Why do i have to fill the system to have a shower?

[joeread]

I have a condensing combi boiler, when there is no pressure on the gauge i am not able to get hot water from my shower, when i fill using the filling loop the hot water comes back,

i thought the filling loop was for the central heating only?? why do i not get hot water when the presure is down???

thanks

 

[Agile]

Its the same basic boiler and it needs the usual pressure whatever its doing.

 

[JohnD]

you need to find the leak and repair it.

 

[joinerjohn]

As John D says, There must be a leak on your central heating system. How long does the pressure last when you refill the system to 1 bar? Usual suspects are a leaky joint to a radiator, leaking joint somewhere on the system, leaking heat exchanger, or a leaking pressure relief valve (usually this is built into the combi)
I'd reckon having a look round your radiators and see if you can find a leak. Failing that, get a gassafe reg plumber in to have a look.

 

[Whitespirit66]

And when you find the leak, get some corrosion inhibitor put in the system. If you have been regularly topping up, then the inhibitor will probably be non-existant, and your radiators will soon crumble to dust!