From a quick look back it looks like your high flow temp issue occurred 7 days ago, along with the time which it started this morning being out with your normal schedules, this suggests to me that it may be trying to attempt a weekly legionella cycle? What temp is your DHW normally set to and do you know if it was much hotter out the tap this morning?
Did you get anywhere with arranging a visit from a Samsung engineer? If you’re struggling getting this arranged through your installer then you may have more luck going to Samsung direct and explaining your issue.
I agree that monitoring equipment would be the way forward, with at least temperature probes and CTs both connected to an emonBase/ emonTx. I have a combination of sensors in pockets and sensors strapped to the pipes and don’t find them to be vastly different in readings, the pocket sensors will be more accurate but are more expensive. Ideally you would have a heat meter to accurately measure the COP, but this can get quite pricey
I have also become convinced that the Over-temperature problem is caused by the Hot Water cycle.
The problem is that the Legionella Temperature is set for 60C for a maximum time of 1 hour.
As I speak the Heat Pump is still stuck in Heating the Hot Water from the outdoor unit in my garden.
The Hot Water temperature is above the set , demanded, temperature of 50 C but the Heat Pump is still stuck in supplying electricity to the Hot Water system!
I have now forced the Hot water Temperature down to 45 C , and, mercifully ,the Hot Water cycling has stopped!! Return to sanity!
This may not be legionella misfiring it could be the standard Hot Water system not stopping at the upper tank Temperature temperature. The Hot water Tank Temperature sensor?
Many thanks Colin , you have made me experiment and think!
What your graph says is that the HP flow temperature is 55 degrees, not that the hot water temperature is 50 degrees. The sensor in the tank could be reading 50 degrees, so the HP thinks the tank still needs more heat. Can you access the temperature as read by the sensor? Could you graph that against the HP flow temperature?
Getting an Engineer has proven to be another nightmare.
I asked the original companies who quoted for the installation to quote for repairs or upgrade.
One company quoted a price “without Warranty” or a price of £5k with warranty. The company demanded £96 for their advice. No thanks. .
A second company, wanted to entirely remove not only the Heat Pump but the pipes and the Radiators, saying that the radiators and pipes were too small. An excellent company but no. !^K is too much.
The third company proclaimed that “i Was to blame for choosing these cowboys”.
The Engineer of the third company had two groups of letters after his name, pretending to hold Learned Society membership. The Learned societies turned out to “City & Guilds”. Again , no thanks.
I am in no doubt that the only people who can fix this are Samsung and Telford.
I have twice been promised a visit from Samsung, but, my Installer described the Samsung bill for travelling from Wigan for three days as “ludicrous”.
As to the problem with the Heat Pump It looks like the Hot Water was called , increased the water temperature but failed to stop reaching 65 C without protest.
It looks like the Hot Water thermostat this time.
My previous problems with the Weather compensation, were also probably caused by the air Temperature Thermistor. The Weather compensation seen to rise and fall unexpectedly.
A case of too many thermistors!
Many thanks for your help. I am getting tired, after 8 months of heat pumps.
I don’t think you can get the elec consumption - but you can get a bunch of other stuff including things like compressor frequency or similar data. See this thread. I have some other renovation jobs to focus on this week (thermal solar, and waste water heat recovery for the shower) but will get back to the modbus stuff soon after.
What’s the capacity of your heat pump and diameter of the pipes? Your annual consumption figures sound like a 5kW heat pump and heat loss? but Im not sure if that’s correct/established? I’d expect 22mm primary pipework at 5kW, I think Samsung may even recommend 28mm for part of the primary pipework even down to 5kW, but 22mm should be plenty (mine is all 22mm primaries for a 5kW heat pump, radiator connections all T off with 15mm pipes, all copper).
Both of these issues sound like either control setting, circulation pump control or temperature sensor issues. A samsung engineer should be able to get to the bottom of the right configuration for your system.
Could you clarify as well your radiator TRV settings? How do you use the radiator TRV’s? are they all off apart from used rooms? or all on a low level e.g 1-2 or all on max? How many radiators do you have and what kind are they? single or double panel? If you do have time could you list all the radiators in your house, with dimensions and type and how you use those radiators e.g TRV off, TRV 1-2 / max etc?
On our HP, the DHW and Heating have two settings to control when the pump starts and stops. So there is a temperature differential, i.e. when to start and a stop temperature difference. On the DHW side of ours this is set to 0 but it’s set to 2 for the Heating, so when heating the pump will overrun the set point by 2 degrees. Does the Samsung have similar settings and if so could this be the reason for the overrun?
The other reason as @TrystanLea pointed out could be a sensor issue. We had this problem initially. The sensor for the DHW had a bad connection, so the HP was getting a bad reading. The sensors for ours are PT1000s, so any additional resistance from a bad connection gives a false reading.
What was happening due to this, was that the HP thought the DHW wasn’t up to the set point, so kept running until it reached it’s maximum which is around 65 degrees, throw an error, stop for a while and then repeat.
I cant quite see that picture clearly but that’s likely a system without a heat exchanger. It is indeed normal for a buffer or low loss header to be installed in parallel in systems without heat exchangers. The buffer is effectively providing the equivalent (hydraulic separation) function as the heat exchanger is on your system. To have both seems strange to me…? a volumiser in series with the heat exchanger would make sense as it would reduce cycling in the event that the secondary side of the heat exchanger is not loaded. You should however seek advice of a professional heating engineer, Im just an enthusiast householder really when it comes to heating system design giving my 2 cents from what I’ve learnt so far.
The Samsung config and documentation is VERY confusing. It might as well be in Latin. I have been extremely careful when changing those settings. You may want to share ALL the settings within that section for DHW. I can compare with mine.
Correct, that is what we mean by hydraulic separation. A heat exchanger is typically fitted to allow glycol to be used in the primary circuit for freeze protection and water only (+inhibitor or other protection) in the secondary water that goes around your radiators. I’ve just given Telford technical a quick call and they dont seem to understand either why the buffer is in parallel and agree that a series connection would make more sense (they dont typically install a buffer or volumiser alongside a heat exchanger - at least with more recent samsung models where defrost energy is extracted from the hot water cylinder rather than the space heating system).
I think the buffer is only one factor of several that need looking at with your system. The controls and what is happening on the radiator side may be of greater importance… I asked about your radiators above, could you clarify what you are doing on the radiator side?