Gas Boiler Pressure problem

Wise Old Elf

Please forgive the silly question....

I've a Vokera gas boiler heating water and radiators, a normal setup (I presume), but the water pressure has dropped to zero twice in the last two days. The boiler is the original in the house, so probably about 13-14 years old.

I've topped up the water to bring the pressure back to normal and got the heating going both times, but I noticed that the pressure went very high once the heating was on for any length of time. It's then dropping back to zero pressure once it's off for any length of time. Google suggests it's an expansion vessel issue.

Is this a new boiler job or can these things be fixed, and if so, is it an RGII person I need or a plumber?

Edit to add: I can't see any obvious leaks and all the radiators get hot when the heating is working.

DGOBS

You will find that the safety valve is releasing water when the pressure s getting above 3bar (when hot) and then as the water contracts as it cools is then leaving you with low pressure, this water can be seen usually where the safety valve is piped externally (around, and below there you flue pipe exits usually)

It is an indication that there is an issue with your expansion vessel (part of the boiler if its a Vokera system boiler) it may have failed and need replacing, or it may just need recharging, also when this occurs more often than not, the valve allowing the water out (PRV Valve/Safety Valve) may also need replacing as a lot of times they do not reseat properly.

In any case, your best off to have an RGI out to check and maybe service your appliance.

Wise Old Elf

Thanks a mill, I'll get an RGI body out.
Had a look around the external pipe yesterday evening but the whole area was wet so couldn't tell. Boiler was serviced in September or thereabouts.

DERICKOO

Simple mistake Simple solution
I've also got Vokera gas boiler MYNUTE HE 35 heating water and radiators Boiler was not heating water, Rads OK.Looked at treads ,manuals boiler,no faults shown.scratched my Head well that did not help and then it dawned on me last week i searched the hot press for a flannel sheet in the process i turned the temperature valve down to 30 degrees,turned it back up to 75 grreat hey presto water started heating.This may help someone in distress in the future simple mistake simple solution.

Wise Old Elf

Should've updated this at the time, RGII people came out. It was the expansion vessel. He depressurised it, replaced the safety valve, and all is well since.
I could easily have done the hot press thing as well though