Radiator setting

[sherrardk]

We've got a new combi boiler and there is a setting on it for how hot you want the radiators. All except one of our radiators has individual controls on them. Does the extra control on the boiler have any significance in our situation? I currently have it set to the maximum for the radiators (the boiler setting that is). Thanks

[boxtops]

We keep our combi boiler idling at 50 degrees - the radiator valves are rarely touched, just "on", then the temperature is controlled from the thermostat on the wall.

[AlBags]

Keep it on max always. The system will run more efficiently.
The extra rad is just to ensure water is passing around the system permanently when pump running. They 'could' have fitted a Honeywell bypass valve tho!

[The Builder]

Sherrard .......... plumbers tend to set the boiler (CH) on about three quarters. Same with the HW. It would be economical with these settings. You shouldn't need the boiler going flat out if the system has been designed properly.

There is always one rad without a TRV. It's called a "heat leak" rad. The idea is that, if all the TRVs are off (because the temp is high enough), then the heat leak rad dissipates extra heat to save overheating the boiler. So you might find this one hot when the others aren't.

[The Builder]

Al ........... max, really?

[AlBags]

A good system with good quality TRV's does not need a thermostat .. although for variable temperature control with TRV's, you can use a programmable stat. so long as there is a good position for it.

[sherrardk]

Thanks Boxtops. I am having trouble getting the downstairs rooms just right, will just have to keep tinkering with it.

[sherrardk]

Sorry, you weren't all there when I started typing (and then got caught up watching the last ten minutes of Spooks). I find the living room radiator is not getting warm enough (even when set to number 5). Will have to keep altering them till I am happy with it.

[AlBags]

Yes mate.

Also, boilers that run in condensing mode need to run nice and hot and sense a good temperature drop on the return. Otherwise they will not get into condensing mode.

Hot system water adjusts heat requirement in a room more quickly too .. which 'should' help with boiler start stop every few minutes.

[AlBags]

If the rad is not warm enough .. yet others are .. it will be ..

1. System balance. Throttle back rads on lockshields nearest pump first. This will push flow to furthest rads.
2. Lockshield screwed down too much.

[sherrardk]

Sorry Al, I have no sodding idea what any of that means (it is nice and hot know that the boiler radiator setting has been altered to max). I am not going to mess with it too much as himself is fitting a wood burning stove soon (or so he says) so that will alter things again.

[The Builder]

Right ........... I've got a condensing Vaillant .......... I'm off to change the settings . You learn something every day in this business.

[AlBags]

lol mate : )

I just hope the rads are sized right! Otherwise it may 'never' get into condensing mode.

[AlBags]

You can read about it here and make your mind up ..
Some insist condensing works 55 deg out and in or below .. but there are other issues to deal with .. which may ruin your efficiency .. if connected to a HW cylinder. You may decide to run lower and more permanently at a reduced temperature .. although I won't!
http://www.condensingboiler.org.uk/

[AlBags]

Another view ..
http://www.gasman.fsb...ondensing_boilers.htm

If you have a correctly sized system (maybe even with a slightly under-sized boiler) and get the balance right .. the return temp can be got down to 55 which is probably the best you can do. The main thing is getting the drop so you can use higher outlet temp. That's how I balance mine up .. and pump is on lowest setting too.

[annie0000]

Sher, what I think AL is saying is that if you lower/shut down the other radiators until you get the living room one hot, then adjust the others back on until it balances out. :o)