Boiler Pressure Gauge - Ideal Classic Boiler on unvented sys

[taycast]

Could somone tell me what the gauge below should read? A friend told me it should be about 1 when system cold, and about 3 when system running. Whats the orange needle for? Thanks

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• taycast
• 20 Sep 2009
• 1

 

[petit_pablo]

Orange needle is a guide as to where to get the black needle to when topping up pressure. If expansion vessel is correct then pressure should remain stable at around 1-1.5bar.

 

[Boilerman2]

The Black needle is the ACTUAL PRESSURE within the System, which if the Expansion Vessel is properly sized should give a Cold Pressure of 1-00 Bar (so you will need to top up your system using the filling loop) this should rise to about 1.75 -2.00 Bar when hot.
The Red needle is an indicator which can be set to show the minimum pressure, (just below 1-00Bar) OR the Maximum working pressure (3-00 Bar)
Hope this helps

 

[bengasman]

It is actually a good idea to make sure the pressure never gets near 3 bar. At about 3 bar, the safety valve will open, and invariably a small but steady leak will remain, which at best means draining the system and replacing the valve. If you want to be safe, keep 2.2 as absolute limit.

 

[taycast]

I added some water when system was cold to take the black needle to around 1 bar, and all worked well. Then today I notice black needle is back down at 0, so added more water to take needle back to 1, and when system fired up, black needle goes up to 3 and water is dripping out overflow outside as previous post described. Any ideas why I seemed to have to top up, then now appear to have over pressurised the system?

Do I need engineer in to replace the valve now?
Does it sound like there was an existing problem meaning I had to keep topping up?
System appears to be working ok other than the outside drip. Is the picture below the pressure release valve? This thing is on top of my hot water tank, not the boiler.

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• taycast
• 22 Sep 2009
• 1

 

[kevplumb]

thats an expansion vessel

 

[petit_pablo]

There should be a red expansion vessel on top of your boiler, behind where the pressure guage is. This needs repressurising. A guide on how to do this is in the FAQs.

The white tank ontop of your HW tank is for the hw tank expansion