Combi boiler low pressure HELP!

[Clinkers]

Hi All,

That time of the year again: I switch the heating back on and the boiler is acting up!

Only noticed today that the pressure gauge on the boiler is at nearly 0, usually up aound 1.5. When the heating came on, I could hear a noise like sand falling down a pipe from the boiler. Bled the rads: downstairs were fine, all the upstairs just keep hissing but no water comes out. They all still heat up, but not great at the bottom.

We were told when we first moved in to push down a handle in the airing cupboard to switch off the rads for summer, thats what we do, then just open it again for the winter. But every year, there's a problem with at least one rad not heating right/

The combi boiler is only in 2 years, system was flushed. Anyone have a clue WTF Im doing wrong?

Im afraid to just top up the water in the boiler: where did the other water go? Could I have a leak (looked around, under all rads is dry, no sign of leak in attic where tank is)

Any helpl appreicaited!


edit: heating on now, pressure up to .5, bottom of rads not heating fully

 

[wiz569]

The pressure will rise a bit as the heat builds up but it should be about 1-1.5 when cold,think you need to top up your system m8

 

[JimmyP]

As wiz says turn your heating off pressurise your boiler to 1 to 1.5bar then everything should be fine then,but remember if you bleed a rad remember to pressurise the boiler back up to 1 to 1.5bar

 

[sticky]

There should be a water pipe at the bottom of the boiler with a turn on tap or 2 turn one or both taps until the pressure rise to normal the should be ok

 

[JimmyP]

Your looking for the filling loop to open to repressurise the boiler

 

[ekwat]

As sticky and Jimmy say. Fill the system using the loop that should be under the boiler to increase the pressure. Running on too low a pressure is not recommended.

I don't know why you have lost pressure but I also don't know why you have a valve in the airing cupboard to turn off in summer. I fitted my own system and just don't use the central heating in the summer. There is a possibility you are getting air into the system through this valve but without knowing what it's for I can't really say.

 

[JimmyP]

Take a picture of this valve you use to shut off your heating I'm intrigued as to what it is

 

[wiz569]

Sounds like a conventional boiler to me which would explain the valve to isolate the heating during the summer months and only heat the hot water cylinder

Sent from my ZTE-BLADE using Tapatalk

 

[ekwat]

Sounds like a conventional boiler to me which would explain the valve to isolate the heating during the summer months and only heat the hot water cylinder

Sent from my ZTE-BLADE using Tapatalk

Would that system have a pressure gauge?

We need some photos.

 

[JimmyP]

The op said it was a combi boiler in his first post

 

[ekwat]

The op said it was a combi boiler in his first post

Not to offend the op, but I've read many posts where people aren't sure of their system. Hence my pressure gauge question. I'll leave the thread now.

/I did actually read the op :tongue:

 

[Clinkers]

Take a picture of this valve you use to shut off your heating I'm intrigued as to what it is

This one, m8

I just put it all the way down for the summer. Should I just turn all the rads off in future?

edit: the red thing is the compression chamber that was installed when we switched to the combi boiler, it's beside the hot water cylinder in the airing cupboard (or hot press, for wiz569!)

 

[Clinkers]

Sounds like a conventional boiler to me which would explain the valve to isolate the heating during the summer months and only heat the hot water cylinder

Sent from my ZTE-BLADE using Tapatalk

We had a Halstead piece of crap that came with the house, caused no end of trouble. Got a new condenser boile (combi?) 2 years back, I know its a condenser cos the condensate pipe froze on me last crimbo eve, and it the guys here who helped me get it sorted! Maybe thats why i have the lever there, it's left over from the old convnentional sytem.

I dont see any pipe to fill it at the bottom of the boiler, but I know there is a valve in the attic that I can do it from. I'll have a pop tomorow when the kids arent asleep. Just hoping there isnt a leak, even though I cant see one.



You can just see the gauge here, its just over 0, goes to .5 when heating is on

Thanks for all the quick replys!

 

[Clinkers]

Not to offend the op, but I've read many posts where people aren't sure of their system. Hence my pressure gauge question. I'll leave the thread now.

/I did actually read the op :tongue:

No offence taken m8, I'll take all the help I can get!:Biggrin2:

 

[ekwat]

That may be a condensing boiler, hence the condensate pipe but it's not a combi boiler ( or at least it's not working as a combi ). Firstly, you have a hot water cylinder, which wouldn't be there in a combi system and also, looking at your pipework, you have a gas feed in and a hot water loop in/out. If it was a combi you would have the water loop for the heating and a cold feed in and hot water out for the hot water.

As far as I remember, you have a vented system and in this case the system wouldn't be pressurised to the same extent as a combi system. The valve you turn off doesn't really need to be turned off in the summer assuming the diverter valve is functioning correctly.

As for the rad problem, try bleeding them for a few days and see if anything changes.

Also, in the attic do you have 2 tanks? You should have 1 big one that feeds your hot water cylinder and a smaller one that feeds the heating system. Check the water level in the smaller tank and the function of the ball cock.

 

[liambalfour]

also if the bottom of the rads dont heat up you may have limescale in them and need a flush