VERY HOT RADIATORS

[PaulBulos]

I have a Potterton Kingfisher CF60 boiler. A few recent problems with the heating and hot water system and so we recently had the cylinder thermostat changed, the pump, the timer and the change over (HW/CH) changed also. There are no room theromstats, but the radiators all have thermostats. Anyway, a few visits from Brit Gas and all done, and system working again, but blimey are the radiators scoldingly hot!!!

I opened the boiler to see that the control knob was on Max, which I assume means the boiler just kept on firing and heating and heating - would that be the cause of the boiling radiators. It has a min, levels 1-5 and max, I have now turned this down to between 2 and 3 in the hope that it will heat the water, fill the radiators, and switch off the firing up and maintain a regular temp - sound about right??? Oh all radiator thermostats on low!

Love to have some advice. We have small children (11 month old touches everything) so I need to know how to regulate my radiators so not so hot.

 

[kevplumb]

would that be the cause of the boiling radiators. It has a min, levels 1-5 and max, I have now turned this down to between 2 and 3 in the hope that it will heat the water, fill the radiators, and switch off the firing up and maintain a regular temp - sound about right??? Oh all radiator thermostats on low!

yes

 

[jackthom]

Yes the boiler control is the correct one to adjust.

Note that turning down the thermostatic valves on the radiators won't really help because they are designed to shut down the flow of water when the room has reached the required temperature.

They don't really control water temperature as such.

 

[PaulBulos]

Thanks for that, and so quickly too!

So being that the control was set to "Max", would that fully explain the radiators getting so hot?

So, what should happen now then is that the boiler comes on (control in boiler set between 2 and 3 only) - the boiler fires up, heats the water which is pumped (now very efficiently) through the system, fill radiaotrs with hot water - and then once the water has heated to a certain temp the boiler doesn't fire, hence not heating further and the temp of the radiators is settled at a more moderate heat?

I'd be really grateful for a bit more from you - thanks!

 

[D_Hailsham]

There are no room thermostats,

Fit one!!! At the moment the only control you have over the boiler is the boiler's own thermostat. That's not sufficient - as you have found.

 

[kevplumb]

imagine your boiling a pan of water

how do you get it down to a simmer

reduce the heat

well in effect turning the boiler stat down has the same effect

 

[PaulBulos]

But the system has been fine and the radiator temps previously (i.e before recent work when I guess someone must have turned control know up to MAX) - so is it worth the work of fitting a room thermostat???

 

[PaulBulos]

Thanks Kev, that is kind of what I thought really but it sounded too simple - and is that knob in the boiler that I have turned the one to reduce the heating effect?

I am also assuming that with a new pump and valve the system is more efficient and so as soon as water starts heating it heats radiators quick.

What would be best to set the level of the control knob at - 2-3 do you think, to avoid boiling radiators?

Oh when the heat was seriously high, the pipes and pump where making quite a sound too - presumably the water was just too hot in the system?

 

[kevplumb]

just set it to what suits you

there is no hard and fast rule

 

[PaulBulos]

Thanks again Kev, I just want the radiators to fill but not be absolutely scolding, as long as this stops that, or at least of they fill hot and cool a bit, then I am happy - do you think this will work?

if it isn;t this, what else might it be?

 

[kevplumb]

yes it will be ok

if your not sure turn it down to 1 and see what difference it makes

stop flapping

 

[PaulBulos]

Thanks Kev - I am not flapping, just don't want my children to be burned, and my wife doesn;t understand anything to do with it!

It all sounds sensible, and logical, but boy was the bathroom radiator hot and there some noises through the pipes - why oh why did the gas engineer leave it on MAX!!!

 

[D_Hailsham]

At the moment the boiler will keep running until the boiler's thermostat turns the boiler off. This could be long after the rooms have reached temperature. There is also the problem that you have to change the boiler temperature to match the requirement - high when it is cold outside, low when it is warmer.

Fitting a room thermostat solves both of these problems and will save you fuel.

 

[PaulBulos]

Is fitting a room thermostat a difficult job?

 

[D_Hailsham]

Is fitting a room thermostat a difficult job?

Not really. Depends on what components (timers, motorized valves, thermostats etc) you already have. Can you list what you they are (makes and model nos)?

You mentioned a cylinder thermostat and a CH/HW changeover switch. This suggests that you have a pumped heating/gravity HW system. Is this correct? You can tell by the number of water pipes connected to the boiler. A pumped heating/gravity HW will have four pipes connected; a fully pumped system will have only two pipes.