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Ambaz79

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  1. Forgot to mention I've got a 100L buffer tank.
  2. If I reduced the flow temp to maybe 37 or 38 then would we expect a cycle less often. Ideally would like it to run more constant as we have the UFH in thin layer of screed at around 60-70mm and this means it does not retain much heat for long. Slab just about warms up and then a cycle where it cools the slab down again due to the UFH still running. Should the UFH actually still be running during a cycle. I do notice the supply to manifold does get cool during cycle.
  3. Thought I would start a new topic as my last post focused on my dhw tank loosing heat very fast. Solved by the members here and a bit of detective work. On another subject I'm noticing my hp is cycling around twice an hour. Running in weather compensation mode with the following. Low is 40 Degree Flow at -1 Degree outside High is 25 Degree Flow at 15 Degrees outside External thermostats in every zone set to 30 degrees and rooms hit around 20-21 degrees. Flow on manifold is slightly higher then the designed flow at around 1L per minute to around 1.5l. I've tried to increase flow to 3L but it's still cycling. Outside tempreture is currently - 2 in Leicester so we expecting it to run more without having to shut down. Is there anything I could change or look at to reduce this cycling.
  4. Turns out my son was going for a shower for over 20 minutes after school. This was emptying the tank. I've kept the Circulating Pump off and might just remove it. I've set the tank to warn once at night and once in the day. Also restricted my sons shower to less than 10 minutes. Not sure this is being fully followed though! We are getting through 24 hours with just 2 cylinder head ups. Thanks for all your help on this.
  5. Yes there is that is lower down the tank. You might just be able to see a small wire going into the tank.
  6. Looks like there is some other problem. Circulating Pump been off all day. Left at 8am with water temp at 49 degrees. Target temp was set to 48 degrees. My son went for a 10 minutes shower at 4.30pm and then we have used it for washing up after dinner at 8pm 5 minutes into washing up the water went cold meaning no hot water in cylinder. I would expect a 320L tank to do allot more then this on a single charge. I've had to change the ashp dhw to come on on a 10 degree temp drop and left it to be constantly on. Could it be the Cylinder is not fully filled up. I thought it could be loosing water somehow but then thought we didn't use the water all day and water has remained hot. But lost with this now.
  7. Looks like there is some other problem. Circulating Pump been off all day. Left at 8am with water temp at 49 degrees. Target temp was set to 48 degrees. My son went for a 10 minutes shower at 4.30pm and then we have used it for washing up after dinner at 8pm 5 minutes into washing up the water went cold meaning no hot water in cylinder. I would expect a 320L tank to do allot more then this on a single charge. I've had to change the ashp dhw to come on on a 10 degree temp drop and left it to be constantly on. Could it be the Cylinder is not fully filled up. I thought it could be loosing water somehow but then thought we didn't use the water all day and water has remained hot. But lost with this now.
  8. Yesterday night I switched off the Recirculating pump and the water cylinder has kept a stable tempreture overnight. Almost flat lined at around 47-48 Degrees as I changed the water target temp to 48 degrees. Only thing I noticed is in the morning when the 1st shower was taken the water did drop down to 20 degrees in the app. My Water Cylinder has 2 places where we can inset the thermometer and its currently in the lower one. Im guessing the reading is from the lower part where it takes in fresh water thats cold. I had it set to reheat the cylinder when it drops 10 degrees lower then the target temp and to heat for a maximum of 120 minutes so by the time we went for the second shower the reading was back at 48 degrees or slighly over. What I have done this morning is put it back onto schedual to heat the water at 2.30am for 2 hours max. It will be interesting if there is enough water to last a day or will I have to have it come on for a few hours in the day too. I have 3 Teanagers so showers are a bit longer sometimes then 5 minutes. On the negative side it now takes allot longer to get hot water when we turn on the tap in the ensuits that are around 14M and 30M away from the tank. Kitchen is even further in the run at around 40M ish. This is why a re-circulating pump was chosen in the first place. If this was the cause of the problem then is there any other solution to this? Pump does not have any other settings other then run at 100% all the time, Run when the water temp drops in the pipe line or adaptive auto where it uses algorythms to know when we will be calling for Hot water and circulates the pump at around these times. Pipe that makes the circle is not currently insulated so I can insulate them. but not sure if this would really solve the problem overall. also on the point of stratification, does it not move around/mix the water when the fresh water is pumped into the cylinder anyway as hot water is called for?
  9. Sorry made a mistake on my Tank Size. It’s actually a 320L Unvented Cylinder with a 25 Meter Coil pipe inside. It’s also got a 3kW Emersion heater that’s on a 2 week cycle for Legionnaire. What I did last night is put the water on Cycle to heat at 2.30am to 3.30am and the setting was on Eco. Apparently it means it heaters the DHW with a lower temperature making it more efficient but taking longer to heat. 6am my wife went for a shower and after this the temperature just goes down and stays down. I went for a shower at 8 and it was luke warm water. Maybe 20-30 degrees. So at 8.45am I turned off the timer function for the DHW and went back to it being heated as the tank required with the setting to heat after a 20 Degree drop in tank temperature. DHW is now set 49 degrees. Only other bit of info is I have a hot water circulating pump. Its set to monitor the temp in the How water supply pipe and circulate it if the water get cooler. I don’t know if this is making any difference. Grundfos UP 15-14BXA PM GB Brass Comfort Hot Water Circulating Pump. I still don’t understand even though the water heated to around 40 degrees and the shower was only used once for around 5-7 minutes why the tank had no hot water at 8am? Does not make sense to me. For my heating I have now reduced the flow in the manifold to the rooms and increased the weather compensation curve slightly to increase water temperature for heating. I read somewhere that if the flow is too fast and water in and water our is similar temperature then it would stop the HP. Yesterday I was seeing the HP cycling around 4 times per hour. Today I see its Cycling around twice an hour. The ideal scenario would be that we stop this cycling. Heat Pump is around 7-8M awy from where the Cylinders are and the pipes to and from the HP are insulated. Other pipes connected to the Cylinder are not. I will try and take a picture later on tonight.
  10. on the screen shots attached we leave home at 8am so after this point no one should be using any hot water.
  11. We have a 200L tank and there are 5 of us that live there. Would it be ok to set it to a 1 hour window at night. Im guessing I can answer this really by setting it like this for a few days to see if we run out of hot water?
  12. Hi Gary Totally makes sense now. I am surprised how fast it shows the tank tempreture drops. In the graphs it looks like every now and then there is a 5-7 degree drop in the water cylinder within the space of 20 minutes. Does this look normal. I would expect for a tank to drop but very slowly as its very well insulated. I will set a better schedual on the control panel and see how this makes a difference.
  13. Hello All I have an Ecodan 8.5kW Heat Pump with a 200L hot water Cylinder and a 100L Buffer Cylinder. I am using the HP in Weather compensation mode and when I check the hourly tempreture in Melcloud it shows the Flow is fluctiting allot. Settings for the Wether compensation are as follows. Low is 40 Degree Flow at -1 Degree outside High is 25 Degree Flow at 15 Degrees outside This morning the outside temp was around 8 Degrees so I would expect the flow to be around 30 to 32 Degrees however it looks like it runs at around this level and then keeps spiking to over 50 degrees. I am sure this means we are using allot of electricity. I only have the UFH downstairs and have Rads in the 3 bathrooms upstairs that are oversized. bedrooms dont generally need heating but we have AC in every bedroom that we use for heating if needed. Downstairs I have Thermostats in every room and they control only the manifold. Thermostats are set to a few degrees above the target tempreture. House is fairly air tight with triple glazed windows and 100mm PIR Insuration in walls all the way around. loft roof is also very well insulated. Is there something wrong with the settings or is there the weather compensation curve now correct?
  14. Hi @JohnMo Yes to be honest it was a bit of a DIY attempt and although I did get allot of advice from the forum aswell as the factroy who supplied the unit I would agree its not been designed to a specific standard. I dont need any certificates as the house is already signed off and there was no requirements for me to provide any certificate of caliberation. I just need to get the system set so the house is comfortable and healthy to live in. So if I look at the table you have sent then I would go with the 4B'rm./ 5P: 90m3/h [25 l/s] and set the extract as mentioned in the table too. How do I acheive the air exchange rate? how does this effect the calculations above? Also is the Air Exchange rate actually set at the supply and extract that is measured directly from the actual MVHR Inlet and outlet. The house is around 400 M2. Your right I could be overcomlicating this!
  15. In all honesty I am a bit lost with this. Apart from what I have sent across in the oiginal post I dont have anything else. I thought with the above info someone should have some sheet that could work the rest out once the room sizes are inputted. I could be wrong though!
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