Open vented heating system - Draining it Down?

[First-time-buyer]

How long should it take to drain down an open-vented heating system?

6 radiators. 3 upstairs, 3 downstairs. Drain valve on the lower rad, which piped via the concrete flooring.

 

[footprints]

Varies but 20 to 30 mins at most. Some drain quicker.

 

[First-time-buyer]

2hrs and a bit later... still going..

Would a slow draining system indicate that the system needs a Power-Flush due to Sludge/Blockage?

I could throw in some X400, and run during the winter period..

 

[footprints]

Assuming your tank in the loft is not refilling, all your rad valves are open and you are opening the air vents on the radiators as the level drops, the only other likely reasons are blockage, or the drain valve is not opening fully.
Often the washer pulls off the end of the plug and so you are only draining through the small hole in the middle of the washer.

 

[First-time-buyer]

Ah...... I see...

All rads get hot, so don't suspect a blockage...

Thankyou..

 

[PotatoHead]

You might find the rubber washer's stuck on the drain off valve so it's only draining very slowly. If it is stuck the only way to get it off is jamming a screwdriver or similar into the valve from the end you undo and dislodging it - trying to catch the water that goes everywhere.

 

[footprints]

I was waiting to see if you came back to say the washer was stuck however before you start.
If so that’s where the fun begins, requires nerve, lots of plastic sheets, old towels under the drain valve and a bit of luck.
Then completely remove the plug and try to grab the washer with pointed pliers, pull out and slam the plug back in quick!

 

[First-time-buyer]

You are all Right...

Just unscrewed the drain plug right out, the rubber washer is currently stuck in the hole, and not on the end of the drain plug.

and I am not going to pull it out right now...

 

[First-time-buyer]

Does the rubber washer push on?

Is it easier to replace it?

Its a 1/2" Old Skool Drain valve..

 

[footprints]

Yes they are a standard size on drain cocks, either buy some on a card from your plumbing supplier or swap one off a new valve.

 

[kbdiy]

And don't overtighten when you replace it. Only just needs nipping up to stop the flow. Overtightening just compresses the washer and causes the problem you have now.

 

[First-time-buyer]

Hi all,

Advice has been 100% spot on so far, Thanks awarded.

This is the bad boy that's fitted to the rad, I can feel the rubber seal inside the valve when I have unscrewed it fully. The tiny hole will explain why it takes 50yrs to drain down, and we know the solution.

I could just replace the screw in piece, however its one of these and I cant seem to find just 1. I can pick them up from eBay in a pack of 5..

The plan is to throw in some sludge remover / de-scaler as the boiler is kettling... then remove it once the winter spell has moved on.. I could replace it then..

 

[footprints]

http://www.screwfix.com/p/drain-cock-type-a-heavy-pattern/96725

This will do, the difference between heavy and light pattern is that the heavy has the extra ring to stop the plug coming out if opened too far, and some have the washer held on with a nut instead of just pushed on The washers should be the same though. Or just ask in any Plumbase, Grahams, or independent plumbers merchants. Several on a card for peanuts.

Or just treat yourself to a selection kit like the one towards the end of the page (Part 12611) then you can save yourself grief the next time a tap gives up!

http://www.bes.co.uk/products/094.asp