F&E tank overflowing intermittently

[Helg]

Have traditionalvented indirect heating system. F&E and large water tank in loft. All worked well until my watersofterner gave up the ghost. While fiddling around with it I shut down bypass valve by accident. Water in house ran out. Got that sorted again. But ever since the F&E tank is overflowing, ever so slightly, maybe two buckets a day. But odd thing is, early morning there is no dripping at all when I check first thing after getting out of bed. The other odd think since the shutdown (half a day or maybe longer, only noticed it when my wife screamed in panic 'there is no water!') is that sometimes there is quite a lot of noise/rumbling from the cold storage tank (guess it refills), just 3-5 minutes, then dead quiet. Had some plumbers tell me there is a fine crack in cylinder pipe but just want to avoid new hw cylinder when it could be something else and much simpler, airbubble for ex) . May also add that hot water is VERY HOT, one of the plumbers said that is a bit odd. Not sure if that is relevant but I mention it. have an old Potterton, 32 yrs, but always told DO NOT REPLACE, new ones are rubbish in comparison. Have tem setting 2.5
thanks

 

[picasso]

Have the boiler stat replaced, are there any controls on the cylinder? I am guessing its on gravity hot water pumped central heating.

 

[durhamplumber]

DO NOT REPLACE, new ones are rubbish in comparison. Have tem setting 2.5
thanks

Don't believe everything you are told.Certainly could be holes in coil

 

[undertrained]

Have you checked the cold water tank that feeds your cylinder? I have seen it where they connect the 2 overflows together.

 

[ianmcd]

I shut down bypass valve by accident. Water in house ran out

What By-pass ????

 

[foxhole]

''old Potterton, 32 yrs, but always told DO NOT REPLACE, new ones are rubbish in comparison.''
Tosh, old boiler like that is costing bundles extra every year due top poor efficiency.
Replaced mine along with extra insulation, gas bill has halved.

 

[Helg]

By-pass on pipes into water softener, so no water went into house at all for a while, until my wife screamed 'There is no water', then opended the by-pass, slowly water returned to all the taps, started opening them from highest one first, lots of bubbling, but they came on one after the other. But since then I have this f&e overflow, ever so slowly, maybe two-three buckets a day, also lots of gurgling noise from the pipe where it leads into the cold water tank, not all the time, but the moment I use water first time in morning, then on and off occasionally, never long, mayb 2-3 mins