Hi, I live in a house with a very old CH system and boiler. The system seems to have 22mm pipes with 10mm pipes tee'd off to the radiators, therefore as I understand not a proper microbore system and also not quite conventional ie 15mm to the rads. During the winter we put the CH on constant and the HW on timed. The boiler is situated in the downstairs loo, with the tank, pump and 3 way upstairs in a bedroom cupboard. Last year I changed the 3 way valve and the circulating pump, the 3 way was completley seized, I flushed the system with some leave in chemicals for 6 weeks and then filled the system with some inhibitor added. Prior to this and still the rads in the front of the house do not get as hot as the others. I have just removed the rad from our bedroom expecting it to be really sludgy but it wasn't. The pump was running on its lowest setting, if I run it on the highest setting the cool radiators get hot, however when I do this there seems to be a problem when the hot water comes on. It is as if the pump is too powerful for the valve or the valve is too slow to operate. The pipes all start banging and clattering from anywhere between 3 and 15 seconds. Does anyone have any ideas to help me sort this out please?
Banging, Balancing & 3 way valves??
- Thread starter stoobydale
- Start date
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Bump 
. Any ideas or suggestions please
. Any ideas or suggestions pleaseBy what you've said you do have a microbore open vent system. You did the right thing by adding cleanser and inhibitor.
Setting 2 is usually a sufficient setting for the pump in an average-sized domestic dwelling. It sounds like you need the system balancing properly.
Start with all rad valves fully open - both ends. You will need grips/spanner for the lockshield end. Turn on ch to constant. Give 30/40 min to get nice and hot. Go to hottest rad and close lockshieled to only a third open. Then go to next rad and turn down almost as much. You get the picture. You're trying to balance circuit so the last rads get same heat as the first rads - and this is done by this method. Leave to heat through until equal heat is achieved. It takes time.
That's chargeable professional knowledge you know [/list]
Setting 2 is usually a sufficient setting for the pump in an average-sized domestic dwelling. It sounds like you need the system balancing properly.
Start with all rad valves fully open - both ends. You will need grips/spanner for the lockshield end. Turn on ch to constant. Give 30/40 min to get nice and hot. Go to hottest rad and close lockshieled to only a third open. Then go to next rad and turn down almost as much. You get the picture. You're trying to balance circuit so the last rads get same heat as the first rads - and this is done by this method. Leave to heat through until equal heat is achieved. It takes time.
That's chargeable professional knowledge you know
[/list]Thanks for the reply. I have read quite a lot on this forum about balancing the system, so I shall give it a try first. I have noticed that the lockshield on the bathroom rad does not seem to be adjustable, it looks a bit different to the others. As if it has another bit added to the top.
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Just make sure it's fully open first. What is the difference? Is it openable? If you can't open it manually try removing the head/cap - this could be the system bypass. Make sure you return this to its original position.
The whole process can take about two hours. Best of luck
The whole process can take about two hours. Best of luck
Chess: The valve seems to have some sort of extended stem on it. I have been told before that the bathroom radiator was used as the bypass or heat sink for the system and wondered if this was some sort of locking mechanism.
Nige F: The 3 way was not an identical replacement and iniially I did put it the wrong way. For me to install it right the A and B parts of the valve are now reversrd from the original. (I think the original was a Danfoss and the new one is a Tower)
Nige F: The 3 way was not an identical replacement and iniially I did put it the wrong way. For me to install it right the A and B parts of the valve are now reversrd from the original. (I think the original was a Danfoss and the new one is a Tower)
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