Have a gen 7 Samsung 8kw HP. I have solar panels which are dedicated to DHW via an MPPT Arduino controller. With the decent weather the array can easily heat what DHW we need so have tried to stop the HP topping up the cyl, also deleted the DHW schedule but I still get spikes like this, what else do I need to disable? Thanks
Hi @JPB,
I’m not sure TBH and you don’t say whether this is a one-off event or happens a lot. (Also, I don’t monitor, so I’m not sure of your colour scheme - I assume red is LWT, green is RWT), but for background information…
- The controller runs a wintersation cycle if the circulating pump hasn’t run for a while (per Samsung R32 ASHPs - when is a defrost not a defrost?) but this takes heat from the DHW tank, it doesn’t inject it.
- The controller exercises the circulating pump every so often if it hasn’t been used (I think it’s once per day, but this was discussed in a recent thread). This is most unlikely at this time of year of course, but if it does run it will move move a little heat around, possibly via the DHW tank if your 3-way valve is set up with DHW as default.
- On which subject, it may be possible that if you have FSV#3071 set to “DHW” the 3-way sits in that position until the controller demands space heating. You could always reset #3071 as a trial.
- The event at 04.50 looks like a classic defrost cycle.
Thanks for the help
Looked and 3071 is set to room, normal/closed so that looks right.
Looks like I didn’t have the correct settings enabled on the last screen dump, see revised, is this really a DF? Perhaps screen shot 2 gives a better picture and shows some DF cycles?
@JPB the defrost cycle I referred to was the event you show at 04.50, not the alleged DHW incident at 04.00. I only suggested defrost because they result in a LWT/RWT temperature reversal, and last about 5 minutes on my HTQ - may be slightly different on a Gen 7 - though the effects of a defrost cycle on the circulating water can last several minutes more (consistent with your displays).
For comparison, here’s a defrost on my HTQ (the defrost algorithm was in operation 09:44:12 to 09:49:31 according to the controller data*):
BTW on your expanded display, what colour is the DHW tank temperature line?
*Edit: I should add that the “defrost clear” signal was generated at 09:48:21, but the MIM-E03EN takes a further minute or so over housekeeping duties before it indicates “normal operation”.
Yes two completely different events but the defrost looks like what I have seen in mine and others so I assumed it was normal as has been discussed many times it was what looked like the DHW event I dont seem able to stop when the tank temperature is down a bit?
I dont monitor my DHW, the only thing monitoring it is the HP and solar, it would be better to add it to my installation but the tank pocket has the sensor for my solar setup as well as the HP sensor. so not a lot of room left?
Can I add DHW monitoring retrospectively? Preferably with a “skinny” sensor?
Answered my own question really as it was out of reach at the time, see below reply from Glyn.
Since you have an older version of the emonHP this is not compatible with the CT DHW sensor. If you wanted to add DHW sensing to your system, you would need to add our DHW retrofit:
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I could well be wrong but I think there’s a bit of confusion.
AFAIK the Heatpump app doesn’t have the facility to add a HW temperature field. What it does have is the ability to differentiate between heating mode and HW mode which gives CoP values for HW and heating separately. I think that sensor that Glyn is referring to is just a current sensor that report that state of the 3 port valve.
You’re almost certainly correct there.