Heating issue / boiler trouble

[ACurlyWurly]

Hi
My radiators upstairs were half full with water so I decided to bleed them. There was no hissing of air and water level didn't change. Radiators downstairs were all full and hot.

I had a look in airing cupboard and I see attached photos. DW turned top valve and quickly turned it back but I was not sure if that should be open or closed.

All pipes at bottom are getting hot

Now all radiators a stone cold. Top red tap has developed a drip! So I have turned it to closed now.

There are two switches on wall one is off and connected to top of tank and appears to do nothing. Other was on and all noise stops if I switch it off

Boiler (downstairs) makes noises and has flame. Red thing (pump?) is boiling hot

System is gravity fed

Any clues? I am waiting until tues to get someone to come out and don't need the heating / hot water as it's warm and I have electric shower so can wait

I've now turned it all off in a panic!

Is there a pressure guage on the boiler? Sounds like not enough water. If it's gravity on the radiators as well as the hot water it could be a blocked feed pipe.

Were the radiators cold at the top or bottom?

Sadly no pressure gauge on the boiler

Cold at the tops hit at the bottom

*hot

What happened when you bled them? Did water come out?

No. Downstairs ones water came out. Upstairs ones had brief his of air (a second or so) and then nothing but there is hardly any water in them. Now been told that 'both radiator valves have been fiddled with. Just read about lockshields?!? Think we may have a new exciting balance issue too! How do I fix that arghhhhhh

Also. Switch in photo (blue) is off and will not physically switch on. The switch is stuck and goes half way but doesn't turn on. It's attached to grey thing on top of boiler. What's that for?

Pic

Research has told me I have vented heating system
Yesterday all was fine downstairs but upstairs had half heated rads. Bleeding upstairs but no water came out and very little hiss of air

Some uneducated fiddling with lock shields to try to get air out of upstairs heating and now all rads are cold in house. Not sure of original positions.
No pipes leading into any of the rads are e warm at all
Boiler is getting hot.
All pipes in airing cupboard are hot
No heat at all

Is @pigletjohn up? What have I done people?!?

You have insufficient water in the system. There is probably a blockage in the feed pipe.

Go into the loft and look for a small water tank about 2ft long x 1ft high x 1ft wide. It will have a ballcock in it like an old WC cistern.

1. how deep is the water

2. how deep is the mud

3. does water run in when you push the float down.

I'm in the loft
Mud is lower than outlet pipe (who would thing there was mud!
Water is full and refills when I push it

The pipe coming off that tank and has a red tap (pictures above) and has developed a drip coming from it at the moment!

@PigletJohn you superstar! I have been fiddling with the tank and stuck my finger in the hole as bubble bubble there is water back in the system and rads are pumping out heat!

Next question do I need to clear out the sludge?

Yes

tie up the float so that the mud is not washed into the pipes

scoop it out into a bucket with a cup or lable, wipe clean with a sponge. When clean and empty, wipe the inside of the tank, and the lid, float and vave, with the sponge and bleach (mould can grow in the tank, this will temporarily remove or prevent it). Don't pour bleach in just wipe it.

Noe look for the drain cock, which will be at the lowest point of the radiator pipes, maybe nextto the boiler, maybe on a radiator. With luck it will be near the back door so you can attach a hose to it.

Don't do any more just yet, if you can find it, I will explain how to do a simple chemical clean which will help get soft sludge anddirt out of the system. The purpose is to reduce the risk of a blockage happening, which will need professional attention. A chemical clean may prevent that, and is fairly cheap and easy.

The drain cock you are looking for will look something like one of these.

www.screwfix.com/c/heating-plumbing/stop-cocks/cat831690?cm_sp=managedredirect--plumbing--draincock

I have found the drain cock and yes it is near the back door, for now i am going to clean out the sludge before deciding if I am confident enough to take the next step....may chicken out and call a plumber :)

Thank you so much @pigletjohn for helping me out on this !!!

OK, but if you start the chemical clean a week or two before the plumber calls, quite a lot more dirt and sediment will be loosened and come out during the drain. It's the dirt and sediment that caused your recent problem, and will likely do it again, so getting rid of it will do nothing but good.

The chemical costs around £20 and can be left circulating for up to four weeks before draining. After that, the dirt starts to settle again.

The plumber can do a machine half-day clean which will cost several £hundred so your DIY clean may save you a lot.