Air leak, Honeywell Valve

[neilleeds]

Hi,

I am having a problem with air in my open-vented central heating system. I checked out the Honeywell mid-pos valve and it appeared to have been weeping so I guess it is this that is introducing air. Having tightened the nuts a bit it doesn't appear to be weeping now but it seems like air is still getting in.

The symptons are:

Slight bubble occasionally in radiators, usually when boiler turns off and pump stays on, also on cold startup.

When valve moves to HW mode there is an audible and random clicking noise which sounds like air bubbles through valve (valve is quiet on CH mode).


1. The valve is after the pump, could this still introduce air (seen references to it when on the low-pressure side)?

2. If it doesn't appear to be leaking water, could it still be introducing air?

Many thanks to anyone who can help.

Neil

 

[45yearsagasman]

It's extremely unlikely that air is getting in via that valve as its just after the pump.More likely to be a blockage around cold feed/open vent connections.The use of a magnet will detect magnetite in copper pipes.

 

[neilleeds]

Thanks,

There were deposits in the header tank which I carefully cleaned out recently, since then there has been no further deposits but could these point to the same problem?

I will look for a blockage in the pipes (plastic).

I put a cup of water up to the expansion pipe to see if it was drawing in air and when the system fired up, the water level dropped a bit but then rose back up to the start level. I presumed this was ok. I turned the pump to speed 2 anyway just to be sure but it didn't help.

 

[neilleeds]

I have discovered that several of the lockshield valves downstairs appear to be leaking, I suppose this is the likely cause of the air?

What is the best way to remedy this? Replacing them presumably means a drain down, I would prefer to do this when the weather is a bit warmer. Any temporary fixes?

Thanks

Neil

 

[Boilerman2]

Make sure that your circulating water is treated with Fernox F1 or Sentinel X100 Inhibitor as Hydrogen gas is often mistaken as air in the system!

 

[neilleeds]

Make sure that your circulating water is treated with Fernox F1 or Sentinel X100 Inhibitor as Hydrogen gas is often mistaken as air in the system!

Thanks, I tried to light it but it didn't seem to ignite. I assume the system is treated but I don't know what with so I can't top it up. I'm planning to do a drain-down and flush etc maybe in a few months and I will then put some X100 in (and put the sticker on the tank!). I might conduct the nail test to verify the existence of inhibitor.

 

[neilleeds]

For anyone interested, it appears that the boiler has been kettling, causing the air. Turning the boiler stat down and pump up seems to have helped. I'm planning on putting some X400 in for around a month and then a good flush followed by X100 and maybe X200. Hopefully this will restore the system to full health.

Thanks for everyones help.

 

[Agile]

Why do you believe that kettling will produce air?

Its normal for a pump to be run on"2".

Tony

 

[neilleeds]

Why do you believe that kettling will produce air?

Its normal for a pump to be run on"2".

Tony

From what I read I believed that the kettling was boiling of the water which produced air bubbles. Are there any other obvious things it might be, since it seemed better with the pump turned up I guess that rules out air being drawn down vent. There is a fizz noise at one of the radiators when the boiler turns off and the pump is still running which dies off after a minute or two.

Thanks

 

[Agile]

When water is boiled it produces, WATER VAPOUR !

Water is H2O and air is N2 and O2.

I suggest you see whats fizzing!

Tony

 

[neilleeds]

When water is boiled it produces, WATER VAPOUR !

Water is H2O and air is N2 and O2.

I suggest you see whats fizzing!

Tony

What is the best way to do that? I presume it is coming from the boiler and is caused by scale. Thanks

 

[Agile]

There is a fizz noise at one of the radiators when the boiler turns off and the pump is still running which dies off after a minute or two.

Thanks

You said the noise was at a rad!

I have not been to your home so all that I know is what you tell me.

Now you say the noise is at the boiler?

Tony

 

[neilleeds]

There is a fizz noise at one of the radiators when the boiler turns off and the pump is still running which dies off after a minute or two.

Thanks

You said the noise was at a rad!

I have not been to your home so all that I know is what you tell me.

Now you say the noise is at the boiler?

Tony

Sorry if I'm not been clear, I appreciate your help.

The noise is in the inlet of the rad which I guess (but don't know) is the one closest to the boiler on the circuit. The noise starts as soon as the boiler stops burning. There is also a (not especially loud) whistle noise from the boiler at higher temps/lower pump speeds. I have had air (or something) accumulating recently and glugging in our bedroom rad on morning switch-on. It was silent this morning after turning the pump speed up and the boiler stat down.

Thanks

 

[Agile]

If a joint is sucking in air that can often be seen if you put something like shaving cream around the joint.

I cannot think of any cause for the noise apart from pipe contracton noise though.

Tony

 

[neilleeds]

If a joint is sucking in air that can often be seen if you put something like shaving cream around the joint.

I cannot think of any cause for the noise apart from pipe contracton noise though.

Tony

Ok thanks I'll try that.

I think the system could do with a good clean, flush and inhibit (think the inhibitor could do with renewal and I have no idea what is in it). Bearing this in mind I might as well put in some X400 now and see if this helps with any of these symptoms. Then I have a month to see If I am happy with the system before a flush and inhibit (and maybe change a few rad valves as well).

Does that sound sensible?