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AnRam

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  1. I have now fitted the delay timer as described above. It does what I require, but the thermostat effectively has no hysteresis, so is a little enthusiastic to turn the HP on and off to maintain an exact temperature. I am continuing to look at alternative thermostats.
  2. True, but the water temperature is always low because the pump is being cycled on and off, it never fully heats up
  3. I would prefer a combined temperature and timing control, wireless device. Thanks
  4. Thank you all for your comments. I am very concerned that my Heat Pump Supplier is providing this unsuitable type of Thermostat. I have asked them why, but have not had a response. I have thought out a simple 'defeat' mechanism for the existing thermostat which consists of a delay timer that has a delay slightly longer than the 'on' cycle time. (the cycle time can be set to 12/hr so the delay can be as short as 6 mins) The delay timer will switch on the heat pump so when the thermostat is more than 1.5 degrees below demanded temperature (on continuously) the HP will be run after 6 mins. Once the thermostat is within the 1.5 degree limit the delay timer will prevent the HP being run at all. To make this practical the thermostat will need to be set 1.5 degrees hotter than is actually required. A crude solution, but it will make more sense till I can fix it properly! In answer to your comment, ProDave, I agree that Honeywell make no useful reference to the 'feature' but if you look at the Quick Installation Guide under 4, Parameters, you will see listed a setting 2CR which is the cycle rate with no other information about its use! I have spoken to Honeywell who agree this feature exists and cannot be disabled. Helpful Huh! I am amazed that professional installers appear not to be aware of this issue and that there is no obvious Heat Pump friendly thermostats. If anybody knows of a suitable Programmable, Wireless, 'Dumb' thermostat I would love to know.
  5. I have recently had an LG Therma V monoblock 16KW Heat Pump installed. It has been fitted with a Honeywell T3R thermostat. It appears this thermostat has a cycle 'feature' When the room temperature is within 1.5 degrees of the demanded temperature the thermostat goes into a boiler cycle mode. In this mode it cycles the boiler on and off a preset number of times per hour. When installed, the setting was 6 which means the boiler is on for 5 mins then off for 5 mins (6 times/hour) On this heat pump this serves no purpose as the pump takes more than 5 mins to start hence power is wasted while running the circulating pump to no effect. If the thermostat cycle time is set to 1, as described in the installation booklet, then the boiler is on for 30 mins and off for 30. This at least allows the heat pump to start and run but due to the slow warm up has little effect before it is switched off again. I can see the cycle time might work for a gas or oil boiler to maintain a background heat level, but with a heat pump all it seems to do is waste energy! When the room temperature is more than 1.5 degrees below the demanded temperature the thermostat switches on in the normal manner until the demanded temperature - 1.5 degrees is achieved. In practice this means that the thermostat temperature has to be set 1.5 degrees above that desired as the cycling of the thermostat largely achieves nothing except wasting energy. Has anybody any suggestions for a 'non cycling' programmable wireless thermostat or will the HP accept a modulating thermostat?
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