Vaillant Return Temperature Control

Joined
15 May 2022
Messages
3,089
Reaction score
764
Location
Cork
Country
Ireland
The majority of Vaillant boilers are configured to run with flow temperature target temperature control, however, on most models, return target temperature control can also be selected which may give greater condensing and boiler efficiency.
If anyone reading this is using this control, they might care to share their experiencies or anyone who is reasonably confident in changing parameters might try this return temperature control for a at least a few hours or so.
Might be best to try this on systems without TRVs or weather compensation.

If flow/return target temperature control is available check for d.17 (there may be a 0 prefix in front of all these d parameters).
d.17 default setting is 0, flow temperature control, return temperature control, is 1.
Before changing, note the following
d.0, part load, ( I think this should be in Auto for return temperature control)
d.5, Flow (or return) temperature target value.
d.40, flow temperature.
d.41, return temperature

Change d.17 parameter from 0 to 1.
Set d.5 initially, to say 5C lower than the current d.41 return temperature.
Monitor d.5, d40 & d.41 regularly for a hour or so.
When test complete return d.17 to 0 and d.5 to its original target flow temperature.

Edit: d.5 (indication only) is set via the normal target value method in either flow or return target temperature mode.
 
Last edited:
Sponsored Links

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top