Valiant anti cycling function

[Diana1990]

Have you looked at the boiler return temperature, d.41?.

Hi guys. New rads fitted. There was barely any debris or sludge, just slight in that one rad in my room, they drained it all out and water was barely discoloured. Flat sooo cosy. So after they left I kept heating on and checked the temps. 40 - 61c. 41 - 56c

 

[Johntheo5]

What do those flow/return temps mean? is the boiler running continuously?

 

[Diana1990]

What do those flow/return temps mean? is the boiler running continuously?

It had been on about 55mins at least. Potentially over an hr

 

[Johntheo5]

Your rads will be emitting 53.7% of max at flow/return temps of 61C/40C, the min output of your boiler is ~ 6.0kw if its running continuously close to its minimum then, by calculation, the T50 (100% output) rating of the 7 rads is 11.2kw or 1600W/rad, seems very high for single panel rads.
I'm surprised the boiler isn't cycling. (if its min output 6kw.)

 

[Diana1990]

Shall it bring the kwh down? It's at 18kwh atm. The rads we had put in were single panel plus. Do not your standard singled panel

Do you suspect a issue?

The service was also done and everything looks tip top shape

 

[Johntheo5]

No. I certainly dont, did the installer not give you theeir outputs if they supplied them, it wouldu be nice to know, also the 20C dT is interesting, wonder is that set in the d parameters or just by chance due to pump speed or whatever.

 

[Diana1990]

No. I certainly dont, did the installer not give you theeir outputs if they supplied them, it wouldu be nice to know, also the 20C dT is interesting, wonder is that set in the d parameters or just by chance due to pump speed or whatever.

20c difference? It was only 5c.

 

[Johntheo5]

61C - 40C = 21C ??
If not what ARE the flow and return temps now that the boiler is running continuously

 

[Diana1990]

61C - 40C = 21C ??
If not what ARE the flow and return temps now that the boiler is running continuously

Sorry.... So basically D40 was 61c. D41 was 56c. Maybe I didn't write or correctly

 

[Diana1990]

Here is snapshot I took earlier

 

[Johntheo5]

OK. that means you are getting ~ 70% RAD output.

 

[Diana1990]

OK. that means you are getting ~ 70% RAD output.

No idea if that's good.....

 

[Johntheo5]

Its good if you decide to run on a reduced number of rads for whatever reason, room(s) heating not required etc, and because of a high flowrate means easier boiler refiring after cycling, you can also just reduce the targettemp to give reduced output if required, for example if you reduced the targettemp (= flow temp, d.40) to say 45C then the rad output is reduced to 38% with a very good boiler efficiency at a return temp of 42/43C. You can just use the targettemp to achieve almost any level of comfort heating you require.

 

[Diana1990]

All my rads would always be on, I keep them set on max or lowest 4

 

[Johntheo5]

You will have a very warm house if the TRVs are set to 4, well over 25C IMO, I have mine se to between 2.0 and 3.0 to give ~ 16C to 22C.