Ultima357

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  1. Normally there is some mixing of the supply temp to the UFH by buffer tank giving a lower input to the UFH. You can run the UFH at 50 but it uses more energy. With a mix of radiators and UFH and without separate heating control/circuits you are juggling. The system designer should help you out if it's a new system. Basically I'd imagine that your ASHP has a set water out temperature which feeds both rads and UFH so to get the best performance the system should either have oversized rads that can run at a lower temperature or some mixing to lower the UFH feed. UFH is normally set between 35 to 45 deg. If no system designer help is available then try setting the water out temperature back to 45 deg and see how it all performs. If all is well, then try lower still. It is normal for the ASHP to have weather compensation or water law as some call it whereby it increases the water outlet temperature in colder (Eg near freezing) weather.
  2. Those figures are complete nonsense or it indicates something seriously wrong with the unit/installation. Extract air temperature should be roughly the temperature of your wet rooms , say 21 to 22 deg. Exhaust air should be lower, and how low depends on the external incoming air or outdoor reading in your display. Supply temperature should be only a degree or two under your room temperature as the heat exchanger does its business to warm up the outside supplied air temp which in turn cools the exhaust temperature. My Brink at 10 deg outside is currently supplying 21.7 fresh air. House is running at 22 generally but 23 in ensuite and kitchen warm after evening cooking. The Brink gives volume flow rates for both fans so I can see what is happening.
  3. They do, or at least my Samsung one does, BUT, and it's a very big but, the figures it gives are pure fantasy. Actually a work of fiction and completely useless as it claims a COP of 20 at times. 🤔. I've asked the question to Samsung but still waiting for an answer.
  4. No that's figures over a week or more.
  5. What does passive actually mean? There's a technical standard defined by the Passive haus institute detailed above which you can go for but that's just a vanity £5k spend on a certificate. It basically entails the level of insulation/heat loss and airtightness of the structure. In mine, its 300mm insulation in the walls plus 35mm dead air gap, 400mm in the attic, 300mm XPS under the floor tapered to a minimum 100mm at the dpc edge (so totally enclosed foundations) and triple glazing. All airtight to a measured 0.17ach @50pa. In heat loss terms of U values, walls are 0.1u, roof 0.1u and floor 0.12u. All windows/frames better than 0.8u. A 1930s cavity wall? Well the cavity is likely to be small, so I'd guess the u value would be around 0.5u. My running costs in the past freeze, 15th of Jan to 15th of Feb for heating and hot water around £65. £2 a day. Whole house at 22 to 23 deg plus warm attic circa 85m2 too. 14 zone UFH cast directly into the slab, 155ton heat store. Around 1.5km of pipes! 400l hwt
  6. They do, or at least my Samsung one does, BUT, and it's a very big but, the figures it gives are pure fantasy. Actually a work of fiction and completely useless as it claims a COP of 20 at times. 🤔. I've asked the question to Samsung but still waiting for an answer.
  7. Flow rate in a ASHP is likely to be around 20l/min. Should say in the handbook /installation instructions. If just a straight replacement, it looks like you have a single circuit and by the time it gets to furthest point, the temperature is too low to heat the house. ASHP typically run at 40 to 45 deg, an oil boiler at 60 or more. And of course, oil fired are overrated to cope with the extreme demands. A 12kw ASHP will only raise a flow rate of 20l/min by 5 degrees so if your circuit is dropping by more than this in cold weather the furthest point is not going to get warm. Get the installer back and ask him to prove his heat loss calculations.
  8. If you have Heatmiser Neostats, simply set the overnight to 5 deg lower than daytime. Even in a poorly insulated place you'd be unlikely to drop this much. I'm guessing that as you have ASHP then you are decently insulated and draught proof. Not heating some of the house as high as the rest will save some pennies but if your internal walls are not insulated, a cold one could attract moisture if the temperature in these is too low. The cost difference between 10 and 15 deg is not huge and bear in mind that insurance policies usually have a minimum temperature required around the 13 to 15 mark if you're claiming for frozen pipes.
  9. On the PV front, in winter it obviously generates less and as the ASHP will be running, you are unlikely to get much input to the immersion. Summertime yes and plenty of it if you have a decent PV array facing south. You haven't said what your EPC score is and that should come with an estimated heat load if you got a full one. Size of the property is a factor too but I think that ASHP will be an expensive option for heating. I'm running one in a new build passively insulated home (3 to 400mm insulation and triple glazed, mvhr etc), 253m2 and it's rated at 12kw. It copes even in the recent freezing conditions but they all ice up and COP is circa 2 at freezing fog temperatures. My EPC score is A98. Good luck. PS See the Cost of Electricity thread elsewhere on ASHP running costs in a renovated property.
  10. According to the manual I found online, the display should have AR displayed to indicate remote air sensor or FR for floor sensor. If your bathroom one has just A then its on its own sensor and wrong. To change press M for 3 seconds and then use arrows to change and tick to accept. CS17-touchscreen-programmable-thermostat-Installation-guide.pdf
  11. Don't know what stats you have but my bathroom ones have the head outside and the sensor inside. The stat has to be set to monitor the remote sensor as they default to internal sensor. All three of mine were not properly set up by the installer.
  12. Yes they modulate fully. Anywhere from around 1kw to the maximum. In my experience it'll pull up to 4kw (possibly a little more) when hitting the higher temps for water heating and close to this for UFH. Just judging by the figures on the smart meter gizzmo and deducting our normal run rate of 4-500w.
  13. Calling all owners of Samsung Gen6 ASHP (maybe others too). I have found on my system that when the exterior temperature drops to 2deg or below, if the pump is not working for heat/DHW, it enters a frost prevention programme where it runs the main circulation pump and operates the DHW valve. This means it is sucking heat out of your hot water tank to prevent the external unit getting the shivers. Quite why is the good question when mine and I suspect everyone's is filled with antifreeze protector. We've posed the query via our contractor to Samsung as the contractor is as puzzled as I am as to why it should do it. I discovered this by accident as I set the internal overnight temps back a degree or so at 22:00. One frosty night walking past the kit cupboard at 24:00ish I heard the circulation pump running and discovered this. On a fully cold night it takes around 8 to 10 degrees # out of the hot water tank (400l). I've now bypassed the DHW valve with a switch so it pulls it out of the buffer instead whilst we wait for Samsung to reply. Note the pump runs several times a night for around 5 mins a time. #We're passive insulated and EPC A, so room temps barely fall a degree overnight. It seems mad to me to have this put in the programme with no way to adjust it. If it could be set to only do when say the outside temperature falls towards the freeze point of your mix then fine, but otherwise this is just wasting heat.
  14. I have 14 individual zones, so very controllable. We run at 22 to 23 degrees during the day and set back to 21 overnight. Like you, I find UFH not very responsive but then again mine is cast into the fully insulated floor slab, so 155 tons of concrete heat store and generally the pipes are in the middle of 150mm thick slab. So I guess it can't be that responsive. We rarely lose more than 1 degree overnight (22:00 to 07:00),so guess its not going to make a huge difference.
  15. Do you think its better to run it 24hrs rather than as I do, which is to leave on but set it back a degree or two at night? With our passive construction, it doesn't come on at night. In the morning I bring in the zones as needed over a couple of hours or so, so that it doesn't suddenly get a huge heat demand.