Help - no hot water

[neil]

all started with the overflow from the clod water tank in the loft continuosly overflowing, ball valve working fine, but hot water is being forced up the cold feed to the immersion tank. Cold tank in loft gets tepid. In the kitchen and bathroom I can hear water rushing through the pipes. I now have no hot water, as I assume the immersion is filling with cold water. First plumber thought it might be the coil, second thought it wasn,t because water was crystal clear. Heating is fine radiaters get hot etc. When you turn the cold tap on in the bathroom (Mixer tap) cold water trickles out, hot comes out fine (but cold). Third plumber thinks there is a problem underground with the hot and cold crossing somewhere, but I thought only the cold comes in from underground. All this started when I went on holiday in August when i came home to find no water out of hot taps. Plumber said it was an air-lock and used the cold water flow, sending it up the hot pipes etc. It worked, but two weeks later everything else suddenly happened. help.......................

Neil

 

[cjg]

sorry don"T know too much on these indirect systems, but (to me) i would sus air lock some where on hot run, back fill with cold possibility, but as said thats my guess,

 

[fuzzy]

do you get water but its cold out of cold taps?
the problems of cold water would first appear to be a seperate one from the vent discharging into the F&E cisten (Immersion tank?)
Are there non returns on the mixer taps? had any work done recently?

 

[buff]

if the coil had gone in the hot water tank then it would have escaped thru the vent pipe and you would see water entering the cold tank is this the case?
if the cold tank is getting hot/tepid then hot is enetering the tank i cant see it being thru the cold feed

 

[justlead1]

Is it backing up the hot via a cross connection (mixer taps, w/machine, shower mixer or alike)