Most Efficient Settings?

MintyCyrmu

Hello all, I live in a rented accommodation that is fitted with a combi powered central heating system.

There are 9 radiators, 7 of which have thermostatic valves.

My question is, in the absence of a full control thermostat, what is the most efficient set up?

1 - To run the heating temperature on the boiler up high, and keep the thermostatic radiator valves down

2 - To open the thermostatic radiator valve full open and turn the heating temperature down on the combi

...or, any other way?

Thanks!

lstar337

The combi will likely have a temperature at which it uses best use of the gas (where it is most efficient), on mine it is marked with an 'e' on the dial but you may have to consult your handbook.

[STRIKE]Generally, if condensing then the boiler likes to be up high, which is how I would have it anyway to get heat into rooms quickly.[/STRIKE]

Then use your radiator stats to sort your room temperatures out.

Are you sure there is no central thermostat?

Where are the rads with no stat valves?

penrhyn

Are you sure there is no programmer, it might be a wireless device and hidden away somewhere.?

sk240

A condensing combi boiler will run more efficient the lower you have it set (it uses the exhaust from the boiler to pre heat the water)
I run mine at 50'C, but that may not be high enough to keep your house warm, just set it as low as you can and still maintain the temperature and achieve a reasonable room warm up time.

Set the rooms upstairs at about no 2 on the TRV (usually 18-19'C) and downstairs at about no3 (usually 20-21'C)

You should really have a room thermostat fitted somewhere though (usually bottom of the stairs) you can get wireless ones installed for not a massive amount of money, otherwise your boiler will be on 24/7 whether there's any heating demand or not.

Wherever the room thermostat is situated, the TRV should be set at maximum.

Cardew

lstar337 wrote: »

Generally, if condensing then the boiler likes to be up high, which is how I would have it anyway to get heat into rooms quickly.

sk240 A condensing combi boiler will run more efficient the lower you have it set (it uses the exhaust from the boiler to pre heat the water)

See:

https://forums.moneysavingexpert.com/discussion/comment/66738827#Comment_66738827

lstar337

sk240 wrote: »

A condensing combi boiler will run more efficient the lower you have it set (it uses the exhaust from the boiler to pre heat the water)

Sorry sk240, I may be barking up the wrong tree here, but isn't that flue heat recovery that you are describing?

EDIT: I guess you mean through the creation of condensation rather than through direct heat recovery. I'll stop digging my hole now.

lstar337

Check over here: https://forums.moneysavingexpert.com/discussion/comment/66739279#Comment_66739279

For my response to Cardew's excellent question.

sk240

the boiler runs most efficient the cooler that it is run, it uses the waste heat going out the exhaust to pre heat the incoming water.
The more of a differential there is between the return water and the exhaust temp, the more efficient it is.
vaillant for example quote there max efficiency at 50'C water flow, and 30'c return.
http://www.which.co.uk/home-and-garden/heating-water-and-electricity/reviews/boilers/page/features-explained/