Ace high How to repressurise expansion tank?

[richardmlees]

I have a Halstead Ace High Boiler, and think the expansion tank needs repressurising as there is a small but consistent leak from the air vent while the heating is in operation.

While in theory, I know how to repressurise it, and the relevant pressures, I canot see how to gain access without removing the boiler from the wall. Is it possible without removing the boiler?

Thanks.

 

[Whitespirit66]

Don't know anything about this particular boiler, but can you find a Shrader (car tyre) valve on the E V?

This image is a Vaillant, you can see the valve down the back of boiler, looking from above.

Untitled

• Whitespirit66
• 17 Apr 2012
• 3

 

[MANDATE]

My daughter has a halstead ace high boiler and the Schrader valve is on top of the vessel.
You have to make sure you have pushed any water out of the vessel to give maximum amount of 'air' for compression. If the volume of air is too small it increases the pressure and opens the pressure relief valve at 3 bar.
There is always a possibility that the connecting tube can get a blockage which stops the vessel operating as it should.
I'm not clear what air vent you mean. If you mean the AAV (automatic air valve) is leaking, then after expelling any air (which is supposed to do) it should seal and prevent water leaking out. If water leaks out it will allow the water pressure to drop. The 'air' charge in the expansion vessel is not related to the expelling of air from the AAV.
The air pressure in the empty expansion vessel when CH is cold is approx 1.2 bar. The system water pressure is then applied to the same pressure.
Now when CH is swithed on, the heated water expands into the vessel and compresses the air to a higher pressure. you can observe the water pressure gauge gradually increase by about 1 bar.
When heating cuts out the pressure will drop back again.
It is when the pressure starts getting near the 3 bar mark is a indication the expansion vessel has most likely lost some of its'air' charge allowing water to take up space that is allocated for air