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thescruff · Moderator Joined: 03 May 2003 Posts: 4619 Location: Bath

Back to your earlier posting.

when you open the right hand tap you have a flow, when you open the left hand tap you don't.

Do you mean the rad valves, and if so with the red valve shut and the boiler turned off, open the left valve you should get water if not you have a blocked pipe.

When you say with the red valve closed you only get flow to the right hand end is that ok, does the rad get hot.

scruff

dodders · Joined: 25 Aug 2003 Posts: 13 Location: grimsby

yeah, i meant the radiator ones.

so, to recap then; when the radiator was off, alan suggested opening the two taps to see what happened. the left hand one did nothing when the red gate valve was shut. as soon as it was open it flowed; which i guessed meant that the water was coming from the top pipe only.

so we are therefore suggesting that the bottom pipe is blocked; would this be cos it is where we drain the system so any sludge perhaps is in their?

how would i go about unblocking it?

in answer to the last question; no the radiator does not get hot with the red valve shut and flow to the right.

dodders · Joined: 25 Aug 2003 Posts: 13 Location: grimsby

ok, closed the red valve and attached my hose to the drain valve on left, heating on, opened drain valve and the right valve got hot; something that has so far failed to happen.

obviously this means we have flow in and out of the radiator, but its not going back to the system.

i checked the "screw"(?) valve next to the drain valve on the left; it has an arrow pointing back to the boiler, which to me seems correct???

so does this help with the blockage theory, or have i got my logic of flow directions all wrong??

thescruff · Moderator Joined: 03 May 2003 Posts: 4619 Location: Bath

Yes the bottom pipe is most certainly blocked.

Attach a hose to the pipe and increasing the pressure to under 3bars see if you can get water to flow out the hose, tap the pipe hard with a wooden handle or similar without denting the pipe may help to dislodge any sludge.

If that fails to clear it, attach the other end off the hose to the mains, lower the boiler pressure and try filling it through that pipe, you will have to drain the sludge back out once clear.

scruff

dodders · Joined: 25 Aug 2003 Posts: 13 Location: grimsby

thanks for the help so far, seems to be making some sense at last.

struggling at the moment to get over 2 bar, but i have had it over 4 before!! any tips to get it higher now or is it just luck.

sorry to be a pain, but could you just explain plan b in a little more detail?

where abouts exactly should i attach each end of the hose?

thescruff · Moderator Joined: 03 May 2003 Posts: 4619 Location: Bath

Don't go over 3bar the safety valve will blow.

You should be able to get some water from the drain cock at 2+ bars unless its solid, tapping the pipe along its length may free it.

is the drain cock working ok.

plan b is in your email, just reverses the flow.

scruff. Cool

dodders · Joined: 25 Aug 2003 Posts: 13 Location: grimsby

thanks for the diagrams, really good of you.

the boiler has often been over 3bar in the past, will that mean the valve has gone? how will i know and what is the significance if it has?

dodders · Joined: 25 Aug 2003 Posts: 13 Location: grimsby

the drain cock is working fine as when i turn the red gate valve on, the dog gets a good soaking!! well he likes to help!!

thescruff · Moderator Joined: 03 May 2003 Posts: 4619 Location: Bath

locate the safety valve on the boiler then trace the pipe from it to atmosphere, check the ends not capped or bunged up, you need it as part of the safety features.

You got that pipe free yet or have you decided to take the mutt swimming.

scruff Cool

dodders · Joined: 25 Aug 2003 Posts: 13 Location: grimsby

its not done yet, i think its gonna need plan b as there doesnt seem to be enough pressure there at the moment to free it. have left the spanners with the dog, but he's decided to build a go-kart instead! let you know how it goes later in the week - the blockage, not the go-kart; i'm sure that'll be fine!!