Worcester Greenstar HE - What does the siphon do?

[W4SIM]

RE:- Worcester Greenstar HE ZWB 7-30

Sorry, i know this is a pretty basic question for all the plumbers out there but what does the siphon do?

I ask as i noticed mine was leaking the other day from the bottom where it joins the pipe. It started leaking when the Central Heating came on and then stopped leaking after about 20 minutes, although the heating stayed on for a few hours after that!

Its the first time iv noticed it but my parents say its been leaking water like this for quite some time now.

So is it something that definatly needs replacing and what are the consequences of leaving it alone? I dont want all the water to rush out one day.

 

[twgas]

the siphon discharges water in a quantity, rather than a continuous dribble, to help to prevent freezing of the outlet pipe. It also makes a seal between the flue and the discharge pipe and stops gasses seeping up from drains and causing problems,it could be just a washer/seal leaking.

 

[W4SIM]

it could be just a washer/seal leaking.

Thanks, i think thats just what it is, a seal at the bottom of it.

Im guessing its not too critical to change it then?
And the siphon always seems to be full, is that also about right?

 

[RigidRaider]

Be grateful your boiler has a syphon; many older boilers that discharge in a continuous trickle have had frozen condensate pipes, which stops them working.

Yes, a syphon should be full of water a lot of the time, that's how a syphon works!

 

[twgas]

It should always have some water in it, they only discharge about half a full siphon at any one time.

 

[W4SIM]

Thanks chaps, it does seem to work properly then, just seems to leak from the bottom when the heating comes on. But atleast it doesnt need anything changing right now so il leave it till the weather gets better before attempting anything.

Thanks again.