Central Heating Disaster

[blackrat779]

Hi,
My heating system wont empty or fill.

My heating has been acting up and it was suggested it might be a sludge build up.

I bought some de-sludge stuff Sentinal X400 and started to drain the radiators down. Water came out of the hose and the radiators gurgled ect until it stopped.

I opened up the bleed screws on the upstairs radiators and a little more came out of the hose. I went to bleed the downstairs rads and some still have water coming out the bleed screw even though there is no more water coming out of the drain pipe!

I went into the loft and the header tank is still full. I tried plunging the header tank where the water goes through the bottom but nothing it still full.

I've had to stop for the evening with empty radiators and use the immersion heater for hot water.

If I can't get the header tank to empty I'm stuck with some empty rads and some full! Just to confirm the mains water was off while I was doing this.

I would be grateful for any help please

BR

 

[TonyW2]

Do you have a cold water tank that can feed through to the f/e tank, even with the mains off? Did you tie up the valve to stop water refilling it?
Are the downstairs rads fed from pipes in the ceiling?
Can you get someone to watch the f/e tank whilst draining.

 

[blackrat779]

Hi Tony,

No the only water entering the header tank is from a mains supply with a ballcock. Yes the pipes for downstairs rads come down the wall from the ceiling.

 

[Newboy]

It sounds as if you have a blocked feed pipe (common fault).

Two course open to you:

1) May be possible to convert to combined feed/vent but you need to ensure that your setup is suitable for this approach.

2) Cut out the blocked feed pipe and replace.

Both approaches will need some understanding of the system layout and suitable tools & skills

Do a quick search on "blocked feed pipe" in this forum and your questions will be answered!

 

[blackrat779]

Thanks newboy.

Both answers are beyond my ability sounds like I will have to get someone in.

Thanks for the reply

BR

 

[TonyW2]

Sorry late edit.
Well the downstairs rads would need emptying individually and water from the ceilinh pipes would come out of their bleed valves, but if the f/e tank is remaining full, of seems you have a blockage in the exit pipe that supplies the heating circuit.

 

[blackrat779]

Hi Tony,

I have spent most of the afternoon plunging the header tank but no joy the water isn't going anywhere, no bubbles ect.

One odd thing though, there is a curved pipe that comes up behing the ballcock valve and empties into the header tank. After plunging the exit pipe for a little while a small amount of water comes out of the curved pipe, probably nothing.

BR

 

[dcawkwell]

Attach a hosepipe to the drain valve.
Close all the bleed screws and connect the hosepipe to the mains open tap a little and it will start filling up.
Let the mains pressure do the work.
Water will eventually come out of the vent pipe perhaps bleed the radiators and you are up and running.

 

[blackrat779]

Hi dcawkwell,

Thanks for that, sounds like it will be a temporary fix till the weather warms up ant any rate. I will give that a go first thing tomorrow.

Where will I find the vent pipe?

Cheers,
BR

 

[dcawkwell]

Hi dcawkwell,

Thanks for that, sounds like it will be a temporary fix till the weather warms up ant any rate. I will give that a go first thing tomorrow.

Where will I find the vent pipe?

Cheers,
BR

If you fill too much the water will come out of the vent pipe that is above the central heating header tank. I the header tank starts to overrun it will
come out of the overflow pipe outside. Sounds like your feed pipe form the header tank is blocked. But using the hosepipe will fill you up.

 

[blackrat779]

Hi Thanks again,

I will take it slow and keep checking in the loft.

Thanks for the advice at least it gets me out of trouble for a while

Cheers
BR

 

[blackrat779]

Hi guys, an update on my central heating.

I did the backfill thing and filled up the system although not to the breather. I gave up after several hours of waiting with the mains water tap to the hose full open. The upstairs radiators are all full of water though.

So I can hear the pump working and the water circulating. I can see the flame of the boiler but no hot water or heating. I can confirm that the controls are set correctly, thermostats ect. Very confused.

BR

 

[mogget]

If you waited for several hours with the tap and drain cock open, water should have been coming out everywhere, as it were.

Clearly the water wasn't getting in.

I think you might need a plumber to clear the blockage or replace pipework if you can't do it yourself.

Have you tried the magnet test?

 

[blackrat779]

Ok sounds fair. No what is the magnet test?

Thanks
BR

 

[mogget]

Take a magnet and apply it to the junction where the cold feed joins the main system. If it sticks then it's likely blocked with magnetite sludge.

What colour was the water you drained out?