Header Tank

7 Replies

We need a Header Tank...... have never spotted one here in Brittany, has anyone else spotted them?misspMissP(aka: Misspx before I forgot my password)

Featured Classified


gerbil-384064 1089979339

What sort of header tank do you want. House water supplies in France are often pressurised from the mains supply (unlike the UK) so do not need header tanks. The same goes for central heating systems.


dave-382311 1089983334


Never ever spotted a header tank anywhere in france yet !

@+ dave

bob-381779 1089989652

Header tanks do not comply with the "norms" in France which are designed to avoid Legionnaires disease. Hence the pressurised hot water tanks system.

Even the expansion tanks for hot water central heating were stopped being used, you now have a pressure/expansion vessel and sometimes a dry overflow tank which runs out immediately.

If your water pressure seems low, you probably need to turn it up at the pressure reducer if fitted, sometimes found just after the stop tap into the house but ideally just before the hot water tank.

If in doubt, consult a plumber here





MissP-384627 1090063162

Thanks all. I am no expert on this but the scenario is as follows: We have excellent water pressure, however we have a woodburning stove with back boiler from which we will be running 5 radiateurs and hot water during the winter, therefore we need a small header tank upstairs. Looks like I will have to resort to the Screwfix catalogue.

(aka: Misspx before I forgot my password)

Perret Barry 1090090571

Plumbing 101 - Central Heating Systems for beginners..

It is normal to have a closed expansion tank - Vase d' expansion mounted on a four way (cross) fitting.  It is an accumulator, with a diaphragm and either spring or gas pressure.  It allows the system to achieve operating pressure, and then accomodate the increase in volume as the water expands.

On the hot (upward rise) from the Boiler - Chaudiere, an Air Release Valve - Purgeur, is located at the highest point.  The Hot pipe is then connected to the 4 way (cross) fitting.  Directly accross - the pipe goes to the Central Heating Pump - Accelerateur, and on toward the radiators.

The remaining connection to the 4 way fitting usually goes to a christmas tree of valves...Pressure Relief Valve - Clapet Detendeur, which is connected to a drain pipe - out of the building. 

It is also normal to charge the system at this point via a Non-return Valve - Clapet de non-retour.  The system is isolated from mains water after filling by means of a stop valve - Robinet d'arret.

So there is not a need for open header tanks...

Incidently, most new Hot Water installations in the UK are being installed the French way - using mains water pressure, and NO header tank.

Best of luck!

Barry N

sydhancock 1090094010

Thanks for the clear and detailed explanation.

Like the person who first raised the question, we have a back boiler which transfers heat via convection (I used a UK indirect cylinder). This is for domestic hot water only, not central heating.

In other words, the hot water comes out of the top of the back boiler, goes up by convection into a coil in the hot tank (heats up the water in the tank) and then returns back down to the bottom of the boiler. All fed by gravity - no pump.

There is a large cold tank feeding the hot water cylinder and there are hot water expansion pipes from the top of both the cylinder and from the heating loop which allow the hot water to expand when it gets very hot - it often boils in fact. The heating loop is also topped-up with cold water from a tank.

I know this is a UK way of doing things but it was all that I knew when I installed it some years ago.

Can this be arranged without header and feeder tanks? Should I be using a sealed convection loop with an expansion chamber? There is a lot of pressure when the water gets very hot.

Also, what sort of vessel can I use for indirect water heating that will take also mains pressure?

The boiler is of a type originally used in France (make is called Franco-Belge) but is this sort of installation now possible in France?

Any advice welcomed - this has puzzled me for a while.


Norwich UK & 22530 St Connec

BlueRoans-386259 1110015806

Miss P, we have a new/unused Header Tank if you want it.  I have emailed you.


Join the discussion