think to take a reading of the pressure before i left the flat.

I did come across a post yesterday regarding the "pressure switch" but not sure if this refers to my problem...?

 

[twgas]

pressure dropping over night is very often due to expansion vessel having lost its charge, tape a plastic bag over discharge pipe outside and check in the morning to see if its full.