Right pressure in Baxi 105e

[Querolson]

Hi there,

I have just bought a new house that has a Baxi 105e combi boiler and was serviced every year by British gas. We got the property in September but didn't move till mid November, and didn't use the boiler "full blow" till then. I only switched it on and allowed it to run a couple of hours the central heating when it started to get cold and freeze during the night around the end of October in order not to have the pipes frozen. The boiler seems to work beautifully, but the problem is that the pressure was low and I raised it via the loop circuit to 0.5 bar. Fine there, but when I have the central heating on, it raises between 2.4 and 3.2 bar, depending if it is firing or not. Obviously, if I bleed the radiators meanwhile working, and set a comfortable pressure of 2.3, the pressure drops to 0 when cold. It doesn't prevent it to work correctly when the timer switches it on or the hot water is needed, and doesn't misfire, but I'm worried about the future and if letting it go to so high pressure will damage any part, and equally, letting it go so low pressure when cold will do de same. Any suggestions?. Shall I let it be with a 0.5 bar when cold and with 3.2 when the CH fires or shall I let it work with below 2.5 and allow it to go to 0 when cold?

Sorry for such a long one, and Cheers.

 

[bengasman]

see faq

 

[Querolson]

Which one?. Where are they?. Sorry, new to the site...

 

[bengasman]

5th line from the top of the forum on the page where you posted this question.
beneath the bit that says: read this first

 

[Querolson]

Thanks, so you think that is the pressure vessel?.

 

[Querolson]

Now, today I have realized that the pressure goes right to 0 when using the hot water, or the boiler is preheating. When finished, goes back to the pressure that the CH has.Is this normal?

 

[bengasman]

exp vessel flat or dead

 

[Querolson]

Thank you very much. The bicycle pump with gauge cost me £19, but worth every single penny, since it had a flexible extension and if not it would have been virtually impossible to attach it to the pressure vessel's valve. I opened a draining cock next to one of the radiators, and to my surprise no water came out, so I left it open with a jar under it just in case and pumped the pressure vessel which, surprise, surprise, was completely flat. Put about 1 Bar and the pressure went up to 2.5 from 0. Closed the cock next to the radiator and drained that radiator till the pressure was 0.6 Bar.

Now the CH works as before, but the maximum pressure I've seen is 1.7 Bar which is whitin range. Still drops about 0.5 Bar of pressure when I open the hot water tap, but I guess that it is normal, isn't it?

Thank you very much Bengasman.

 

[ChrisR]

The running of the pump alters the pressure the gauge sees.