bleeding daily

[sooey]

softus the point is if the water level is too high, fresh water is introduced, bringing excess air in with it. I don't know if this would be the cause of the ops problems, I was just answering your query as to how a high level of water in the f&e could lead to air in the system. ray

 

[Softus]

softus the point is if the water level is too high, fresh water is introduced, bringing excess air in with it.

I know that was your point, and I thought I'd responded with clear and concise reasoning that explains the flaws in your point.

Until you have more information about your theory, or some basis for disagreeing with my explanation, I can't agree that you've successfully thought of a way whereby air is introduced.

 

[diy_dude]

In my case I can confirm that no water has left the tank via the overflow / warning pipe. The currently level when the system is hot is a long way below the outlet as can be seen in the photo.

Is there a suggested way to collect the 'air' that is bled from a radiator to see if it is hydrogen. I am aware that hydrogen will pop in contact with a match.

Still trying to determine where this 'air' is coming from.

I am really puzzled by one fact:
We have the heating on for two hours a day, 1 in the morning, 1 in the evening. Air only seems to collect in the radiator after the evening run. I have confirmed this by attempting to bleed the radiator 1 hour after the heating has gone off twice a day.

 

[sooey]

softus are you saying that introducing fresh water into a system does not bring excess air in with it? that's not what I was taught if you are. By the way it's irrelevant when in the hot/cold cycle the new water is introduced, so what does it matter when the float valve opens. diy-dude you say that your system only seems to suck air in in the evening, so what's different at that time are you heating the water then as well.

 

[Softus]

softus are you saying that introducing fresh water into a system does not bring excess air in with it?

No. If that's what I meant to convey then that's what I would have written, but I wrote something entirely different.

By the way it's irrelevant when in the hot/cold cycle the new water is introduced, so what does it matter when the float valve opens.

By the way it's far from irrelevant, and it does matter when the float valve opens, for the reason that I stated. If you disagree with my reasoning then it would be helkful if you would point out my error, rather than just blandly contradicting my conclusion without giving any explanation.

 

[sooey]

softus you asked how a high water level in the f&e tank would lead to air in the system, I pointed out that this would introduce fresh water and explained why, you argued against this being valid but you seem to accept that fresh water being introduced constantly into a system will bring excess air in with it. I know that you are a man who likes a good argument, but I can't see where you're coming from on this one. A little less of the condescending headmasterly thing wouldn't go amiss though

 

[Softus]

softus you asked how a high water level in the f&e tank would lead to air in the system

I didn't agree with your conclusion, but was open-minded enough to consider that I might be wrong, hence I asked for your reasoning.

I pointed out that this would introduce fresh water and explained why

You did, but your reasoning was wrong, which makes your conclusion wrong. How can you not see that?

you argued against this being valid but you seem to accept that fresh water being introduced constantly into a system will bring excess air in with it.

All you're doing is repeating the same conclusion, and taking my tacit agreement that fresh water contains more oxygen in a poor attempt to prove that you're right.

I know that you are a man who likes a good argument

I do, but this one doesn't qualify as good. Yet.

...but I can't see where you're coming from on this one. A little less of the condescending headmasterly thing wouldn't go amiss though

If the cap fits then wear it - the only thing I'm saying is that you're (a) wrong and (b) not thinking clearly. If you feel like a scolded scholar then this says more about your schooldays than anything about my manner.

So, if you really believe that anything about the following statements is wrong:

I can see a few flaws in your reasoning, viz:

1. The float valve, in your scenario, wouldn't open until the system cools, so any fresh water in the cistern won't be drawn into the system until the cooling cycle after one in which it was admitted to the cistern.

2. Given point 1 above, I expect that any fresh water drawn into the cistern will contain no more oxygen (whether free or otherwise) than water that had been sitting in the cistern a long time (e.g. months).

3. Notwithstanding point 2 above, if any more-than-averagely-oxygenated water did enter the system, it wouldn't immediately appear as bubbles in a radiator - it would be rather more likely to accelerate the corrosion in the radiators, releasing Hydrogen as one of the usual suspects in source of the corrosive reaction. If this has happened, then the action you need to take is the same as if the system were sludged up.

...then why don't you just explain which parts are wrong?

 

[Softus]

Is there a suggested way to collect the 'air' that is bled from a radiator to see if it is hydrogen. I am aware that hydrogen will pop in contact with a match.

Sod all that - just drain the system and flush it out.

If it turns out that I'm wrong then at least you'll have eliminated one possible cause for the cost of a dose of inhibitor, and the investigation will have moved forwards.

 

[sooey]

remember I posted my reply to your direct question which was how would a high water level introduce air into a c/h system? I'll go through it again, ballvalve badly adjusted causing water level to be too high when system cold, as system heats up water expands back into already full f&e and overflows. System cools so water contracts, level in f&e cistern now falls allowing badly adjusted ballvalve to release more water until f&e is full again, system warms up again and starts whole cycle afresh and so on ad infinitum. In other words your point one is irrelevant as you asked how air would be introduced not when, point two is nonsensical to me because in a well set up system the only water to be exposed to air is the surface water in the f&e which would just rise and fall gently with normal expansion and contraction and not be too disturbed, leading to minimal aeration,
whereas once the ballvalve opens water pours in bringing excess air with it and churning up the water already in the tank and aerating it as well. point three I don't follow your reasoning on, if enough air was getting into the system and the water was being ciculated around by the pump, why wouldn't the air manifest itself in the radiators?

 

[Softus]

<duplicated post removed>

 

[Softus]

remember I posted my reply to your direct question which was how would a high water level introduce air into a c/h system?

Yes; I remember - your answer was as follows:

I believe it's because if the level is set too high with the system cold (ballvalve adjustment), then when the system heats up, the water will expand into the already full tank and out of the overflow, causing the ballvalve to open. As the water contracts again on cooling, this then introduces freshly oxygenated water into the system.

I'll go through it again, ballvalve badly adjusted causing water level to be too high when system cold, as system heats up water expands back into already full f&e and overflows. System cools so water contracts, level in f&e cistern now falls allowing badly adjusted ballvalve to release more water until f&e is full again

No. This isn't what you wrote - please see above.

...system warms up again and starts whole cycle afresh and so on ad infinitum. In other words your point one is irrelevant as you asked how air would be introduced not when

True - that is what I asked, and you answered. My first point was relevant, because it was made in the context of this topic, in an attempt to move the discussion on, not to remain bogged down in the same tedious meta-argument like you're doing.

point two is nonsensical to me because in a well set up system the only water to be exposed to air is the surface water in the f&e which would just rise and fall gently with normal expansion and contraction and not be too disturbed, leading to minimal aeration, whereas once the ballvalve opens water pours in bringing excess air with it and churning up the water already in the tank and aerating it as well. point three I don't follow your reasoning on, if enough air was getting into the system and the water was being ciculated around by the pump, why wouldn't the air manifest itself in the radiators?

Because, as I've already explained (but you seem incapable of understanding), the water would lie in the cistern between the CH on periods, giving time for any extra air/oxygen to dissipate.

JHC.

 

[sooey]

if you read the meaning in my first post and my last I think that any reasonable minded person would agree that they are the same, it was you who started this "tedious meta-argument" not me, all I did was give you an answer to a question that you had posed. you may well have explained that the water would lie in the f&e cistern long enough to dissipate the excess air, but I disagree. For a start as soon as the water begins to contract back into the system the ballvalve opens and pours water into the cistern, this does not lie on the surface of the f&e but displaces the water there and plunges into the depths of the cistern, from where some of it will be scked down into the system and circulated by the pump. is that clear enough for you now or shall I draw you a picture.

 

[Softus]

if you read the meaning in my first post and my last I think that any reasonable minded person would agree that they are the same, it was you who started this "tedious meta-argument" not me, all I did was give you an answer to a question that you had posed.

Did you, or did you not, post your theory about the water level in the context of this topic? Or was it just a coincidence that it appeared to have some relevance to the OP's problem?

you may well have explained that the water would lie in the f&e cistern long enough to dissipate the excess air, but I disagree.

I can live with that - we'll have to agree to disagree then.

For a start as soon as the water begins to contract back into the system the ballvalve opens and pours water into the cistern

You have no factual basis for believing this is what's happening here, because you don't know how high the float arm is set.

shall I draw you a picture.

No picture necessary - feel free to b*gger off though.

 

[sooey]

softarse I think its you who should bugger off on this one you've had the answer to the question that you asked, and you've had it fully explained to you (it's hardly rocket science now is it) , whether it's relevant to the ops query is a different matter entirely.

 

[Softus]

softarse

Oh how original - it was only a matter of time before you used that well-worn term.

you've had the answer to the question that you asked

My point exactly, and your explanation doesn't hold water (pun intended).

whether it's relevant to the ops query is a different matter entirely.

Yes it is. So was your original point relevant, or irrelevant? No need to answer - this is firmly rhetorical.