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Piglet John where for art thou? Please help?

(22 Posts)
PartyFops Fri 12-Dec-14 17:33:58

My dad has messed up my central heating.

I moaned to him that my rads weren't getting hot enough to he offered to come and flush them for me.

So he did! He put the stuff to flush it in the system and left it for 6 days. During this time one if the downstairs rads stopped working (the pipe to the rad was hot but not the rad itself).

Today he came and drained the system again and now 2 rads in the living room don't work!

We have a gravity fed system with drop rads (if this makes sense?). He tried to drain the downstairs drop ones but nothing came out of the drain valves underneath. We then decided to drain from the top bleed valve, which did make the rads warm up whilst they were being drained, but then got cold again after. We are at a loss of what to do next.

Can you advise anything to try. I'm cold! 😁😁😁😁😃😃

PartyFops Fri 12-Dec-14 17:34:49

Please smilesmilesmile


specialsubject Fri 12-Dec-14 19:56:15

airlock somewhere? Are all the radiators that work warm right through? Have you bled everything?

PartyFops Fri 12-Dec-14 20:06:46

We suspect an airlock somewhere.

All up stairs rads are red hot. We have got all rads downstairs hot bar 2. One of those is luke warm all over, the other is stone cold, even the boxed pipes that run up to the ceiling are stone cold.

All rads have been bled confused.

How can we remove an air lock?

PartyFops Fri 12-Dec-14 20:34:23

Can I add that when you open the drain valve on the pipes underneath the downstairs radiators nothing comes out (or sometimes maybe a trickle) so we are struggling to drain and re fill.

roneik Sun 14-Dec-14 11:48:56

Somewhere at the furthest radiator you may have an inline drain valve. You need a little key four sided to turn the draining valve, Sometimes you can get some long nosed pliers to turn the valve if it is not too tight. You then run a hose to an outside drain or whatever. You need to turn off the mains before starting as the header will keep replenishing the system defeating the aim of the task.

roneik Sun 14-Dec-14 11:53:57

This valve is one type, older systems have it soldered into the 16mm pipe

roneik Sun 14-Dec-14 11:55:11

15mm pipe senior moment with the keyboard, and I have corrected before the piglet comes on to correct my error grin

southeastastra Sun 14-Dec-14 11:56:03

do you need to balance them?

roneik Sun 14-Dec-14 12:02:04

I am just a diyr, when I have drained my system, I just turned the water off, then my inline drain valve opened to release the water from the system.
Then I filled up with an added additive at header, turned water back on.
I did leave the valve a tiny bit open to expel any air after testing.
Voila no more knocking pipes and cold half heated house.
I hope this helps

roneik Sun 14-Dec-14 12:06:57

Of course after a few minutes I did tighten the inline drain valve up.

If I hadn't my furniture would eventually floated down the street, with the dog sat as captain on the sofa with kerchief and a spyglass to bootgrin

PigletInABlanketJohn Sun 14-Dec-14 12:12:17

Turn off all the hot ones. Do the cold ones now heat up?

roneik Sun 14-Dec-14 13:38:53

She will end up in a blanket too if they don'tgrin
Snoopy had a comfort blanket too

PartyFops Sun 14-Dec-14 19:17:32


They are all hot bar one now. Tomorrow when my dad comes back to fix this he is going to turn them all off and see if the cold one works. We think there is a big air lock as he acknowledges that he didn't drain them correctly.

There are those drain valves on all down stairs rads as they are drop rads. We also think the valves have seized as they don't drain at all.

PigletInABlanketJohn Sun 14-Dec-14 19:22:26

it might not be an air lock.

Post pics of the rad valves and the drain cocks if you can.

What was the chemical cleaner used, and what colour was the water that drained out?

PartyFops Sun 14-Dec-14 19:34:55

Is this ok?

PartyFops Sun 14-Dec-14 19:35:44

The pipes to this rad are cold all the way up to the ceiling.

PartyFops Sun 14-Dec-14 19:36:56

I'm not sure of the cleaner used, the water that came out was quite black, but not thick sludgey.

PigletInABlanketJohn Sun 14-Dec-14 20:03:48

the drain cocks you show have a rubber washer in them. After years of heat, this perishes and sticks. If you screw the brass plug right out, then water will probably gush out of the hole (if not, poke a bit of wire up). You could try loosening it then poking a wire up the spigot. Drop loops are quite tiresome.

It will not do your flooring any good.

Unfortunately there are several brands of cock with different washers, best plan is to wait until draining has stopped, then take the plug to a plumbers merchant. If you are really lucky, there may be a makers name on the cock. If you can buy new ones the same, unscrew the plug and screw them into the existing shell. It will be much easier than replacing the whole thing. If not get some new washers if you can. If you have a drain cock in a more convenient position, drain that one first and take the plug out so you can be prepared for the more difficult ones.

It will help to put a hose on the spigot first, and to press your thumb on the open end until all the water has come out.

I think the problem is much more likely to be that the radiators need balancing, rather than an air lock. Turning off all the hot ones will verify that.

When the black sediment has been loosened by the chemical, you need to drain and refill several times with clean water until it no longer seems very black.

The radiator valve in your picture is a TRV. I don't recognise the brand.

PigletInABlanketJohn Sun 14-Dec-14 20:04:57


the TRV in your photo is set to "0" which is, loosely speaking, "off" so the radiator will not heat up unless the room is very cold.

PartyFops Sun 14-Dec-14 20:17:32

Thank you so much for your comments Piglet John, I will talk with my dad about it tomorrow.

Btw, I do know that the thermostat is on zero gringringrin

PartyFops Mon 15-Dec-14 14:16:20

All sorted, thank you. We turned them all off except the cold one and there was a big gurgle, all now balanced and working.

Will get an engineer to replace the drain cocks at some point. I suspect they can do it when they do a power flush.


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