I also see frost protection running every hour on my
Samsung HT 8kW installation…
It takes the heat from the house CH, if available, for just a few minutes, I presume by running in a reverse heat cycle. I always leave CH on at night now but with a set back to a low temperature. If there is no CH available then it takes it from the DHW. The DHW will only run for a maximum of 90 minutes anyway so best turn it off after an hour or so and run it twice if necessary.
On the point about maximum DHW temperature - I did a test and found that the LT for DHW rises over an hour to 68degC pretty impressive see photo so the HT of 70 degrees claim of Samsung seems to be correct. The target temperature max is naturally lower and seems to be 55 degC but you can locate the sensor where you like for best effect.
Interesting that the controller settings do not seem to be able to change the temperature rising to such a high maximum only the target temperature. I understand you can avoid this by running half hour DHW sessions which would be more efficient if you can tolerate lower water temperatures.
I have a pre existing UK standard 240 litre indirect tank with a coil at the bottom and it all works just as it did with the oil boiler so I am pleased with it…
Just before the hourly defrost
