Hi. I’m new to this forum so apologies if this is going over old ground.
I’ve been wrestling with the frost prevention cycle ‘stealing’ hot water since my Samsung heat pump was installed 3 years ago.
My installers argued they had installed the system as specified by the manufacturer, and couldn’t help, so I contacted Samsung tech support. After an exchange of emails, this is the key part of their response:
“This is the way the anti-freeze logic works.
The system needs to pump heat from a part of the system during this logic and its fixed to use the DHW cylinder, the reason for this is that there would generally always be available heat in the cylinder to ensure the cycle completes. If the system took heat from the heating portion of the circuit is some situations, with poorly applied systems and low water volumes the antifreeze logic would use the residual heat available. If the circulating water temp drops below 20C the heat pump will not have a safe condition for prolonged operation, which would lead to a lag in response the next time the heat pump was called for.
The logic does call for a backup heater to energise when this logic is carried out which, if you had one fitted would, I imagine reduce the temp drop on the cylinder. However in the UK most installers opt to not use a backup heater, also if you did have on it could lead to slightly reduced efficiency as an inefficient back up heater would be turning on periodically during the cycle.”
For most of the year, the ‘anti-freeze’ logic isn’t a problem for me, but with the recent cold weather it’s been an absolute pain. I heat the water overnight on a cheap Octopus tariff, and that gives enough hot water for the full day. The antifreeze logic quickly knocks much of the tank from around 50c to below 40c (what’s needed for a shower in my view), so leaves me with insufficient hot water unless I run the system to heat it back up.
I’m currently wondering if anyone has found a way to fix the issue? A firmware update from Samsung would be my first choice (there has got to be a better way of doing this), but they don’t seem interested - although I’m quietly hoping they wake up to this as increasing number of customer work out what’s going on and complain! My best idea at the moment is to fit a 3 port valve so the flow only goes through the hot water tank when it’s set to heat up. Any other ideas?