What is my system: closed or open ?

[bcollet]

Hi There,

My radiators are not very efficient and I suspect that the GCH system is full of sludge and/or air and need to be flushed and/or treated.

The boiler is Ideal Mexico type and I have 2 cold-water tanks in the attic one for the hot water tank and another one for ... I thought the radiator circuit ... until I attempted to drain it:

I switched off the GCH and the turned off the main water supply, open the drain outlet (I have two in my system on at the lowest point in the house from a pipe, the other one out of the lowest radiator). I managed to get only about 5 liter of absolutely clear water and then it stopped.

When I turned on the water again, the circuit seemed to fill up again but nothing happen at the attic cold water tank.

When I try to drain without switching off the main water supply I get some pressure so the system seems to be a closed circuit ...

So my question is why do I have a second cold water tank in the attic which seems to do nothing ?

Second question: when I bleed radiators, I got air or hydrogen coming out and then some black water (definitely some sludge here !), so why when I drain the system from the drain outlet I get clear water ?

In the case my system is a closed circuit is that procedure for cleaning it ok:

1. Switch off GCH
2. Turn off the main water supply
3. Drain at the drain point.
4. Inject some X400 or CH restorer solution with a large syringe into a radiator by a bleeding point.
5. close everything switch on the water supply again and the GCH
6. Let on for 1 week ?
7. Drain several times
8. Repeat using a corrosion inhibitor.

Sorry if this question seems very naive but that's the first time I have to deal with GCH.

Thanks a lot in advance

Bertrand

 

[ChrisR]

SHort answer: you have an OPEN system but the feed pipe is blocked with scale. That needs fixing before you deal with the rest. Pipe may need to be cut out, though sometimes it's possible to use the mains to force it out. Then you'll need a powerflush, with more powerful chemicals than X400.
If you do a search you'll find those keywords quite a lot!

 

[bcollet]

Thanks for the quick reply. But if the feed pipe were blocked I would have an empty system at present (or at least partially) ?

I did drain it while the main water supply was off, but it refilled as soon as I turned on the water supply again.

And the cold water tank in the attic did not react at all (although I previously check that it was filling ok when the floater was pushed down).

Bertrand

You have just answered your own question

correct me if i am wrong but you drained app 5 l

sorry for the grammer and punctuation chris
but i'm only a raggy arsed installer

 

[ChrisR]

You're losing me:

but nothing happen at the attic cold water tank

the cold water tank in the attic did not react at all

only got 5 liters out

SOmething is wrong.

 

[bcollet]

Sorry for the confusion:

I tried two things (the GCH was off at all time):

1)
- turned off main water supply
- drained: very low pressure, got only about 5 l then stops, clear water.

2)
- turned on main water supply (I heard the system filling up but not via the attic cold water tank).
- drained: high pressure, still clear water. No reaction in the attic water tank (in an open system this should top up the circuit, no ?).

Bertrand