Cenral heating fill tank

[delieu]

Hi,
my old gravity fed central heating system has given me a few problems since re-furbishing my bathroom especially since the addition of an in line heated towel rad. I am getting back feed from the boiler up to the filler tank!
I have noticed that the 22mm vent pipe outlet is submerged below the tank water level. Is this correct? It has been like that since the system was installed in 1968 (when the house was built), everything has been working fine untill now! Why? Advice would be much appreciated.

 

[seco services]

need more on stystem is it fully pumped etc

 

[spraggo]

The vent pipe should on no account be submerged below
the tank water level, as this will prevent air being vented to the atmosphere as well as causing the water in the water tank to be syphoned into your heating system causing corrosion.

spraggo

 

[delieu]

Thanks Spraggo, seems strange that the vent ipe has been like that since it was installed!

 

[delieu]

The outlet of the vent is only 1 to 1.5 inches above the bottom of the tank?

 

[delieu]

Would cutting the vent pipe so that it is clear of the fill level cure my problem?

 

[seco services]

should be like this.
about 450mm past water level then loop over.

 

[delieu]

Thanks Serco

 

[seco services]

Thanks Serco

thats seco

 

[delieu]

Why on earth would this vent pipe of mine been installed the way it was. It has been like that for 42 years?

 

[spraggo]

Would cutting the vent pipe so that it is clear of the fill level cure my problem?

.


Yes but the vent pipe should rise approx 450mm above the water level in the tank, before bending down to prevent water entering the tank via the vent pipe and vice versa
.

spraggo

 

[delieu]

Sorry Seco. Spelt your name wrong when replying. Many thanks for your help.

 

[delieu]

Hi Spraggo> Thanks very much for your help, but surely! If water is going to be ejected from the vent pipe into the tank, does it matter what hieght it is is above the fill level?

 

[spraggo]

Hi Spraggo> Thanks very much for your help, but surely! If water is going to be ejected from the vent pipe into the tank, does it matter what hieght it is is above the fill level?

As explained, it is to ensure that air from the heating system is vented to the atmosphere instead of into the tank water.

spraggo.

 

[seco services]

yes cause the water in that pipe is the same level before system starts and you get expansion etc its all to do with head height etc.