M
mightyoakbob
Hi,
I'm new here and I would be grateful for some advice if you can spare the time.
I have a Y plan heating system which did not have a problem before a recent boiler replacement but now is constantly filling with air.
In the loft there are two header tanks one for the hot water and the other for the CH system. Below that, in the airing cupboard is the hot water cylinder and the 3 port motorized valve and manual air vents on the flow and return pipes.
The boiler is a floor below the the airing cupboard at ground level but it is not vertically under the airing cupboard but displaced to the back wall of the house and has about 12 feet of horizontal pipework under the bedroom floor to connect to it. There are four pipes that make this run; flow, return, expansion and cold fill from the header tank.
Before a well reputed corgi plumber fitted the new boiler, pump and magnaclean the system was fine except it used a lot of gas. Since the new boiler I have a problem with substantial amounts of air rushing around the rads etc. which have all been bled and I have to bleed the flow bleed point in the airing cupboard twice a week.
No changes were made to the system except in the cupboard that houses the boiler, the rest of the house is exactly as prior to the new boiler. Changes to pipe layout around the boiler include; maganaclean fitted in return pipe and then after the boiler although it has the same connections ie. expansion pipe the a few inches after, the cold fill pipe and then the pump the pipework is laid out differently.
Originally, the expansion pipe was completely vertical out of the boiler until it was under the bedroom floor now it is a horizontal connection to a vertical flow pipe out of the boiler.
Please correct this amateur if I'm wrong but I think there are 3 main possibilities to explain this;
1) Air is being sucked down the expansion pipe as the pumps starts to create a vacuum behind it at switch on. Perhaps the 15mm cold fill pipe cannot provide enough water quickly enough at switch on to fill the temporary vacuum and air rushes down the 22mm expansion pipe much easier.
2) There is a chemical reaction causing gases to be produced.
3) There is a poor joint somewhere which under low pressure from the pump allows air in.
I think number 1 is the most likely caused by what is obviously a much more powerful pump that was there before. Here's where I'm very unsure though, my instinct would be to fit a one way valve in the expansion pipe to prevent air coming down it. I think these are called check valves.
Is this a good idea? Can I try it, or is there some hidden danger? Do these valves have to be fitted below the water line so that they are in water and not air or could I fit it in the loft close to the header tank where it may sometimes be in air.
Am I miles away and the problem is something else entirely.
Your advice would be much appreciated.
Cheers,
Bob.
I'm new here and I would be grateful for some advice if you can spare the time.
I have a Y plan heating system which did not have a problem before a recent boiler replacement but now is constantly filling with air.
In the loft there are two header tanks one for the hot water and the other for the CH system. Below that, in the airing cupboard is the hot water cylinder and the 3 port motorized valve and manual air vents on the flow and return pipes.
The boiler is a floor below the the airing cupboard at ground level but it is not vertically under the airing cupboard but displaced to the back wall of the house and has about 12 feet of horizontal pipework under the bedroom floor to connect to it. There are four pipes that make this run; flow, return, expansion and cold fill from the header tank.
Before a well reputed corgi plumber fitted the new boiler, pump and magnaclean the system was fine except it used a lot of gas. Since the new boiler I have a problem with substantial amounts of air rushing around the rads etc. which have all been bled and I have to bleed the flow bleed point in the airing cupboard twice a week.
No changes were made to the system except in the cupboard that houses the boiler, the rest of the house is exactly as prior to the new boiler. Changes to pipe layout around the boiler include; maganaclean fitted in return pipe and then after the boiler although it has the same connections ie. expansion pipe the a few inches after, the cold fill pipe and then the pump the pipework is laid out differently.
Originally, the expansion pipe was completely vertical out of the boiler until it was under the bedroom floor now it is a horizontal connection to a vertical flow pipe out of the boiler.
Please correct this amateur if I'm wrong but I think there are 3 main possibilities to explain this;
1) Air is being sucked down the expansion pipe as the pumps starts to create a vacuum behind it at switch on. Perhaps the 15mm cold fill pipe cannot provide enough water quickly enough at switch on to fill the temporary vacuum and air rushes down the 22mm expansion pipe much easier.
2) There is a chemical reaction causing gases to be produced.
3) There is a poor joint somewhere which under low pressure from the pump allows air in.
I think number 1 is the most likely caused by what is obviously a much more powerful pump that was there before. Here's where I'm very unsure though, my instinct would be to fit a one way valve in the expansion pipe to prevent air coming down it. I think these are called check valves.
Is this a good idea? Can I try it, or is there some hidden danger? Do these valves have to be fitted below the water line so that they are in water and not air or could I fit it in the loft close to the header tank where it may sometimes be in air.
Am I miles away and the problem is something else entirely.
Your advice would be much appreciated.
Cheers,
Bob.
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