Optimumtemperature settings for Gas boiler

skycatcher

Hi,

I had a WB Greenstar 30i installed last spring which the installer set the CH temp at 74 and the Hot water at 55. This is a 3 bed semi. I found there is an adjustment on the boiler settings that allows it to set its ideal temps. Using this it set the CH to 61 and HW to 50. 

Is the an actual recommended temp for optimum efficency? I know there is an ideal temp drop between flow and return but I have no way of measuring this.

Thanks.

QrizB

The colder the better, subject to your house & water being warm enough for you. For example I'm running my regular boiler (so both CH and HW on the same control) at 50 but I have to turn it up to 55 or 60 if the weather's freezing.

Give it a go and see how you get on.

FreeBear

Bear in mind, as you reduce the temperature of the CH system, the heat output of the radiators will also drop. Unless the radiators have been designed & correctly specified for a lower temperature, the house may not be as warm as you'd expect/like.

matelodave

Keep turning it down until you are cold then increase it by a degree or so unto you get the right balance between being warm enough and the reheat time of the rooms.

As said above, turning the temp down will reduce the output of the radiators which will increase the time it will take to get the house warm however the lower you can get it the more economical it will be.

BUFF

What controls are you using with it? Some will automatically vary & optimise the CH flow temps for you according to load and/or weather doing a better job than you could manually.

skycatcher

BUFF said:

What controls are you using with it? Some will automatically vary & optimise the CH flow temps for you according to load and/or weather doing a better job than you could manually.

It came with the standard room thermostat EPC is its name and TVRs

BUFF

I don't recognise that room stat name - can you post a photo or give a model no.?

skycatcher

Apologies it's actually an EPH controls ...no model no. on it.

BUFF

can you post a photo? https://www.ephcontrols.com

skycatcher

https://www.ephcontrols.com/section/cp4/

This is the one...i tried a photo but an error kept coming up.

lohr500

It is important that you try to get a 20 deg C differential between the flow and return temperatures out of and back into the boiler, with the return no higher than around 50 deg C. A lower return temperature whist maintaining the differential is even better. 
This allows the boiler to condense effectively which improves efficiency and saves cost.
You can buy low cost clip on thermometers like these to measure the flow and return temperatures :

 https://uk.rs-online.com/web/p/dial-thermometers/4315621?cm_mmc=UK-PLA-DS3A-_-google-_-PLA_UK_EN_Test_&_Measurement_Whoop-_-Dial+Thermometers_Whoop+(2)-_-4315621&matchtype=&pla-514615894072&gclid=CjwKCAiAz--OBhBIEiwAG1rIOiY0_eHAKsQbGw3SEjiqGgI78kA4sabaaCtdnBnzry8Srz0H86xBcRoCbdsQAvD_BwE&gclsrc=aw.ds

To get a 20 deg differential on our system (60 deg flow, 40 deg return) I had to play around with the circulation pump speed and also balance the radiators. I also had to adjust the boiler thermostat setting to tweak the max output to 60 deg C.