Help - Drained CH now doesnt seem to fill, NO hot water or Heating.

Hi all, I need some serious advice / help / an honest reliable heating engineer to do a house call,

I have a boiler mate 2 with a potterton suprima 60 boiler, installed in house in 1998, when it was built, location is Milton Keynes.

Until tonight I had not had any problems with the system, ( always had hot water from taps, rads all got hot quickly) a few years ago I had the blender valve replaced and the PCB also on the cylinder, due to the buzzing noise.

What happened today was that, a friend had been helping retile and refit my ensuite bathroom. I decided to replace my existing rad with a towel rad.

So, I turned off the cold inlet to the small tank at the top, and drained water from a couple of drainage taps on the ground floor rads, one in kitchen one in cloakroom. The water came out clear, and then a very deep brown rusty colour.
I took the small plastic cover off the top of tank, and looked inside with a torch, and could see that it was very rusty brown in colour.
I decided to open the water inlet, and let system fill up a little, the tank was filling very slowly, so I pushed the ball down, and first problem is that the ball fell off its end, so I then manually let it fill towards the top, and then turned the isolator valve back off. I then drained some more water from downstairs.

I replaced the original radiator, did i mention the water in that was black. I opened the inlet valve, checked the level was towards top, and the system appears to be filling slowly?

After a while, I turned the electricity switch to boiler back on, I ensured the thermostat was off, as I didnt want the central heating pump to kick in yet. I then heard some wooshing, and then an awful banging and knocking come from near my boiler. I quickly turned off the switch, and the banging / knocking stopped after a few seconds.

I would appreciate any advice or help.

I hadn't realised that draining the CH system would cause me other problems?

Avey
Milton Keynes

ps. After reading some more advice on these systems, I think I may have narrowed it down to a blocked internal feed. I also want to mention that when I opened the drain valve from one of the 22mm pipes above the boiler, nothing came out (No wonder there was a lot of banging from boiler earlier, I switched it off pretty quickly, hope no damage done to boiler) , as did nothing when I opened the drain valve at bottom of cylinder. Others have suggested filling with hose via the open vent in the F&E tank, or to temporarily connect mains water via isolator valve and tubing to the feed connection at top, or even fill via the drain tap? Somebode mentioned, they got lucky by pushing earthing sleeve down the inlet pipe on top of cylinder?
Any one tried any of these methods, or can recommend which is the "safest" and less likely to cause more issues.

Hi,

Just hoping that my experience helps someone else.

I had to call BG out this morning, and they turned up within a few hours. On the phone they gave me the choice of pay by the hour, or fixed fee £99 + take a new contract for the year, including a service check of my boiler. I opted for the fixed fee and pay monthly.

Whilst waiting for them, I had successfully started to fill the cylinder using my garden hose, via the drain tap.

Long story short..... The BG engineer was very helpful, and he quickly diagnosed it was an air lock, although I had expected something more solid.... he put his rubber tubing into the fill pipe via the F&E tank, and hey presto, water started flowing into the cylinder.
He then also had to change some rubber washers on the mixing valve, as that was dripping a little. Did i mention he also swapped out my broken , cruddy limescale ridden ball cock & valve.
He even tried to fix my weeping chrome pipe tails from the towel rad, and he advised me against using the chrome pipes with copper push fittings. I told him to just cap off the two rad pipes, as I will get that done properly from a plumber, not my DIY attempt.

Regards,

Avey
MK