F & E tank overflowing with WARM water.

[ukdood]

Hello all,

My F & E tank was overflowing quite a lot before Christmas so I installed a new plastic type float valve (vertical type) which stopped the problem for a week or so. I installed a good old ball type float valve & this again stopped the problem until this week when I noticed again a trickle of water from the overflow pipe outside. When checking the tank in the loft the water is warm & the float valve is almost under water, when the heating pump stops water comes from the expansion pipe for about a second or so ( I guess this is why the water is warm!) There also seems to be a lot of air in the system as lots of gurgling noises from one of the downstairs radiators most mornings, I bleed the system & then the air gets back in after a couple of days!

Any ideas?

Thanks in advance

 

[caterhamplumbing]

This is a term called pumping over. This normally is caused by a blockage of some kind. In my experience this is generally a blocked cold feed.
But from your discription it sounds more like the system is drawing in air when the pump is running, and when it stops the air rises to the top of the system and comes out of the vent, pushing out some water as it goes.

This can be caused by the pump itself being set too high or the configuration of the open vent and cold feed.

What is the pump set on?

If you trace the flow pipe from the boiler does the vent pipe tee in before the feed, and are both before the pump.

 

[ukdood]

Hello & thanks for the early reply.

The pump was on speed setting 3 (Grundfos) which I have now lowered to 2, the vent comes of about 3 inches before the feed before the pump. I have bent the float valve to make the water level much lower in the f & e tank & turned the boiler down to about 3/4 power.

After doing the above I asked the wife to turn the thermostst down (they do have uses)while I checked the vent which a bit of water still shot out?

I have taken pictures but dont know how to post them?

Thanks in advance[/img]

 

[ukdood]

The system is now nice & quiet (this morning) & no signs of water coming from the overflow! will check again tonight.

Thankyou very much for your help, it is very much appreciated.