is it possible? with only a control valve and LSV? if so how? cheers
making a single Rad warm up slower than the rest
- Thread starter bhm1712
- Start date
Possibly. Depends on design of system. You should be able to balance it down (Check FAQs for balancing) but it may end up noisy as the water rushes through the LS valve.
The more the valve is closed, the less water goes through the valve. Most of the water will rush past the valve along the 15mm or 22mm pipe.
I guess the OP is having problems with the wall thermostat cutting off before the TRVs in other rooms can do their job. The first thing to do then is to balance the system. If that does not solve the problem, because the rad near the thermostat is oversized, then reducing the flow through that rad is one solution.
As you close the LS valve down, the flow through the radiator is reduced, so the temperature at the return drops, the average water temperature reduces and the radiator emits less heat.
hi again D_Halisham.
if you can remember from a couple of weeks ago, i had trouble with water flow noise in my upstairs rads. after hours of balancing i got the system fully balanced again, but the noise remained in the upstairs. i have since traced all of the heating pipes and found the following:
the 22mm flow pipe goes from my boiler, up into bed1 and anti clockwise round the upstairs to bed3 where it turns back to the boiler as return. along the way it feeds bed1, bathroom, bed2, bed 3. in between bed1 and bathroom there is the first branch off to downstairs in 8mm microbore to the living room rad. the kitchen and hallway rads branch off just before the supply to bed 3 rad. therefore, due to the crap way of piping the downstairs up, when the LSV on the Bed1 rad is open just right to stop the flow noise, it starves the branch to the downstairs living room rad, and likewise for the 2 other downstairs rads from Bed3.
i have concluded i have to live with either cold downstairs rads or noise upstairs!
if you can remember from a couple of weeks ago, i had trouble with water flow noise in my upstairs rads. after hours of balancing i got the system fully balanced again, but the noise remained in the upstairs. i have since traced all of the heating pipes and found the following:
the 22mm flow pipe goes from my boiler, up into bed1 and anti clockwise round the upstairs to bed3 where it turns back to the boiler as return. along the way it feeds bed1, bathroom, bed2, bed 3. in between bed1 and bathroom there is the first branch off to downstairs in 8mm microbore to the living room rad. the kitchen and hallway rads branch off just before the supply to bed 3 rad. therefore, due to the crap way of piping the downstairs up, when the LSV on the Bed1 rad is open just right to stop the flow noise, it starves the branch to the downstairs living room rad, and likewise for the 2 other downstairs rads from Bed3.
i have concluded i have to live with either cold downstairs rads or noise upstairs!
like so
In your diagram you show a link between the main flow and return in bedroom 3. This link shouldn't be there - unless it's a bypass valve or something like that. If it's an open connection then there is the cause of your pressure problems.
thats where the flow pipe doubles back on itself and becomes the return pipe....
In a two pipe heating circuit, there should be no connection between flow and return other than through the radiators or a bypass valve. The flow and return shouldn't be joined!
If I remember correctly you have a c-plan system. If it were my house I would add an automatic bypass valve at the junction between flow and return, this would maintain the pressure differential whilst preventing any no-flow situation should the radiators all be closed.
If I remember correctly you have a c-plan system. If it were my house I would add an automatic bypass valve at the junction between flow and return, this would maintain the pressure differential whilst preventing any no-flow situation should the radiators all be closed.
there is no bypass valve on my system, its an old system so i dont know if this makes a difference. what would happen if somebody decided to turn all the radiators off? the pump would be pumping to a dead end and something would blow.... there is definitely not a bypass valve anywhere.
well i say that, but i cannot find one on the pipework anywhere but bear in mind i am looking into the floor voids with a torch and only one floor board up, would it be put under the floor? or normally near the origin of the 2 pipes?
Usually the bypass is near the boiler, pump or motorised valve(s). I think it's very unlikely that there would already be one installed on your system, given its age.
If there is a radiator with two lockshield valves then this can act as the bypass, although it's not modern practice.
Currently, if all the radiators are closed the water will flow through the connection between flow and return in bedroom 3. However this open connection will be 'stealing' pressure from the radiators as it's the path of least resistance, this will make the system near-on impossible to balance correctly.
You could install an auto bypass valve in place of the open connection between flow and return, or you could cap off the open connection and fit a bypass somewhere else - after the pump of course.
If there is a radiator with two lockshield valves then this can act as the bypass, although it's not modern practice.
Currently, if all the radiators are closed the water will flow through the connection between flow and return in bedroom 3. However this open connection will be 'stealing' pressure from the radiators as it's the path of least resistance, this will make the system near-on impossible to balance correctly.
You could install an auto bypass valve in place of the open connection between flow and return, or you could cap off the open connection and fit a bypass somewhere else - after the pump of course.
i will have a look at this open connection again and make sure there is no relief valve on it. none of the rads have 2 lockshields. its a rubbish pipe setup me thinks, done on the cheap when the house was built i would imagine
Quite probably! Judging by your drawing though it should be reasonably easy to sort out.
Could it have been a one-pipe converted to two pipe?
At the risk of confusing the OP! I did find a website which said that the flow and return should be joined - but nobody else agrees.moggett said:
- and I can't find it now, so it's probably been removed or corrected 
Hmm, curious!
I guess the 'bodge it and leg it' fix would be to add a gate valve and balance it along with the rest of the system
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