Primatic cylinder problem

[pugsman0]

Hello and help please.
My header tank has been continually overflowing. After much observation i have discovered that water is flowing back up the pipe that fills the cylinder. It is also warm. How can this happen and can I cure it with your help. I have drained down the complete system rads and all and refilled. Same problem. Started happening about a month ago so now driving me mad

 

[Paul Barker]

I would scrap it (you'll get about £15 to £20) repipe for indirect cylinder, though with copper price rise these are now £170 ish at Screwfix. Obviously you then need a f/e tank and as stated may need to alter pipework.

 

[pugsman0]

Bearing in mind there are no moving parts what can have changed to make it start doing this?

 

[Paul Barker]

corrosion.

 

[croydoncorgi]

Hang on....
This thread says 'Primatic....'.
If so, what 'header tank' - with a Primatic there ain't one!!!

Does OP mean 'cold water storage tank' when he says 'header tank'. If so, no problem. Get rid of the Primatic ASAP and replumb for a proper indirect cylinder.

Otherwise, let's start gain....

 

[Paul Barker]

Yes that's what I assumed he meant.

If other option still want scrappng.

 

[EliteHeat]

Obviously you then need a f/e tank and as stated may need to alter pipework.

If so, what 'header tank' - with a Primatic there ain't one!!!

Does OP mean 'cold water storage tank' when he says 'header tank'. If so, no problem. Get rid of the Primatic ASAP and replumb for a proper indirect cylinder.

Otherwise, let's start gain....

Anyone else confused?

 

[pugsman0]

Cheers guys.
I was hoping to not have to change the cylinder as I can see it ending up with the whole system needing to be changed. And yes it is the water storage tank not a true header tank.
Will it be the inner cylinder that has coroded thus not maintaining the air bubble?

 

[chrishutt]

If the water level in the feed tank is rising there must be higher pressure water entering the system at some point. Most likely culprit is a shower mixer that is connected to the cold mains and tank fed hot and allowing mains pressure water to return up the hot supply pipe. No reason to scrap the cylinder at all.

 

[2face]

it is buggered renew ..

 

[pugsman0]

it is b*****r renew ..

Whats that mean?

 

[pugsman0]

If the water level in the feed tank is rising there must be higher pressure water entering the system at some point. Most likely culprit is a shower mixer that is connected to the cold mains and tank fed hot and allowing mains pressure water to return up the hot supply pipe. No reason to scrap the cylinder at all.

Strange cos thats what I thought at first but defo no mains feed anywhere near the heating / hot water. hot water is rising up the feed pipe so i guess this is the old theory of heat rising. Also it is not enough to cause it to rise through the proper hot water exit / vent pipe.

 

[chrishutt]

No mixer showers or mixer taps?

If it's not mains pressure what else could push the water level up to the overflow level? Is the hot water getting discoloured (rusty or black bits) by the CH water?

 

[doitall]

Has someone stuck a pump on the system. try turning it to it's lowest setting.

 

[ollski]

Has someone stuck a pump on the system. try turning it to it's lowest setting.

Or turned it round, primatics can only be pumped on the return.