The boiler has been installed for about 4 years as part of a new mid terraced property. The boiler continually loses pressure until it locks out and I don't know why. I am currently having to refill the boiler, increasing the pressure to about 1.5 bar and then resetting it. The system then works for a number of hours but during this time the pressure begins to drop steadily until it locks out again (I am having to do this once or twice a day!) Does this mean I have a leak somewhere or could there be other reasons for this happening and how can I identify the cause? Any advice appreciated.

Jonathan, January 2009

Refer to Billy's answer Feb2012 - worked for me.
I need to do this about once a year.

Prior to that I changed the red pressure relief valve which made no difference and had been topping up with water for a year previous - Gradually getting worse from once a month to every three days then every 3 hours. Problem no longer exists after re-pressuring the expansion vessel - I used a small foot pump and accessed the valve by removing only the front screws on the top front panel then slide hand underneath with pump hose from the bottom of the panel. (6 year old Potterton HE Powermax)

Rick from Ipswich, March 2013

I had this, it turned out to be a problem with the primary expansion vessel. I opened up the boiler, released all the water using the red valve, took the primary expansion vessel out and emptied the water. Do this for both the open hole and from the valve until there is no more water. I then put it back in and re-pressurised it to 1 bar according to the bottom guage. I then upped the pressure to 1.5 bar using the water. The first time I powered it up it errored with code e03. I then let some air out of the bike valve then topped the pressure back up to 1.5 bar with the water. It took a few gos but once I got the ratio right it was ok.

Not a plumber and no expertise., February 2012

You know guys, the expansion vessel is nothing to do with the boiler. It is not made or distributed by Potterton and is selected and installed by the Installer, yet Potterton get the stick for it. The main cause for the pressure loss problems usually are the expansion vessel or in many cases by the PRV letting by after plumbers/installers have been lazy and drained the boiler via turning the red cap to relase the pressure. THIS IS A SAFTEY VALVE not a drain cock. Unfortunatly in doing this they allow contaminated system water to flow through this valve which invariably leads to a small piece of debris getting under the valve seat and allowing water to pass to the outside via the discharge pipe, hence the pressure loss.

The expansion vessels (one of which EVERY pressurised boiler/system has) can and do lose pressure due to a 25p bike tyre valve, they also suffer from the rubber diaphragm splitting internaly.

I have worked on almost every type of boiler on the market here in the UK and some in Australia, they all suffer from this from time to time. At least on the Powermax HE they are accessable as they are external to the boiler, not like some which are fitted internaly at the rear of the bolier which must be removed to allow replacement and as for the HE being experimental......... the same heat exchanger is used in what is called the Market Leader's boilers also. The gas valve is made by Honeywell (fitted to almost every boiler on the market) almost every other component is in constant use every day on thousands of boilers accross the nation.

With 40 years of experiance I could not put my hand on my heart and swear to you that any one boiler is foolproof.

Get a profesional to find the fault, its s lot less painful in the end.

R. Barnard (Ex BG engineer), April 2010

You have a leak in the pressurised part of your system; may require a new heat exchange coil in your hot water tank. Check for leaks in the pipes that go to your radiators, if you don't find any it could mean there is a leak somewhere worse like in the tank itself or under your floors.

Billy, February 2010

the answer to most of the problems listed is that there is water instead of air in the primary expansion vessel.when the water in the boiler heats it expands into the air in vessel, compressing the air, if the vessel is filled with water, as water does not compress,it comes out of pipe sticking out of house via pressure release valve. to remedy this take off top cover and the two topmost front covers(1 of grey). bleed off all the water from system via PRV(turn red knob towards you about an eighth of a turn until you hear water flowing out) do this until pressure drops and low pressure warning comes up on display or until you stop hearing water flowing. next, on the primary expansion vessel, which is located at the top left of the boiler(grey in colour),you may have to take off metal cover to access, there is a valve at the front(same as you get on a car tyre), take off cover and use a bicycle pump to pressurise to 2 bar, your digital display will let you know when you have reached this, take off pump and press pin in valve to bleed off pressure down to about 1.3 bar. thats the job done apart from replacing all the covers that you took off. very easy DIY job that you can do in 20-30 minutes with a phillips screwdriver and bicycle pump. good luck

billy gibson, January 2010

Same problem same boiler

Jim Fuller, December 2009

I am in the same situation with lockouts and reset on a 4 year old Powermax HE boiler. Problem started early last year but I have now sent a mail to the chief executive of Potterton, Mr. Martyn.Coffey at baxigroup.com

Surface mail to:
Martyn Coffey
Chief Executive
Potterton
Brooks House
Coventry Road
Warwick
CV34 4LL

Claim your money back, the product is not fit for purpose.

Vince, June 2009

it will be a leak or the expansion vessel itself or the hose. Is the pressure rising when the central heating is on?? to around 3 bar?

boiler bill, March 2009

You are not alone! I and many others have also had the same problems with a Powermax HE, with increases and reductions in pressure with consequent lockout. The boiler was a builder's installation in 2003 and most residents in the development have called out engineers many times per year. The problems are with leaks, malfunctioning pressure relief valves, expansion tank. I was told these were ' experimental' and few engineers like working on them. I am considering claiming under the NHBC warranty as it seems they are 'not fit for purpose'. Sorry I can't be any help.

sidewinder, March 2009

We had the same problem last year and actually had over a dozen visits by british gas engineers, eventually one of the engineers diagnosed the problem to be a blockage in the flexible pipe between the boiler and the expansion vessel, it is likely that you have the same problem. Be interested to know if it is

John Foster, February 2009

hello . i am having the same problem with my own potterton powermax 115.this is the 3rd time its happened on a 3 yr old boiler.plumber guys come and change a part ,last time it was a by pass pipe and 12 months later here we go again.its c p. this is the worst boiler i have ever had fitted. as a property developer i have fitted loads. next time i will go bosch.
these are c p.if i get any more info for you over next few days i will be in touch.good luck.mick.

potty potterton, January 2009

yeah you've got a leak

me, January 2009