Potterton Ideal Classic - noise

Robert Tyrrell · Jan 20, 2015

I got called to a leaking drain off on an Ideal Classic the other day and had to drain the system to repair it. I refiled the system and bled all the rads before leaving but now it appear that the boiler is making 'Gurgling' noises and two of the rads aren't heating; one at he very top of the system (Negative head) and one on the ground floor.
The thing is that I only drained the system to the level of the boiler, which is above the ground floor rads, and it’s a sealed system so I can't quite work out why this has happened and would appreciate some advice. The topmost rad is on the same level as two others that are working fine.
I can't access the boiler without taking off the cover and I'm going to presume that it’s a positive pressure case so as I'm not Gas Safe [yet] I shouldn't really touch it. I can't see any AAV on the boiler (There might be one inside the casing I suppose), and I can't see a way of adding anti kettling fluid directly into the boiler.
Can any of you fine fellows explain:
a: Why the boiler might be making the 'Gurgling' noise and how to cure it? (I do know about kettling - I was wondering if it might be something else)
b: Why the rads might be cold and how to cure that? I could understand it id f there was an airlock but all rads have water to them.
I'd just like to have some idea before I head over to the job so that I can get my head in the right place for working it all out 🙂

Millsy 82 · Jan 20, 2015

Sounds to me like you still have some slugs of air going round it. Just keep bleeding it and it should sort it self out. With the radiators not working try turning the others that are working of and force the water through, with it being a pressurised system how high the rad is won't make much difference.

There is no auto air vent in the classic so no need to touch the boiler.

Robert Tyrrell · Jan 20, 2015

Millsy 82 said:
Sounds to me like you still have some slugs of air going round it. Just keep bleeding it and it should sort it self out. With the radiators not working try turning the others that are working of and force the water through, with it being a pressurised system how high the rad is won't make much difference.

There is no auto air vent in the classic so no need to touch the boiler.

Cheers, didn't think that there was a vent in the classic - I've worked on one or two (under supervision of course) but I was just checking.
As far as the bit of air still moving around; that was another of my thoughts and I did tell the customer to bleed all the rads again - told him he might have to do it a few times, and get a few litres of water out of the system before it settles down.
I also know that a sealed system can easily cope with a negative head - just thought that I'd throw it in there, so to speak 🙂