Hi all,
I will start with a bit of background about the system --
* 12 radiators of varying size
* 10mm microbore copper + some 10mm plastic
* TRVs on all but one radiator (the one being located in the coldest room)
* Wireless stat
So, here's the problem --
When we het to this time of year - and the TRVs shut down all the rads in the house apart from the open one... The boiler struggles to provide heat for long enough to heat the water in the open part of the system.
To put this another way - the boiler ignites for about 10s then goes off for a minute or so...
The net effect is - the single open rad only gets a very small burst of hot water followed by loads of tepid water.
I have tried closing this rad and opening one of the others and the same thing happens - so, I do not believe this is simply an issue with the normally open rad.
In addition, I have flushed this entire part of the system and there is certainly no blockage or the like.
Also, the CH outlet pipe remains very hot to the touch for quite some time after the burner has shut off which suggests to me the water is not being circulated fast enough?
The pump is on the fastest setting (3) and seems fine when several rads are open. In fact, the whole house is adequately heated during the winter months (including the cold room).
When several rads are open the CH outlet pipe does cool down after the burner shuts off - so the water is definately circulating through the boiler faster when many rads are open.
So, there are several things going through my mind -
1) The pump is struggling when under higher restrictive load. More torque is required when a single rad is open as opposed to when all rads are open.
Do pumps suffer tis kind of problem?
2) The burner is not regulating correctly based on flow.
That is, the burner is burning too ferociously for the reduced flow resulting in the burner cutting out.
Although, I would still expect the CH outlet pipe to cool down shortly afterwards (which it doesn't) - which brings me back to [1]
3) The boiler is simply overpowered for a single rad - although the fitting instructions suggest this should not be the case.
And help or advice would be greatly appreciated...
Thanks in advance...
gazbiggs[/list]
I will start with a bit of background about the system --
* 12 radiators of varying size
* 10mm microbore copper + some 10mm plastic
* TRVs on all but one radiator (the one being located in the coldest room)
* Wireless stat
So, here's the problem --
When we het to this time of year - and the TRVs shut down all the rads in the house apart from the open one... The boiler struggles to provide heat for long enough to heat the water in the open part of the system.
To put this another way - the boiler ignites for about 10s then goes off for a minute or so...
The net effect is - the single open rad only gets a very small burst of hot water followed by loads of tepid water.
I have tried closing this rad and opening one of the others and the same thing happens - so, I do not believe this is simply an issue with the normally open rad.
In addition, I have flushed this entire part of the system and there is certainly no blockage or the like.
Also, the CH outlet pipe remains very hot to the touch for quite some time after the burner has shut off which suggests to me the water is not being circulated fast enough?
The pump is on the fastest setting (3) and seems fine when several rads are open. In fact, the whole house is adequately heated during the winter months (including the cold room).
When several rads are open the CH outlet pipe does cool down after the burner shuts off - so the water is definately circulating through the boiler faster when many rads are open.
So, there are several things going through my mind -
1) The pump is struggling when under higher restrictive load. More torque is required when a single rad is open as opposed to when all rads are open.
Do pumps suffer tis kind of problem?
2) The burner is not regulating correctly based on flow.
That is, the burner is burning too ferociously for the reduced flow resulting in the burner cutting out.
Although, I would still expect the CH outlet pipe to cool down shortly afterwards (which it doesn't) - which brings me back to [1]
3) The boiler is simply overpowered for a single rad - although the fitting instructions suggest this should not be the case.
And help or advice would be greatly appreciated...
Thanks in advance...
gazbiggs[/list]
