Valliant Boiler ecotech 832- Heating Partial Load

[tommys1985]

Hi all - looking to optimise my boiler heating to see how to make it more efficient.

My setup is:


Combi boiler, someone configured by engineer to provide heating and also warm up my hot water tank.
The kitchen tap is connected to DHW from the boiler to ensure diverter doesn't jam up? This was the recommendation from Valliant.
4 bed house - 11 radiators in total.


Currently it is running on full 24KWH and 60c. I have noticed the following:

1. Return temp is always 4c difference between flow and return.


I have reduced D014 pump speed to 53% and it has not done anything. What else can I do to increase efficient of the boiler?

 

[Harry Bloomfield]

What else can I do to increase efficient of the boiler?

Do what I did, replace your present controls, with a Vaillant control system.

 

[tommys1985]

Do what I did, replace your present controls, with a Vaillant control system.

can I ask what you went for and what changes you have noticed?

 

[Harry Bloomfield]

can I ask what you went for and what changes you have noticed?

The full VRC470F system, including outdoor sensor. It predicts, precisely how much heat it needs to generate, to meet your setting, you just set and forget - it does the rest, tells the boiler how much to modulate. Room temperatures, just remain stable, with no more of the creaking of pipes, as the heating cuts on and off. It also saves a bit of fuel too.

 

[Johntheo5]

Hi all - looking to optimise my boiler heating to see how to make it more efficient.

My setup is:


Combi boiler, someone configured by engineer to provide heating and also warm up my hot water tank.
The kitchen tap is connected to DHW from the boiler to ensure diverter doesn't jam up? This was the recommendation from Valliant.
4 bed house - 11 radiators in total.


Currently it is running on full 24KWH and 60c. I have noticed the following:

1. Return temp is always 4c difference between flow and return.


I have reduced D014 pump speed to 53% and it has not done anything. What else can I do to increase efficient of the boiler?

Hi all - looking to optimise my boiler heating to see how to make it more efficient.

My setup is:


Combi boiler, someone configured by engineer to provide heating and also warm up my hot water tank.
The kitchen tap is connected to DHW from the boiler to ensure diverter doesn't jam up? This was the recommendation from Valliant.
4 bed house - 11 radiators in total.


Currently it is running on full 24KWH and 60c. I have noticed the following:

1. Return temp is always 4c difference between flow and return.


I have reduced D014 pump speed to 53% and it has not done anything. What else can I do to increase efficient of the boiler?
[/QUOTE]

Its very surprising that the dT is only 4C even if all the rad lockshield valves are full open, these boilers have a adjustable bypass screw, normally in mid position and even with a pump speed of 53% might still be bypassing, can you measure the boiler return before it enters the boiler?, I have seen numerous posts where someone has balanced all the rads to give say 15C dT (return measured before the boiler) only to find that the by pass was reduing this to 6 or 7C but yours is exceptionally low IMO, maybe check out this screw, if in its default position then ~ 7 turns clockwise should put in its minimum by pass position but Vaillant then recommend that you increase the pump speed to 100%.
There is also a "d" parameter where you can change to return temperature control but I rarely see anyone using it, might be worth a try?, pump would probably need to be in Auto then.

When you requested 53% pump speed did the speed actually fall to 53%.

 

[tommys1985]

Hi all - looking to optimise my boiler heating to see how to make it more efficient.

My setup is:


Combi boiler, someone configured by engineer to provide heating and also warm up my hot water tank.
The kitchen tap is connected to DHW from the boiler to ensure diverter doesn't jam up? This was the recommendation from Valliant.
4 bed house - 11 radiators in total.


Currently it is running on full 24KWH and 60c. I have noticed the following:

1. Return temp is always 4c difference between flow and return.


I have reduced D014 pump speed to 53% and it has not done anything. What else can I do to increase efficient of the boiler?

Its very surprising that the dT is only 4C even if all the rad lockshield valves are full open, these boilers have a adjustable bypass screw, normally in mid position and even with a pump speed of 53% might still be bypassing, can you measure the boiler return before it enters the boiler?, I have seen numerous posts where someone has balanced all the rads to give say 15C dT (return measured before the boiler) only to find that the by pass was reduing this to 6 or 7C but yours is exceptionally low IMO, maybe check out this screw, if in its default position then ~ 7 turns clockwise should put in its minimum by pass position but Vaillant then recommend that you increase the pump speed to 100%.
There is also a "d" parameter where you can change to return temperature control but I rarely see anyone using it, might be worth a try?, pump would probably need to be in Auto then.

When you requested 53% pump speed did the speed actually fall to 53%.
[/QUOTE]


I don't want to mess with the bypass valve as it means opening the boiler...anything else I can try? the pump does show 53% but if i leave on auto then I have seen 15% also?

 

[Johntheo5]

Can't see it circulating practically anything, at 15% speed. Pump head is proportional to speed squared, this pump will have a head of between 6M and 7M at full speed, say 6.5M, so head at 15% speed will be 0.15 squared X 6.5, 0.15M, it will circulate nothing at that speed, also flow is directly proportional to speed, so IF the speed fell to 15% then the flow/return dT, for the same boiler output should rise to 4C/0.15, 26.7C, theoretically possibly.

The 53% makes some sense, head will be, 0.53squared X 6.5, 1.83, dT shold be 4C/0.53. 7.55C.

You said" Currently it is running on full 24KWH and 60c. I have noticed the following:
1. Return temp is always 4c difference between flow and return."

Do you mean that d.00, the output setting is set to 24kw?

What you could do, which will give some useful info IMO is, With the 11 rads running and up to temperature, gradually reduce d.00 (it can be reduced in 1kw steps) until the flowtemp of 60C just begins to fall off, note the kw setting which will then be the actual boiler output and note flow/return temps, d.40/d.41, can then do a few calcs which might show up something, return d.00 to its original setting when data noted.