air? pressure old worcester combi boiler s25i old model

[kaz2055]

we have a worcestor combi boiler it says s25i on the casing but isnt the one that comes when i google it.
always worked fine, if we switch it on it working okay now.
the pressure dropped to below 0.5 so we did what we did before when it has happened we added water with the filler pipe whih was never removed, the pressure went up, but carried on rising, this happened once before and we solved it by removing water from the lowest radiator. but it hasnt worked this time it is now on 3.0 (start of the 'red' scale) we took water out but didnt go down much, think at one stage we took most of water out as it stopped coming out. filled it again but it still on 3. on the other side of the filler pipe is a hex. nut was told this is a bleed vavle, opened that and a little air came out, but pressure stayed the same, we were told to let water in and bleed at same time , but pressure wont drop. we have kept the heating part switched off for safety, (wasnt sure if we have to keep it on when doing everything) when we did switch one all heating worked,,hot water no problems. have bled all radiators (except one - but that goes hot uniformly so dont think there is any air in it.)
wondering if it is an air lock or something else. also dont know what the6y are or if they anything to do with it (i thought they might as i thought air rises) but on the top of the boiler is what i can only describe as washing up liquick like tops one in red one in blue

 

[kaz2055]

Hope there is someone who can give us some advice as it a bit cold at the moment

 

[mogget]

Are you saying that you overfilled the system,

or that you shut the filling valve and the pressure kept rising by itself,

or something else?

 

[petertheplumber12]

Your filling loop that you use to fill it with water should have 2 taps (isolating vales) on it they should both be opened to fill it then closed to stop filling it. The valve nearest the boiler has a non return valve on it so if both valves are closed and the filling loop is removed completely no water can get in boiler and re pressurise it. carefully remove filling loop to make sure it is shut off properly, release pressure from a rad and it should be ok. That is why the filling loop should be removed after filling, to make sure boiler pressure stays at 1 bar only. If the filling loop removed makes the boiler leak water it needs a new filling loop complete with non return valve.

 

[kaz2055]

Your filling loop that you use to fill it with water should have 2 taps (isolating vales) on it they should both be opened to fill it then closed to stop filling it. The valve nearest the boiler has a non return valve on it so if both valves are closed and the filling loop is removed completely no water can get in boiler and re pressurise it. carefully remove filling loop to make sure it is shut off properly, release pressure from a rad and it should be ok. That is why the filling loop should be removed after filling, to make sure boiler pressure stays at 1 bar only. If the filling loop removed makes the boiler leak water it needs a new filling loop complete with non return valve.

On one side of the loop is a hex. shaped nut and on the other is the nut to add water (it did have a blue plastic thing on it but it snapped off a cple of years ago.) so is it simple to remove? am normaly okay with ordinary pluming like fitting bathroom suite or sink it just i dont always know the technical names for some things, but tbh dont know alot about boilers.
have just turned the heating part off and just using the hot water at the moment, cant afford to get BG out at the moment. the pressure is not going down now at all, drained water out the lowest radiator but after reading some of the bits on other queries they saying an upstairs rad, so perhaps thats where i am going wrong, everything works when turned on but dont want to damage it so suffering with the cold at the moment.

 

[mogget]

If the knob has broken off, your filling loop may be stuck open - can you turn the shaft with a pair of pliers to shut it off? I should point out that I don't know your boiler so I hope this isn't useless advice.

If you can close the filling loop, the pressure should drop if you bleed some water off. You should have 1 - 1.5 bar in there when cold.

Could you post a photo?

 

[petertheplumber12]

You don't need BG if you have no contract with them it is cheaper to get a private gas safe chap go to this site:- http://www.gassaferegister.co.uk/ Type in your post code and choose someone from your area, phone them and see who can come for no call out fee. As Mogget says try with a pair of pliers that should work. If you can turn the water of with pliers you are allowed to replace the filling loop you don't need to be gas safe reg for that.

 

[kaz2055]

thanks for that, yes we have turned the water on and off, (the plastic thing fell off a good while ago.
is it best to take the water on the highest radiator (thinking of any air in syetem) or the lowest one (which we have been doing with no effect) will go take a pic in a minute

 

[petertheplumber12]

thanks for that, yes we have turned the water on and off, (the plastic thing fell off a good while ago.
is it best to take the water on the highest radiator (thinking of any air in syetem) or the lowest one (which we have been doing with no effect) will go take a pic in a minute

Any rad will do, if you have a drain valve you may be able to do it from there easier if it is not a soldered one that stick closed when heated up.

 

[mogget]

As far as lowering the pressure goes, take the water from the most convenient radiator.

If the pressure keeps rising it can mean only one of two things: 1) The filling loop is passing or 2) there is a hole in the plate heat exchanger, assuming this boiler has one (I don't know for sure, maybe someone can let us know?).

EDIT - looks like our posts crossed, Peter.

 

[kaz2055]

have taken pics of the boiler and uploaded them to see if they help.
not sure how to put them so you can see but have clicked 'show my images' presume thats it

 

[mogget]

Is that filling loop valve still open? The slot should be across the pipe for closed, in line with the pipe for open. I can't see clearly from the photo.

If the valve is closed you should be able to unscrew the flexi filling hose without water p*ssing everywhere. Try unscrewing the flexi filling hose before you let the pressure off at a radiator.

If the pressure still keeps rising after you unscrew it, then the plate heat exchanger has gone.

 

[kaz2055]

thanks for your help, will have a good look again in the morning, too late to do it now, hope we can get it sorted, not a great time for no heating.
will let you know how we get on

 

[kaz2055]

Just doublechecked the nut on the feed pipe doesnt have any line - the plastic key fell off long time ago, so we marked the nurt and above it so we knew where it should bé. Will try taking it off in. Morning