Posted by: @jeegnesh

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Overnight 42c target.  the first curve is my hot water tank run which shows the system is capable of high flow temp.  

 

OK. Please confirm heat curve and max flow temp settings last night.  Are you 100% certain noise reduction mode is off.  Something is capping flow temp in space heating mode, the question is what!

If you have 2 zones on the controller check settings for both.  Not sure how 2 zones are supposed to work TBH!

Is it possible heat pump is working at max output so whats capping the FT is just heat loss?  Power consumption suggests thats possible.  Can you get data on energy delivered, better still compressor modulation.  You can see the latter in live monitor on the HPAI (and the bar to the left of the display gives a permanent visual indication).

There are still things that don't stack up in this chart (reproduced to avoid the need for page hopping):

Why does the power drop to zero during the peak of the DHW cycle? 

Why do the next two 'anomalies' go in opposite directions, while the flow temp drops in both cases?

Are the other power drops just simple cycling, or more likely defrost cycles, given the OAT?

Another thought: can you plot the set flow temp against the actual flow temp? That would distinguish between a controller problem (not setting the right flow temp) and a delivery problem (right set temp, but heat pump fails to deliver it). 

Why does the power drop to zero during the peak of the DHW cycle? 

No idea, maybe a lag in home assistant pulling data

Why do the next two 'anomalies' go in opposite directions, while the flow temp drops in both cases?

Your guess is as good as mine, Could that be a defrost?

Are the other power drops just simple cycling, or more likely defrost cycles, given the OAT?

I think cycling maybe the over 4k ones are defrost (guess)

Another thought: can you plot the set flow temp against the actual flow temp? That would distinguish between a controller problem (not setting the right flow temp) and a delivery problem (right set temp, but heat pump fails to deliver it). 

I wanted this too, but HA plugin does not have the target, I am given those numbers by looking at the wired controller, I will check again though.

Posted by: @jeegnesh

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I wanted this too, but HA plugin does not have the target, I am given those numbers by looking at the wired controller, I will check again though.

I think that is an important step, to narrow down where the problem lies, even if you need to do it manually.

PS didn't mean to rattle off a lot of quick fire questions in my last post, they just came out that way. 

OK. Please confirm heat curve and max flow temp settings last night.  Are you 100% certain noise reduction mode is off.  Something is capping flow temp in space heating mode, the question is what!

Hc = 0.5, MAX FLOW = 50c the NR schedule is blank

If you have 2 zones on the controller check settings for both.  Not sure how 2 zones are supposed to work TBH!

I made sure both were identical settings, I had even tried with turning one off.  So the way it works is that if the downstairs hits temp then are shutdown at the manifold so giving the rads all the flow.  (That was the thoery I was told)

Is it possible heat pump is working at max output so whats capping the FT is just heat loss?  Power consumption suggests thats possible.  Can you get data on energy delivered, better still compressor modulation.  You can see the latter in live monitor on the HPAI (and the bar to the left of the display gives a permanent visual indication).

So my next run is about to begin so I can get the modulation then I got a feeling it was 80% but will check and tell you. I can give you the yeild figures for that night run from vaillant app:

Posted by: @cathoderay

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I think that is an important step, to narrow down where the problem lies, even if you need to do it manually.

PS didn't mean to rattle off a lot of quick fire questions in my last post, they just came out that way. 

That is ok, helps me look at more things.  So probed AI and it claims this entity should exist, but i've looked carefully and it is not there.  Manual would mean visting my plant room very often, my missus is already wondering what the hell is he doing, why does he keep going there and scratching his head.

Just to add, I've fired an eMail off to HG my install supplier as I feel there is enough info to get them to start scratching there heads.

Posted by: @jeegnesh

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Manual would mean visting my plant room very often

I think just a few readings would be useful. Try to pick a time when the OAT is low, and do the same again when it is higher, and you have two points that in effect define your WCC. You can then compare the set flow temp to the actual flow temp, which practice varies (the saw tooth pattern), so you may need to take an average. Even simpler, just take one reading of the set flow temp at a known point in time, and then look at the chart of actual flow temp at that point in time, and see how the two compare.

I do record the set flow temp (LWT) in my data. As you can see from the chart below, on the left, with the heat pump not cycling, the set and actual LWT are very close. When it defrosts (middle of the chart), the peaks of the actual LWT reach the set LWT, but the average actual LWT will be lower than the set LWT, while on the right, after the DHW heating spike, it is doing what it normally does, the actual LWT cycles above and below the set LWT, with the average close to the set LWT.  

Posted by: @jeegnesh

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Hc = 0.5, MAX FLOW = 50c the NR schedule is blank

Noted NR is definitely off.

According to the Vaillant manual weather comp curve 0.5 is about 35C at 0C OAT  Suggest you bump this up to say 0.8 which is 42C at 0C, and the max FT up to 55, just to ensure that is having no effect.

So 66kWh generated which would be 10kW over 6.6 hrs but Im guessing the period may be more than that.  According to the spec sheet the 10kW model is good for nearly 12kW at 0C/35C.  Now its said these dont include defrosts, but all the same you should be getting 10 easily.  However it could (just) be 'close'.

My curve figures seem way different to that but I've changed it to 0.8 as you said, may as well try everything.  Here some stats from the controller directly:-

Does that image show a target flow temp of 49°, and a current flow temp of 33°C (the images are rather blurred). If so, and it is not in the deep trough of a defrost, then I think you have narrowed down the problem to something on the delivery side of things, ie tweaking the curve settings isn't going to fix it.  

Finally caught it on the drop, although its mighty cold out there, it says de-icing mode active, adding this afternoon/evening run thus far.