Marvin

Hi @JohnMo Yes, need good insulation in narrow space so using PIR. Studs existing. breather on outside. True still thinking about 25mm PIR on inside.

Hi @Redbeard thanks for this Yes on the inside I am adding 25mm over the joists, then the VCL then the Fireboard. Forgot to say this is for a garden room walls. Hi @Mr Punter Thanks for the info.

Thanks @JohnMo I was also thinking about the dew point. I didn't know which way was best to instal them PIR to the outside and glass wool inside or vice versa.

I have a timber frame that I want insulate which varies in thickness from about 118mm to 155mm I was thinking of using 100mm PIR and loft insulation to fill the gap. Which is best: Outside surface, 100 PIR loft insulation Inside surface. or Outside surface loft insulation, 100 PIR inside surface.

Hi @MorganP This is a classic: Never have the cable going in at the top of the pump! The 4 Allan key bolts allow the motor housing to be rotated to any of the 4 sides and best if the cable inlet is at the bottom, BUT ONLY with the system drained or the pump isolated. I haven't read all the info here... Have you bled the pump?

I have never seen a green roof that falls towards a higher side of a building. I would try to find another way. At least falling away from the building and altering the drainage. It's even more of a concern when you consider that all the rain from the house roof in that area will also be draining there.

You couldn't think of anything simpler to explain then? 😂

This how my system is set and yes it heats up until the tank thermostat reaches the temperature set.

Hi @evekell A quick check to see if the bottom door seal is working is to pour a small amount of cold water on the outside of the door when it is closed and see if it goes into the house. I have done this with ours before now by using a COLD kettle and pouring a trickle about a foot from the bottom of the door, onto the door and frame, across the entire width of the door from the frame one side to the other. If the bottom seal is damaged it will leak If the door has been raised in the frame too high it will leave a gap between the bottom of the door and the seal and leak. This is a simple and easy thing to cross off the list of potential problems before doing any serious work. Good luck M

Hi @SteamyTea No smart meter. Energy used by ASHP goes through a separate meter first which only logs amount used. PV is already monitored to turn things on and off with CT clamps measuring the power to the grid. Extremely rare to supply power to the grid in winter even if PV working at full capacity. The Watt/hour level only peaks when doing serious cooking. Home background level is about 600w ASHP is in weather compensated mode and I wanted to see if the hot water is still adequate in lower temperatures.

Hi @SteamyTea Hope your well... This is the start of a test I am trying to do during the winter as this is the high use period. The heating is programmed to be on permanently and will be on until the spring (a few degrees lower in the night but still on) The hot water is programmed to come on when the tank temperature is below the 'on' until above the 'off' levels. the spread being 5.5°C, However I will stop that happening on occasions (when the outside temperature is lower than today, with no sunlight) to see what happens. You have made me think about it and I will record where the hot water temperature starts from in case it is below the level of 'demand' when it starts. Other poster had been discussing what happened to the house temperature when the heat is diverted to heating up the hot tank. I realised this would be affected by the outside and inside environment and decided to record the result when possible.

19/10/2025 8.30 am test: House temperature when heating hot water: During this test no major actions in the home were happening that would effect the results. Outside Temperature 11°C Weather no sun/raining/25mph wind - gusts to 30mph. Home temp 22.7. Hot water tank 205 litres Buffer tank 36°C Hot water starts calling The difference between hot water demand turn on and turn off is a rise of 5.5°C Hot water reaches temperature in 35 mins Home temp after hot water demand is 22.7°C Buffer tank 35.3°C Home temperature during 30 minutes after hot water heating finished stayed at 22.7°C In my opinion the time taken to bring the hot water tank up to temperature is suitable in duration (we are using low fan speed) and does not materially effect the home temperature when the outside temperature is 11°C.

Hi @JohnMo and @HughF Thanks for your thoughts. Yes I have lifted the sensor temperature to 42 degrees. However this is not the temperature of the water in the majority of the tank because of the sensor positioning. Reasonable hot water temperature and consumption in this bungalow. Thanks for your concern. Definitely over 45 degrees in majority of the tank when set at 42 and over 60 once a month.

This is the sort of thing that is my aim. I just need to adjust the ASHP controller to the right settings.

I cannot find the hot water set points so have adjusted the temperatures in the weather compensation section. M

My problem has been that the hot water temperature has been set at 40 but it doesn't actually kick in until about 36 which is too low. So on the odd occasions when the temperature is below 40 and there is shower demand the water is not hot enough. However because I have the system running on low speed mode it takes a while to reach 40 so rather than enter the weather compensation part I will alter the hot water temp diff to 2 and the stop to 2 and see how that works out. Unless anyone has a better idea.... Thanks Marvin

Hi @dpmiller I think I have worked it out. I use weather compensation so the hot water temperature is defined there.

Hi @dpmiller Yes I can bring it to user mask but then what? I have previously entered the engineers code but I cannot access U01

We have no app connection....

Hi @dpmiller Hi Its the CE-iVT9 and it's the set point? (to be clear - the point at which the water in the hot water tank rises so much that the ASHP stops heating the water in said tank)

Hi I need to change the set temperature of my hot water tank using the Carel controller. I have the engineering code but cannot find the location where you set the hot water temperature thermostat. Its slightly too low at present. Does anyone know the system well enough to guide me?

Also there were industrial scale trials. But look at the big scale and the fact that they couldn't easily regulate the output. https://www.pure.ed.ac.uk/ws/portalfiles/portal/8885379/Energy_from_Waste_Reuse_of_Compost_Heat_as_a_Source_of_Renewable_Energy.pdf The mix to obtain the warm reaction needs to be live. Mixing grass cutting, green (not evergreen) stuff and an amount of shredded sticks works quite well because of the mix of aeration, moisture and bacteria. I expect to start a pile next week and will supply info. I only use this as a way to produce great compost of garden waste. (not vegetable waste either!)

This is a subject I have researched and worked on in detail. The production of heat is caused by the bacteria reaching between 37 and 54 degrees centigrade with the right amount of oxygen and water. Far below 37 it just rots and takes ages. Far above 54 and it dries out and goes crispy. In huge commercial trials this has been hard to duplicate for several reasons. Although you can calculate the heat potential, controlling it, is nigh on impossible. Information, and my own trials, show that the mound needs to be at least 1 cubic meter and live material. Yes the compost goes better in summer but you can insulate around it in winter, but then it can over heat and the bacteria dies. Also it needs to be mixed correctly.

A concern would be the starting up of the ASHP if it was frozen. I think you may have to wait for the compressor to warm to above 5C before you should start it otherwise is causes excessive wear?? I think that is for 12 hours continually above 5C. I think that's why the ASHP circulates at night and has a heater (warmer??) in the unit that comes on in cold temperatures?? Well that's what I understood.

That makes 2 of us. Also there is a slim chance that the place freezes up, power goes down and 10 thousand ASHP's go pop at the same time and I will be the last on the repair list.