Proper functionality of a pressure relief valve

[jrtrrror]

Also, it has been suggested that the expansion vessel may need charging or replacing. Could that be a cause of high pressure? What are the symptoms of a discharged expansion vessel?
Ta again everyones

 

[Riley]

There should be a steady pressure rise and then fall once heating demand is satisfied. And please know that we aren’t all rip off merchants. I think shyguy is picking up on the fact that the pressure is not being regulated and is able to rise to 3 and above which is a big no no

 

[jrtrrror]

Thanks Riley.

Two questions if I may.

Could a faulty or discharged expansion vessel be a cause.

What constitutes a steady rise in pressure. 10-15 minutes to reach 2.5 bar?

What actually regulates the pressure? As in, what keeps the pressure at the normal operating pressures. That's a third question

 

[Knappers]

The pressure relief can discharge at any rate but should only do so at 3bar and over.
Issues with the expansion vessel often lead to irreparable issues with the relief valve.
As always faults are best dealt with professionally and quickly to avoid danger and further damage

 

[Riley]

It could be one of a number of causes yes.

Your second question is how long is a piece of string as everybody has central heating on at different times And there are many factors affecting it such as water temperature, hot water usage to name just a couple. Just know that if your pressure is going above three then you have a problem

Correct system design, incorporating correctly sized expansion vessel

 

[Knappers]

Expansion vessels are for expansion, kinda what it says on the tin.
You definatley need a professional!

 

[fixitflav]

Thanks for your reply DuncanM.
Does it release the water in a large 'dump' of water and then close. Or does it release the water slowly. Obviously, if operating correctly.
Thanks again

It opens at its set pressure, but does not reseat until pressure has fallen a little below. Partly because after llfting there is more area of the mechanism exposed to fluid pressure. Water is released till that lower pressure is reached.

 

[Chuck]

Not my favourite part of a boiler .

I have to ask, what is your favourite part of a boiler?

 

[Knappers]

Mine is the empty box it came in!

 

[townfanjon]

I have to ask, what is your favourite part of a boiler?

Lol , a Viessmann heat exchanger