Combi-condensing boiler & TRV's...

j4n25

... hope this makes sense.

We have a combi-condensing boiler, all rads have TRV's apart from bathroom rad. No room stat.

What is best thing to do, have the boiler on high and TRVs on low, or boiler on low and TRVs on high, to get the best out of the boiler, and also cheapest to run.

Do I make sense?? Hope so,.......

latecomer

The TRVs are independent of the boiler setting.

If they are set to 1 then when the room temp reaches the correct temp they shut off.
Having the boiler set to low will mean that the rooms take longer to heat up. It will probably also affect your hot water temp too. So try setting the boiler on low and if you find the water temp too low or your rooms take too long to heat up then increase the boiler setting.

Does that help?

edit. Didn't really answer the question did I? As for the most economical way of using it, I have no idea. Does the manual not give any indication of the best way to use it?

want2bmortgage3

hi j4n25 I have exactly the same setup and was thinking of asking the same question! My boiler has seperate temperature settings for water and heating. Currently my hot water is set at 45 and heating at 82 (the highest it will go). 45 for water is hot enough for a bath / shower with taps on hot only, but not too hot to scald. I decided it would be best to put the heating on the highest temp as it means the boiler will be on a minimum amount of time. This made more sense to me than setting it lower and having it take longer to heat the rooms. As for the TRVs I would set them all quite low (mine have a frost setting as a minimum) and see how you find it. I havent experimented enough yet to advise on what number to set the valves. If yours are bulldog valves too then I can tell you what temperature each number means as I still have the little leaflet that came with them.. hope that helps!

Canucklehead

Good evening: Consult your boiler's user manual and the Energy SavingTrust for information on heating controls (and get yourself a programmable room stat;))

HTH

Canucklehead

Devon_Hippo

want2bmortgage3 wrote: »

h. Currently my hot water is set at 45 and heating at 82 (the highest it will go). 45 for water is hot enough for a bath / shower with taps on hot only, but not too hot to scald. I decided it would be best to put the heating on the highest temp as it means the boiler will be on a minimum amount of time.

Hi - this is ok on theory and you mention abiut scalding for hot water. Do not forget you can burn yourself on a rad !!!

TRVs on a rad do not control the temperature of a radiator, they control the temperature of a room. if the Central Heating boiler is set at 82, then the rads - while they are on - are also near enough at 80C and WILL Burn. The Rads will turn off quicker sure, as the room may heat up faster, but while they are on, they will be very hot.

This is especially important when you have a towel radiator in a bathroom as there will be naked flesh in a bathroom that could brush against a rad and this is very painful, believe me.

want2bmortgage3

thanks devon did not think of that.. any ideas on a suitable temperature for the central heating?

canuckelhead.. with a room stat wont you get uneven temperatures between rooms, depending on sunlight etc? i'm sure i was told TRVs are better as you can get each room just right

j4n25

hi j4n25 I have exactly the same setup and was thinking of asking the same question! My boiler has seperate temperature settings for water and heating. Currently my hot water is set at 45 and heating at 82 (the highest it will go). 45 for water is hot enough for a bath / shower with taps on hot only, but not too hot to scald. I decided it would be best to put the heating on the highest temp as it means the boiler will be on a minimum amount of time. This made more sense to me than setting it lower and having it take longer to heat the rooms. As for the TRVs I would set them all quite low (mine have a frost setting as a minimum) and see how you find it. I havent experimented enough yet to advise on what number to set the valves. If yours are bulldog valves too then I can tell you what temperature each number means as I still have the little leaflet that came with them.. hope that helps!

hiya, mine has seperate settings for water and heating, water is set at 7, dont know what temp that is. I will put my boiler on high n trvs on 3/4, they go upto 5. DOnt know if they r bull dog valves, they have 0, frost, 1,2,3,4,5 on them. Ta j

want2bmortgage3

if they are bulldog that will be written on them somewhere... here are the temp's i'm sure they will be similar whoever made them..

0 - shut off
* - 7c
1- 11-13c
2- 15-17c
3- 19-21c
4- 23-25c
5- 27-29c

this kind of makes me think well you might as well have the heating on for a reasonable amount of time, and just set the rooms accordingly. coz once the rooms at temp then its going to shut off and not cost any more than necessary.

j4n25

want2bmortgage3 wrote: »

if they are bulldog that will be written on them somewhere... here are the temp's i'm sure they will be similar whoever made them..

0 - shut off
* - 7c
1- 11-13c
2- 15-17c
3- 19-21c
4- 23-25c
5- 27-29c

this kind of makes me think well you might as well have the heating on for a reasonable amount of time, and just set the rooms accordingly. coz once the rooms at temp then its going to shut off and not cost any more than necessary.

still dont know whats best to do, should i put our boiler on 4/5 (think it goes upto 7), and the trvs on 4???? or put boiler on same as above but trvs on lower. argghh so confusing, just want to get the best out of the boiler without it costing a fortune in gs. I think last year we had it on a timer, had it on 6, then set the trvs in our lounge, kitchen, as nr enough 1 room at 4, then rest on low.

Thanks J

latecomer

You are missing the main point. The TRV setting is not related in any way to the boiler temperature. The TRV will shut off when then room temperature reaches the set value. i.e. using the settings from above - TRV set to 3 will shut off when the room reaches 19-21 degrees c.

The boiler temp will dictate how hot the water is, hence the temperature of the radiator surface but not the room temperature.

why not try running it for a week with the boiler set on max, then a week with the boiler set on 4/5 and check the amount of gas you use? Provided you do approximately the same amount of cooking (if you use gas) then it should give an indication of whats the most economical setting.

want2bmortgage3

in theory i would guess setting the boiler at max would be more efficient , which is what i've done , but then the issue of scalding that was brought up made me think of dropping the boiler temp slightly.. but not sure what is the highest temp without the rads being too hot