Problem with header tank, possible fault with primary coil in cylinder?

jack of all

I've identified a problem with the plumbing/ heating system at home; I'm hoping someone here may be able to confirm my own suspicions regarding the cause and remedy. I've a bog standard installation, approx. 14 years old- oil fired central heating, pumped primary circuit, with an indirect open vented cylinder and domestic cold water tank and header (feed/ expansion) tanks in the attic. The overflow from the domestic storage tank drains into the header tank and the overflow/ warning pipe from this tank terminates externally,at the eaves. So far so simple! I noticed a small weep externally from the overflow/ warning pipe last week. I checked the ballcocks in both tanks and could find no problems but stripped them down and renewed the washers to be sure. The header tank is still overfilling, but takes perhaps a day to reach overflow level; the ballcock in the adjacent cold tank is dripping continuously. This all brings me to the general conclusion that there is leak somewhere in the primary coil within the cylinder, with water in the cylinder under pressure from the higher water level in the main cold storage tank entering the coil and driving up the water level in the header tank. We are in a hard water area although I did fit a water softener some years ago. There are no other problems with elsewhere in the installation and the system has been well maintained from the beginning. Looks like I need to purchase a new cylinder, I'm guessing this will cost somewhere around €300 to €400 plus new immersion heater, fittings and sundries. I plan to do the work myself.

Outkast_IRE

Well you could confirm by shutting off the valve on the cold feed to the cylinder for a day and monitoring the water level the same as you did previously, if the water level doesnt rise with the valve fully shut off then yes its prob a leak in the coil i would imagine.

jack of all

Outkast_IRE wrote: »

Well you could confirm by shutting off the valve on the cold feed to the cylinder for a day and monitoring the water level the same as you did previously, if the water level doesnt rise with the valve fully shut off then yes its prob a leak in the coil i would imagine.

Good suggestion, thanks, I'll try that, although the (useless!) gate valve on the cylinder feed does let water by when fully closed.

Dtp79

jack of all wrote: »

I've identified a problem with the plumbing/ heating system at home; I'm hoping someone here may be able to confirm my own suspicions regarding the cause and remedy. I've a bog standard installation, approx. 14 years old- oil fired central heating, pumped primary circuit, with an indirect open vented cylinder and domestic cold water tank and header (feed/ expansion) tanks in the attic. The overflow from the domestic storage tank drains into the header tank and the overflow/ warning pipe from this tank terminates externally,at the eaves. So far so simple! I noticed a small weep externally from the overflow/ warning pipe last week. I checked the ballcocks in both tanks and could find no problems but stripped them down and renewed the washers to be sure. The header tank is still overfilling, but takes perhaps a day to reach overflow level; the ballcock in the adjacent cold tank is dripping continuously. This all brings me to the general conclusion that there is leak somewhere in the primary coil within the cylinder, with water in the cylinder under pressure from the higher water level in the main cold storage tank entering the coil and driving up the water level in the header tank. We are in a hard water area although I did fit a water softener some years ago. There are no other problems with elsewhere in the installation and the system has been well maintained from the beginning. Looks like I need to purchase a new cylinder, I'm guessing this will cost somewhere around €300 to €400 plus new immersion heater, fittings and sundries. I plan to do the work myself.

What size is your cyclinder ?

jack of all

Not sure, somewhere around 150- 200 litres.

jack of all

I bit the bullet, ordered a new cylinder last week and fitted it today- problem solved! What a joy to have (clean) hot water on tap again!