flushing a central heating system

[John Kelly]

I want to flush my central heating system as the boiler sounds like a jet taking off when it's heating the house - okay on the water funnily enough. I want to drain it a few times till the water's clear, then fill it with some chemical flusher stuff for a week, then drain it again and refill it with the proper inhibitor stuff.

My problem is that there are three radiators upstairs which can't be bled. The bleeding valve is stuck. I don't particularly want to replace the radiators as I can't get any the same size. What are my options?

Thanks

[daddyfreddy]

Why not just replace the bleeding valves?

If you do want to change radiators without altering the width of the pipework you can buy extendable radiator valves which will accomodate a slightly smaller radiator replacement.

[EricP]

Replace the faulty valve at the same time as draining.

Get an assistant as gopher, several bowls/trays that will fit under the pipe by the valve.

Use a small hacksaw to nick the underneath of the pipe until the water flows out but you can stop it with your finger.

Fill the bowls until the flow stops. The gopher does the emptying.

[sPoNiX]

I think the OP means that the bleed screw in the top ofthe rad is stuck solid.

I'd spray the drain screw with Plusgas a few days before draining the system. I'd then (attempt) to remove the screw with a *decent* brass radiator key and a pair of molegrips, taking care to undo it the correct way.

sponix

[John Kelly]

Yes that's what I mean. I'll give it a go. The radiators are fine in all other respects and luckily (when the bleeding valve worked) there was never any air to get out of them anyway.

Thanks

[John Rumm]

Have a look at product code 6918 on

example.

[Harry Bloomfield]

John Kelly explained :

Get hold a good quality bleed valve key. Drain the water down a few inches in the three radiators and put some heat on the bleed screw (blow lamp/hot air gun), alternated with a cold damp rag to help free it. Some bleed screws are mounted in a removable socket - remove the entire socket and replace with new.

[John Stumbles]

Or DIY: a 1/2" BSP x 15mm compression Chromed coupler plus a bit of 15mm Chromed tube will allow you to make an arbitrary-size extension tail piece which looks quite decent.

[John Kelly]

Good advice - my standard grey key broke just 10 minutes ago :-(