As all radiators get hot very quickly it is something I have not tried
Central Heating Open vented - Air problem
- Thread starter nairb999
- Start date
As all radiators get hot very quickly it is something I have not tried
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I am extremely grateful to all who have put forward suggestions which have been many. My problem is down to somehow air being sucked into the system. I have modified piping which has not improved things. I have cleaned system twice. So at a loss on best way forward. There are no evident leaks
Some more information that may help. I have noticed that with the pump running if I place my finger on the cold feed/expansion outlet in the expansion tank there is a high degree of suction. Is this correct ?
Some more information that may help. I have noticed that with the pump running if I place my finger on the cold feed/expansion outlet in the expansion tank there is a high degree of suction. Is this correct ?
Sorry if this is a bit jumbled, but I've been reading your posts again.
What happens if you remove all the tops from the TRVs, so they do not operate?
You need to fit a room stat.
Do you have any way of measuring the flow and return temperatures at the boiler, e.g a contact or infrared thermometer? With the boiler stat set to max they should read 82°C and 71°C.
You could also try an Aerjec, but it must be installed as per the instructions as the orientation is critical to correct working.
If you do not have a room stat the boiler will continue cycling on and off, even if all the TRVs have closed down. In this situation the pressure in the system will rise and could give rise to noise in the pipes.nairb999 said:
What happens if you remove all the tops from the TRVs, so they do not operate?
You need to fit a room stat.
Do you have any way of measuring the flow and return temperatures at the boiler, e.g a contact or infrared thermometer? With the boiler stat set to max they should read 82°C and 71°C.
Presume you mean the outlet which is under water at the bottom of the F/E tank. The cold feed is the neutral point so there should not be any suction there. Is the F/E tank continually filling up?
Some say (e.g. Danfoss) that the correct order should be: cold feed; open vent; pump.DP said:
You could also try an Aerjec, but it must be installed as per the instructions as the orientation is critical to correct working.
no difference - in fact I have run the system with only one radiator operating and it runs quieter ie the less time the boiler is on the quieter the system runs
I don't but will make some enquiries if it could assist
Correct and I feel this is where my problem lies but can't understand why if the system is correctly piped
I have thought about this as a solution - is it possible you could sketch me a layout based on my configuration if you feel that is the best solution
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You said, if I remember correctly, that the problem only occurs when the boiler is hot. Have you tried turning the boiler thermostat down a bit and seeing what happens? Can you get a setting where there is no noise?
I was thinking that maybe the pump is not properly sized for the boiler and the number of rads. If you cannot achieve the 11 degree difference at the boiler, it's probably because the pump is too small
Does that answer apply to this question as well
Here are the Aerjec Instructions
One of the options in Diagram 4 is the one to follow. The Aerjec must be installed with the vent at the top as shown in the diagram. It will need some plumbing changes, but I'm sure you can work that out. [/url]
why not just combine the feed and vent as i suggested before, take 30mins to do it temporary with a couple of compressions just to test it. Usually works..
All in all, I would combine feed&vent into an air seperator, similar to what DH has suggested but with only the vent pipe connection, and then stick some x400 round the system to get on top of any corrosion issues. job done.
All in all, I would combine feed&vent into an air seperator, similar to what DH has suggested but with only the vent pipe connection, and then stick some x400 round the system to get on top of any corrosion issues. job done.
Many thanks again for your assistance. On your previous suggestion you intimated that this would work if air is being drawn down the vent pipe. Other than when the pump kicks in and there is suction for a second there is much more suction on the feed hence my search for possible other solutions.
indeed I did, and its very possible it will. Certainly won't do any harm and won't cost you very much, bar a few fittings and your time. Providing there are no other obvious reasons for your problem then this is what I would do.
That's diagram 5 in the Aerjec Instructions.
More responses to DH
Reduced noise but on a very low setting
No only what you would expect due to expansion
Reduced noise but on a very low setting
No only what you would expect due to expansion
I was warming to this suggestion before reading the attached note in the leaflet
The cold feed and vent should not be combined into one
pipe before entering the Aerjec as this may slow or stop water
entering the system during the initial fill or subsequent
de-aeration.[/b]
Don't worry, this is reffering to a system where there is basically just a 22mm cold feed and no vent pipe as opposed to a "combined" vent&feed, ie joined together. Seen it done in new builds, and is indeed a nuisance to fill up.
Thankyou for clearing that up. So I could initially try combined vent & feed and if no improvement leave as is and fit air seperator which would be a simpler job
After spending so much time on system cleaning and piping modifications I did some research on system balancing and after several weeks of trial and error ie tweaking lockshield valves - on some radiators an awful lot I have got a resolution to the problem. I never thought this was an issue as all radiators did get hot in a relatively short amount of time but now they all get hot at about the same rate with no excessive system noises and no air in the system
Many thanks D Hailsham - a simple resolution without further expenditure
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