Oops - Help - Oh dear!

[Bloggsyboy]

I have drained the central heating today to fit Thermostatic valves.
I have just looked under the boiler and water is seeping out from one of the pipe joints.
It looks like it's been doing it for years as there is a green all the way down the pipe.
So I looked at the gauge on the boiler which has two needles, a black one on 1.5 bar and a red one off the top of the scale past the red portion.
The boiler is a Potterton 80 combi, the guy who fitted it told me to keep the black needle between 1 and 2 bar but I can't remember ever looking at the red one - is this saying something is wrong???

 

[shambolic]

The red one will be 3 bar and thats the pressure that the pressure relief valve opens at. If you filled it to say 2.5 bar then when the water expands it could go over this and you would lose water. when the boiler then cools down you will drop to under 1 bar!
In short Dont worry about the red line

 

[Bloggsyboy]

Oh thank God for that, I'm trying to save money by doing this myself, thanks Shambolic!

 

[shambolic]

the red one is an adjustable indicator I normally putbit just below one and advise customers if black falls in line with red then top up pressure

 

[Bloggsyboy]

Thanks once again.