Automtic Bleed Valve

[dannyo]

I am a plumbing novice! Can anyone advise me about an automatic bleed valve?

I have a manual bleed valve on top of the vent pipe next to my hot water tank and above my Grundfos 15-60 pump that I recenlty installed.

I am having to bleed the pump and bleed valve daily due to a build up of air.

Would an automatic bleed valve on top of the air stack pipe overcome this? I have seen air sperators advertised but know little about these?

Can anyone advise me?

 

[2face]

yes it would help greatly .. but why is it building up all the time ??

 

[dannyo]

I am not sure. I think it is becasue the new pump is not as worn as the old one which I took off?

It must be sucking air in from somewhere? Once bled the heating and hot water work perfectly?

Would the auto bleed valve be better than an air seperator?

 

[HarrogateGas]

How many rads do you have.....a 15/60 is a large domestic pump.

Auto air vents are a mythh, they cure the symptoms to a promlem but not the root cause. i be looking at why your system is getting air. is the new pump correctly installed and the head facing the correct orientation?is the pump pumping the right way round the system? is it set to the correct speed? Are the cold feed and openvent the correct configuration? is the system producing excessive amounts of hydrogen? Is the system pumping over? is Pump inertia sucking in air on start up?



These are all things you need to check before slapping an auto air vent on.

 

[dannyo]

I have 7 rads over 3 floors. I installed the pump as it was the same speed as the one I took off.

I think it is pump inertia sucking air in on start up as it works great once I bleed it. the air builds when I stop and start the pump.

I have the pump on the lowest speed and the hot water circulates well.

Is there anything I can do to prevent the pump inertia sucking air in on start up ?

I would really appreciate any advice anyone can offer me?

 

[ChrisR]

It's important to determine whether the air is being sucked down the vent pipe, or through micro-leaks in the plumbing before the pump, or is corrosion gas due to inadequate inhibitor.
Not all easy. Start by holding a tumbler of water up to the vent pipe . When the pump starts expect a pull of half a tumbler or so, but not contiuous sucking which empties the tumbler. If the vent pipe is a couple of metres + long as normal, no problem.
If you collect the gas in an upturned tumbler and it "pops" if you light it, add inhibitor. (Hydrogen gas)

 

[dannyo]

ChrisR thanks for your response.

Just a couple of questions beofre I do this test. aplogies if they obvious but I am a novice!

The vent stack pipe on my system is not curved downwards? It is straight up i.e. vertical. How would I get this into the tumbler of water?

Also you say this is typically a couple of metres long? Is this measured from the floor or from the pipe that goes into the hw tank?

I did put Fernox in the system 18 months ago however I have not put any in since changing the pump and I did drain most of the system so I will need to add some more. I just want to make sure I don't have to drain system again before I put any more in.

Once other interesting point ios that if I leave the pump running it does not get air in pump it works great, it only seems to happen when the system is switched on and off? I will try leaving it on overnight at a very low temp - will the pump run continuosly if I do this?

 

[dannyo]

Can anyone advfise me on the above as I am really desperate to get my heating going this week if possible.

Any advice would be greatly appreciated!

 

[dannyo]

I have been bleeding this valve daily as an automatic bleed valve would do and heating and hot water is working great. Purpose was to prove if an automatic bleed valve would work.

Does anyone have any comments regarding the fitting of such an item?

 

[bab]

the advice on the tumbler check was on the vent that goes over the header tank in the loft to see if there was negative pull on the vent when pump started. also see if the vent pumps over in to tank when pump stops. alot of vents dont lift high enough before bending. pumping over introduces ne oxygen into system.