Bosch combi boiler losing pressure

quanto2009

Hi
Got a Bosch combi 28si has been losing pressure checked radiators and pipes for leaks non found, the boiler is maintenance with British Gas called them out and engineer said the top up valve was partially blocked and the expansion tank was leaking and re gassed or pumped up dont know the correct term.
3 weeks later the same thing has happened losing pressure a second engineer said the top valve was partially blocked and tried to sell the wife a Magnabooster filter for £259 no mention of the expansion valve but water has been leaking from the pipe on the outside wall as per the previous visit.

Now are British gas trying to pull a fast one and replace the expansion tank and selling the filter instead anyone with any experience of this appreciated .
Quanto2009

southcoastrgi

if the pressure is below 3 bar when the outside pipe is leaking then the pressure relief valve (prv) isn't closing, you could try to open it up to free any debris but it may need replacing, worchester don't make this an easy job which is prob why you keep getting fobbed off, the last one i did took me three & half hrs, where as if it was located at the front (instead of at the back behind everything) then it could be changed in 10 mins.however you may have a prob with the expansion vessel as well & this could be causing the prv to open.

ps you can buy a 22mm magnaclean for about £90 which of course doesn't include fitting.

quanto2009

The engineer re pressurized the ex vestle and unblocked the pressure valve on the annual service could this be the faulty. no mention of a filter required and said there was no problems with the boiler.
The last engineer about a month after the annual service on his paperwork fitted a PRV and recommended to fit a filter.
Is it worth contacting BG to check this over or will they say I need to get a filter fitted first.

southcoastrgi

typical BG "engineers" & i use that term very loosly, the pressure in the expansion vessel can only be tested by re-leasing the pressure within the boiler (ie draining the boiler) otherwise you will get a false pressure reading, if the expansion vessel won't hold it's pressure this can cause the pressure gauge on the boiler to go up as there is nowhere for the water to expand to causing the prv to open & vent water outside, both the expansion vessel & the prv should be covered under your BG contract, phone them up & say you aren't happy with the two engineers that came out & can they re-visit with a supervisior as you really aren't happy with the service you have recieved.

unclebulgaria

KG is right but also have a look at the pressure gauge when the boiler is on and hot, if it goes right up past 3 and into the red then the expansion vessel is capput, if it stays levelish below 2 and its leaking from outside then the Pressure Relief Valve that was fitted is either blocked or faulty. You can try to give it a quick clearing by operating it quickly to clear sludge.
Like KG says boiler filters arent that dear and a decent heating engineer would fit one for and hours labour plus new treatment.