What water pressure.

[AnOther]

I wonder what the recommended nominal water pressure is and what various people actually run at.

My boiler's manual says it should be 1.5 bar cold but it is running @ 3.5. There is no separate reducer for it and if I turn the main reducer down to 1.5 the pressure in the rest of the house is useless.

One thing I've learnt recently is that SAUR seem to have some sort of safety pressure trip in the line. I discovered this when replacing my entire pipe recently and as precursor to connecting it in the house gave it a quick burst whilst still open ended to blast out any debris which may have got in it. The result was an immediate reduction in mains pressure from a nominal 8 bar down to 1 and I had to call SAUR to get them to reset it. It was done in under an hour.

[Théière]

ErnieY, I don't know your boiler but don't you set the pressure with a filling loop like a regular combi style?

[AnOther]

My oil boiler is circa 1970 something fed direct from the mains with an expansion tank, I know nothing of combi boilers or filling loops [blink][blink]

[Théière]

[quote user="ErnieY"]My oil boiler is circa 1970 something fed direct from the mains with an expansion tank, I know nothing of combi boilers or filling loops [blink][blink]

[/quote]

Oh well if it aint broke don't try and fix it!

[AnOther]

Agreed but in the name of the quest for knowledge........................[:)]

[Théière]

As long as you don't follow up with:

Any one know where I can get a new Boiler

Better to play with it during the summer when you don't need it, now pour another glass and sit down and think about something else. [:D]

[jondeau]

I would imagine that opening an open ended pipe has created a bit of a surge in the supply line, this may well cause the pressure governor controlling your area to 'lock out' in which case it would need to be manually reset.

When 'lock out' occurs the governor will normally have a by pass rate which it will default to, to maintain a minimum pressure in the region.

It would seem  a bit far fetched in the UK for one open ended pipe to cause lockout........but maybe in rural France supply loops are limited and maybe this caused the problem

 

[Dave&Olive]

[quote user="ErnieY"]I wonder what the recommended nominal water pressure is and what various people actually run at.

My boiler's manual says it should be 1.5 bar cold but it is running @ 3.5. There is no separate reducer for it and if I turn the main reducer down to 1.5 the pressure in the rest of the house is useless.

One thing I've learnt recently is that SAUR seem to have some sort of safety pressure trip in the line. I discovered this when replacing my entire pipe recently and as precursor to connecting it in the house gave it a quick burst whilst still open ended to blast out any debris which may have got in it. The result was an immediate reduction in mains pressure from a nominal 8 bar down to 1 and I had to call SAUR to get them to reset it. It was done in under an hour.

[/quote]

hi ok

         you have answered you question yourself...

 My boiler's manual says it should be 1.5 bar cold but it is running @ 3.5. There is no separate reducer for it and if I turn the main reducer down to 1.5 the pressure in the rest of the house is useless.

The result was an immediate reduction in mains pressure from a nominal 8 bar down to 1 and I had to call SAUR to get them to reset it. It was done in under an hour.

if your boiler is running at 3.5 bar and the mains is 8 you must have a  second pressure reducing valve some where

        Dave            

[jondeau]

It is normal in the uk.........nay obligitary and essential, to fit a pressure reducing valve on the mains water supply to a combi boiler...........

Pressure reducing valves are widely available in France........unfortunately french plumbers are somewhat behind the times.

[Le Plombier]

If your boiler manual says the pressure should be 1.5 bar have you ever considered that your boiler is designed for a sealed and not an open vented system

Le Plombier

[AnOther]

Jondeau: Sounds plausible. Means that I probably took my neighbours down at the same time [:$]

Dave: I assure there is no second pressure reducing valve. The pressure out of the meter is 8 bar (I have an accurate meter which I checked this with) then, where the pipe enters the house, there is a reducer which is set to 3.5bar - that's it. The gauge on the boiler reflects this.

Le Plombier: I do not know the difference, I think my system is sealed, are not all French system sealed ? It was professionally installed not a DIY bodge job in 15 & 22mm UK copper [;-)]

I have however been re-reading the manual and it seems that the reference to 1.5 bar is for a system without an expansion tank which mine has so a bit of a red herring I'm afraid. Max pressure in the boiler spec is 6 bar.

A correction to my earlier post too, the boiler is circa 95, the house was built in the 70's, apologies.

Nobody want to say what pressure they run at ?

[BIG MAC]

UK Requires combis not to be directly connected to mains hence the nice wire braided filling loops dangling beneath the domestic boilers of the land.

Pressure regulator on incoming charge will be the tap that is operated to inject the new charge of water and the failsafe for the hard of thinking will likely take the form of a blow by valve spewing outside...........Commercial systems with make up units are a different proposition.

Ernie norm is usually about 1.5bar standing and 3 or 4 bar normal running but this varies if you can find the relief valve it will likely be calibrated to let by at 5 or 5.5 to protect the system. If you can't get pressure stabilised it may be that the expansion vessel may need recharging or the gas bag has possibly given up. 

To be honest these things are best left to professionals particularly as pressurised systems can cause quite a bit of damage if they go awry.

[AnOther]

Thanks for all the replies.

I never said I had pressure stability problems BTW, I was just interested in what pressure was the norm and so far my 3.5 seems to be nominal.

[Le Plombier]

I am really confused by this one as I cannot clearly ascertain what your problem is

Normal pressures are -

Incoming mains water 6bar up to possibly 8bar, varies as to whether your are in a town or rural area

Recommended and in the majority of installations fitted is a pressure reducing valve to reduce and maintain mains pressure in the house at 3bar

Boiler maximum pressure, with a sealed system, is 3bar at which pressure the safety valve will discharge to protect the boiler

Boiler normal operating pressure between 1 to 2bar

If the heating system is an open system the open vent off the expansion tank will start to discharge long before you reach this pressure

Hot water, both off a heating boiler and chauffe eau, should be protected by a groupe de security which will discharge at 7bar to protect the hot water tank

You need to define more clearly what your pressure problem is so someone can give you a proper answer

Le Plombier

[AnOther]

Perhaps not surprising Le Plombiere as I don't have one !

I initially queried discrepency between what my boiler manual said, which was 1.5 bar, and what it was actually running at, which is 3.5 bar. I subsequently realised that the 1.5 bar number related to a system without expansion vessel which is not my case and said so in a later post.

My system is indeed as per everything you say [:)]