Sucking in air

[wadihalfa]

Hi Folks,
I have an ordinary indirect heating and hot water system. The hot water system supplies the two upstairs rads in the bathroom and en-suite. Every morning when the hot water comes on, the two rads gurgle like mad and have to be bled everyday. I've had a new copper cylinder fitted in the last couple of months and everything else seems to be OK. Can anyone suggest where the air is being sucked into the system and how to stop it.

Thanks in advance.

 

[45yearsagasman]

If its an open system then down the open vent is the most likely place.You need to describe you system in more detail.Whats in the airing cupboard beside the cylinder? Pump/motorised valves etc.

 

[wadihalfa]

View media item 26191Hi,
Apart from the rads gurgling, a lot of noise seems to be comming from the vent thing above the pump. The pipe out the top goes to the expansion tank. Should this pipe be dry or should it have water in it?

If God had intended me to be a plumber, he would have given me webbed feet!

Cheers.

 

[seco services]

check the tank in loft has water in it.
system sounds like its low on water.

 

[wadihalfa]

The header tank is about 2 thirds full.

 

[seco services]

is water getting through ?

 

[wadihalfa]

A new hot water cylinder was fitted a couple of months ago and I took the time to flush out the CH system a couple of times and clean the header tank and add some new inhibitor.
Everything seems to work fine, the water gets hotter and quicker than it did before now I've got a new tank etc.
Its just the gurgling noise in the two rads and the air vent thing that is really irritating me.
Still, if thats all I've got to worry about these days, then I'm doing alright!

The only place I can think that the air is getting in, is via the vent pipe, but why should it be sucking air in and not pushing it out?

 

[seco services]

as i said is water getting down to the seperator etc.
just cause the tanks full don't mean the pipe is.

that amount of gurgling in the rads/seperator tell me the waters low.

 

[wadihalfa]

Hi,
We're on the edge of my plumbing knowledge now!
Can I assume the seperator is that 3-pipe thingy just above the pump?
The pipe going out the top of it goes to the header tank (sits well above the water line).
Are you saying that pipe should be full of water? At the moment it sounds like it isn't. Can it be filled by squirting water down it from the loft?

 

[45yearsagasman]

That 15mm pipe to the left of the air sep,where does that connect to? If its connected to the exp tank and at the other end connected to the return pipe(thats how it appears) then thats not right.Confirm that 1st.

 

[seco services]

Can I assume the seperator is that 3-pipe thingy just above the pump?

yes air seperator

The pipe going out the top of it goes to the header tank (sits well above the water line).

may do but the pipe splits in the loft and also go's to the bottom of the tank.
follow it down from the top and you should see a T in to base of tank that may only be 15mm as the vent is 22mm.
known as a combined feed/vent.

Are you saying that pipe should be full of water? At the moment it sounds like it isn't. Can it be filled by squirting water down it from the loft?

yes it's gravity feed so any pipes will be full to the same level as the water in the f/e tank in loft.

you can fill with water put a hose down the vent.
as i think the water from the pipe in the bottom of the tank is not getting through.

but it could be blocked down near the seperator rather than just the cold feed pipe.

you can hold a pint glass full of water under the vent pipe and turn the system on see if it sucks the water out of the glass.

 

[seco services]

That 15mm pipe to the left of the air sep,where does that connect to?

looks more like the cold mains to the loft.

 

[45yearsagasman]

That 15mm pipe to the left of the air sep,where does that connect to?

looks more like the cold mains to the loft.

Yeah you may well be right,so the 22mm from the air sep should be connected below the water line and as the tank is full enough where the hell is the air coming in?It is unlikely to be micro leaks.He's already said that the 22mm goes to the loft and "is well above the water line".

 

[wadihalfa]

Hi Guys, I appreciate the help.
The 15mm pipe on the left starts at the header tank, goes down to the airing cupboard where it goes into a 22mm T. One continues down (presumably to the boiler), the other branch to the bottom of the cylinder coil.

The 22mm pipe comming out the top of the seperator just goes straight to the header tank, no other connection.

Hope this helps.

 

[seco services]

but is it drawing air ?
i'm sure it's water not getting down to the system and the pumps probably just about covered. another few days it'll run dry.

maybe wrong.