help! Lost Pressure!

DARYALS

Hi,

I need help, I have just taken off three radiators for some plastering work. These have now been put back on again. My central heating now has no pressure which is what I thought would happen. I have checked that all the radiators are properly hooked up, and they are. I have also checked for air in the system on several occasions and it appears to be free from air. I have a BAXI combi boiler. I have tried getting everything to get the pressure to raise from zero bar but nothing! The water is piping hot, but the radiators are luke warm, any help??

Thanks

the_dead_parrot

Hi there, so when you turn open the port to let the cold mains pressure into the boiler (which thus makes the arrow on the gauge rise) nothing happens?

does it make a filling up noise? whooshing water etc?

is there water leaking from the blowoff pipe which would be situated from the boiler leading to an outside wall of the property?

If it is not raising the pressure but it is making a noise indicating water movement then it sounds like the water is trying to repressurise the boiler and system but is being lost somewhere...

edit... alos just a few things... do you have thermostat radiator valves, or just normal manual type? if so are both ends open on all rads?

make sure all the bleeds are closed on the rads... obviosuly if you take 3 rads of there will be a bit of air, depending on whether you drained the whole system or just shut the valves off on both sides.

what model is the boiler baxi 105e?

if you can answer these then hopefully I can help a little more

DARYALS

I have what appears to be 4 ports. One controls the hot water, when you switch this one to the right I get no hor water. The other three have some signs on them, I'll try and explain.

Switch one - Far left of the boiler has an arrow pointing down and a raidiator
Switch two - Controls the hot water, this has a gas sign next to it
Switch three - Far right, has a arrow pointing up and a radiator next to it.

When the boiler is switched on then it makes a filling up noise.

There is no water leaking from the blow off pipe, I only took the radiators off two days ago and things were fine!!

I think that the boiler is trying to repressurise as there is water movement. However I have tried leaving the boiler on for 10 minutes at a time and still no movement of the pressure line??

hope this helps!!

the_dead_parrot

Switch one - This is the flow to your radiators
Switch two - Sounds like the water going to your hot tap pipe
Switch three -return pipe from your radiators

Right so you switch the boiler on, which means it tries to come on as normal the pump will run etc so whatever water is left in the system it will try to circulate...

you need to manually put pressure in the boiler... the two pipes flow and return i mentioned for central heating, do either of them have a smaller pipe connecting onto them with a screwdriver slot valve or a hand turning valve?

The boiler will not repressurise itself no matter how long you leave it on for, it gets its pressure from the cold mains (which is where the pipe connects onto the flow and return with some form of valve to stop and start repressurising flow) this cold mains pipe also goes into the boiler and is heated and tunred into your hot water which comes out another pipe and goes to your hot tap.. so there are your 4 pipes...

the ch flow and return should be bigger pipes of around 22mm in size... the cold going onto them should be smaller around 15mm...

DARYALS

OK, there do seem to be two smaller pipes and at the base of one of the pipes there is a what appear to be a small blue turning valve, when the valve is removed there is a phillips screw under it, is this what I'm looking for? There seems to be two small 15mm pipes (or what appear to be them), but I can see no other valves as such!

DARYALS

Sorry! The model is Baxi 105e

the_dead_parrot

thats sounds like what you are looking for... obviosuly its hard for me to visualise it, does the smaller pipe with the blue valve connect onto a central heating 22mm pipe?

basically by turning it you are allowing some of the mains water pressure into your central heating, and then shutting it off once thr 1-1.5bar level is reached... give it a go

you will have to fill it up to that level, then go and check that there is no air in the radiators with a bleed key... once all the air is removed, top the pressure back upto 1-1.5 and then turn the boiler on, it will probably sound a little noisy for a few minutes while it circulates to get the air out... which it will do on its own as it has a built in automatic air vent... so the pressure may have to be topped up a tiny bit again

hope that helps

DARYALS

The boiler is making really bigger noises and the pressure bar is now upto three and it sounds like its struggling BIG time, any ideas, it keeps making a knocking sound?

the_dead_parrot

right you have kept this valve open for too long, it should be open for a short time until it reaches the 1-1.5 level and then turned into the closed position...

if not it will continue to allow mains water pressure into the boiler... which once it reaches 3 it releases the water from the blowoff valve (and to the outside pipe) and that is the banging noise you are experiencing...

close it off the valve should then continue to release the water until it gets down the an acceptable level... then you can start doing the radiarot air checks as i mentioned in the last post...

at least you have found the filling valve though

DARYALS

I actually turned my water supply off which did the trick! I will turn the water back on and try to tighten the the screw, hopefully this will bring the pressure down to 1-1.5. OK, will be a few minutes and I'll give you an update!

the_dead_parrot

it is the blue bit which needs to be turned the screw just holds the blue part on if it is the same valve I am thinking of... take the scre out, put the blue part on, it should fit on to a little rectangle shape, and then that can be turned by hand to allow the water to stop or start...

hope that helps