Air in a pressurised system and water in tundish

[AndyT68]

Evening all,

After having the heating on for a couple of months now, I've noticed a drop in system pressure - 1 bar down to 0.25 bar. Along with this, I've noticed the rads on the middle floor (of 3) are not heating up.
This evening, I went round and bled the 4 rads and a lot of air came out, so much so, I had to charge the system a couple of times back up to 1 bar.
Anyway, when I had finished the bleeds and got the system at 1 bar, I noticed cold water was dripping very quickly in the tundish. Seemed to drip like mad for 5 seconds, stop for another 5 seconds and then start dripping again.
Is the air in the system and the dripping into the tundish related?
Ideal classic boiler and Megaflo cylinder.

Thanks in advance.

 

[Blagard]

Sounds like the relief valve on the central heating side is faulty and maybe even allowing air to be sucked in when your system is running.

 

[AndyT68]

Would that be the big valve before the cold water inlet to the cylinder?

 

[Blagard]

Can you post a photo?

The thing is the ideal classic comes with either a sealed system module or it can be done by the plumber/heating engineer as a collection of parts.

The tundish on the megaflow sealed hot water system should be unrelated to the discharge from a relief valve on the boiler but it sounded like the plumber had connected the boiler relief into a tundish. If your tundish only drips when the central heating side is charged up they are related.