My Nibe F2040 and SMO40 controller has been stable for a long time, but recently I’ve noticed some odd behaviour on the DHW which I can’t understand. The heatpump is set to manual operating mode so is only doing DWH.
The settings are “normal mode” with on at 40 degrees and off at 50°. I have not changed the settings but the behaviour is new. I have captured some recordings from myuplink. Has anyone seen this behaviour before or can help diagnose what may be happening?
Hi Sam,
Sorry to hear you’re having DHW issues. As you know, there are very few options associated with DHW on the NIBE controllers so there’s not much scope for problems as long as the BT6 sensor is providing an accurate reading of cylinder temperature.
I’m reminded of this other post about DHW cycling on a NIBE unit - which turned out to be low flow rate due to a partially blocked filter; that might be something to check / rule out if you’ve not done that already:
Hi @etchelsa
I don’t have a Nibe but if I understand your Viewer output correctly your DHW tank top temperature is a steady (and very respectable) ~57degC (BT7). Assuming 5-7degC layering in the tank, your tank base could easily be the 50degC of your stated target. If this is the case, is it possible that your controller is simply cycling the water flow just to maintain this target DHW temperature?
In other words, is there really a problem at all?
PS I’ve noticed that on my Samsung, the controller is tending to overshoot DHW target, simply because the high outside temperatures we currently have make it “too easy” to heat the DHW tank at minimum HP output.
