Hi All , hoping you can help explain what’s happening here. Newly installed Samsung Heat Pump Joule Kodak 150L DHW Tank. When the DHW is heating up in the Summer time the DHW Temperature can drop from 40 to 30 degrees before starting to heat up again to 45 Degs although the tank does hold it Temperature well in the summer months, why is the DWH temperature dropping so much ?
Now were in the winter i’ve noticed the DWH Temperature drops down maybe 2, 3 times a day depending on the outside Temperature to reheat the tank, this happens after the water has been heated up to 45 Degs in the morning and no draw of water off during the day while at work. in fact the higher temperature i heat the tank the quicker the DHW temperature drops hence why i’ve it set at 45 Degs.
I’ve enable an on / off schedule on the DHW to prevent the DHW coming on so often this actual works around the 5 Degrees target drop to disable the DHW running so often but is this the right thing to do ?.
This depends on your set-up (the physical layout, and your DHW heating settings). What you are seeing may be no more than a little temperature layering in the DHW tank (which in general they are prone to do, though I can’t speak of the Joule-Kodiak specifically). If just a little hot water is drawn off, and the temperature probe is near the bottom of the tank, then the cold water that enters may affect the measured temperature (while most of the tank is still hot). If you have set your DHW heating to, say, only once per day for an hour, the tank will sit there with cold at the base, warm everywhere else, until your next heating session.
There are a couple of controller algorithms that run in the background (and there’s not a lot you can do about it).
If your circulating pump hasn’t run for an hour, and the outside temp is below 5degC, the circulating pump will run for a few minutes, via the DHW tank coil, to make sure that the outside piping doesn’t freeze. This results in a temperature drop in the DHW tank. Have a read of Samsung Gen6 and anti-freeze pump cycling below 5C OAT for an animated discussion on the subject.
Also, if the circulating pump hasn’t run for 24 hours, the controller “exercises” it for a few minutes to make sure it hasn’t seized (though I forget whether this is via the DHW tank coil or the emitter circuit).
Finally, there are defrost cycles. These take heat from either the DHW tank or the emitter circuit, depending upon which was in use at the moment the defrost cycle started. See Samsung R32 ASHPs - when is a defrost not a defrost? for further explanation.
I do hope the above doesn’t confuse you further (or try to teach you to suck eggs…).
Thanks so much for the above information it was really useful and I am experiencing exactly what everyone else is. I spoke to Joule here in Dublin about it they said it’s. Normal given the temperature stat in the tank is half way down and the top of the tank will still be warm/ hot not ideal .
I stick with my DHW schedule and leave the defrost cycle to run every hour
I assume there has been no fix from Samsung yet I.e frameware update