another ferroli andother fault?

[mkflow]

hi anyone got any ideas.
ferroil f24 combi pressure drops about 1/2 bar in an 12 hour period.
have check PRV & expansion vessel. Have checked rad - all ok. cant see and visable leak though some pipework does disapear?
anyone got any ideas or have a similar prob? was going to put some leak sealer in system?

[villa_tom]

I'd go with the leak sealer, Its good stuff and only about 12 quid so if it doesn't work then you've not lost out on much.

[gas man]

this boiler has a tendency to eat recuperaters check the condensate connection for water after its been off for several hours,leak sealer wont help

[mkflow]

recuperater?? what is that

[gas man]

hang on its not a condenser? my mistake on a band b boiler the condensing heat exchanger is refereed to as a recuperater so if this was a f24b it would be suspect as they are weak

[mkflow]

ok thanks gas man was bit worried there!
that boiler is still slowly leaking somewhere have put leak sealer in and still dropping

[hills603]

Hi when you say you checked the pressure vessel, did you mean for leaks, or pressure? These have a common fault in that they tend to loose there internal pressure, which leaves no room for expansion, so when the boiler heats up it lets out the excess (expanded) water through the safety valve, then overnight when the water cools down again the pressure drops to below the minimum operating pressure.

If you havent checked it, do the following:

Turn of the two heating flow and return taps underneath the boiler, drain the water from within the boiler, either using the little black philips head drain point next to the right hand heating pipe connection, or loosen the heating pipe connector from the Bottom of the boiler (NOT the copper pipe nut, the nut on the valve elbow that connects to the boiler). Once empty, remove the pipe from the bottom of the expansion vessel, then connect a small car footpump to the presure valve (looks like a car tyre valve with a dust cap on it) on the top of the vessel, it should be 1 bar (14.5 Psi) pressure. If not, pump it up gently to the correct pressure, then reconnect the pipe, close the drain tap, or do up the pipe nut underneath the boiler, open the two isolating valves and top up the system to about 1 - 1.5 bar on the pressure guage.

Run it for a couple of days and see what happens.

The valaves usually fail on the top of the pressure/expansion vessels and slowly leak out the air, like a tyre going falt, so expect the problem to return in a few months. If it does, you'll need a new expansion vessel.

Hope some of that helps,
Andy.