Carpe Diem

Hi, I have an ongoing issue with the ASHP on a property I've built. In summary, we have a passivhaus c.450sqm with an 8kw ASHP, underfloor heating throughout. The ASHP was installed by Magna Renewables, and it's now got to the point that NICEIC have had to step in, and I'd like some independent advice as the installer hasn't resolved. We have 3 main problems. 1.Soon after install the energy usage was really high. Much higher than estimated. He is blaming Loxone because we have thermostats in each room and his view is that if it is calling when a single room cools, it is short cycling. Fair enough, but his solution is to remove loxone and have a single thermostats for the entire ground floor and one for the first floor. This doesn't work for me as a solution as we want individual control. There is no buffer tank. There is a low loss header. My (uneducated) view is that buffer may help resolve the issue as it would stop a small top up demand causing the ASHP to run. We have a 300l tank for hot water. Any thoughts? 2. Since the engineer last visit, we have to keep tipping by up the tank as the pressure drops. Takes about a week to go from 1.7bar to 0bar. He is saying he will put leak stop in the system as we can't see any sign of leaks. This is after I turned off the valves to the UFH and hot water return, which he was saying is where the leak most likely was. I turned them off because I was panicking we had a big leak in the UFH so I figured if I turned them off, and the pressure stopped dropping then this was the cause. But it carried on, so he has now accepted it is in their install (somebody else did the UFH and hot water in the house). Will leak stop work? Where is the leak if we can't see it? Is leak stop a bodge? all pipes are in ceiling and its been ongoing for over 6 months and no wet marks. 3. Every so often we have no hot water. When I check, the immersion heater is running like it is doing a legionella cycle but that's been turned off. The immersion says it is in but the tank keeps cooling. My suggestion is the element isn't working but he says he has checked power and it's fine. Note "power"..... he hasn't checked the element is working. anybody else seen this? Thanks all!

But that then means that if, for example, one room is calling for a tiny amount of heat (2% valve open) that the heat pump runs. What I am seeing from the Loxone app is that the heat is called for frequently in small amounts to maintain the temperature of the slab, which I presume helps with efficiency. But, is this not bad when it keeps calling the heat and short cycling it?

Yes, TLA's are the devils work. I have attached a pic of the black unit. Not good that it adds inefficient. Any suggestion on how to change this or how they could/should have done? He definitely said that it does not take the heated water from the HW cylinder so it must have an emersion heater in it. They are going to look at introducing a small cylinder just for the UFH but he said to wait and give it a few weeks or months first and see how we get on. By which point... winter will be over of course so no heating likely. Ref the CoP and curve; he said to start it off as recommended and if the house is warm..... reduce the curve every few days. Generally, I tend to find the house is too warm in the bedrooms in the bedrooms of an evening.

Ok, so the company that installed have visited today and found several things out and also made some changes. He wasnt sure what UVC or OP stood for???? The UFH does not pull hot water from the HW tank. There is a separate vessel next to it, small black unit about the the size of 8/10 litres, that circulates and heats the water for the UFH. He found that the top up valve had been left open, so the tank was getting topped up with cold water.... wasting the hot water. The pressure was at 2.4bar, which he said is high, but must be the pressure at which the water into the property is at, otherwise it would continue to increase. Seems low pressure to me, but that is what he reckons it is correct. He adjusted the compensation curve and set the tank temp to 50c, whilst changing the control unit so it now shows energy consumption. At -3c external temp the curve is set at 40c. At 10c it is set at 32c. He reckons to try the HW running on a schedule of a few hours in the morning and a few in the evening, to see if that is enough for the usage. Outside of those hours it will use the tank hot water, which will obviously cool throughout the day. Any thoughts?

Not sure how we could retro fit that, but it would be good to have a motion sensor at floor level that brings on the night light on the switch.

We have Loxone control the blinds, MVHR etc. Its fully automated throughout, so I was hoping the issue with the heating cost was largely due to ASHP not being configured correctly. However, I now think that it may be a fundamental issue with the system specified. When the UFH is called even a tiny amount it seems the ASHP kicks in 100% so its costing £100s of elect on ASHP to heat £1s of space. I could change Loxone so that the heat isnt called until the temp is called in (for example) 2 rooms, or % open is 50%, but that could be false economy if it then takes x10 longer to heat the space. Any suggestions? How can I check if I have a UVC v OP (no idea what that actually means btw)??? Ref Loxone and confusing guests....Triple tap we have for night move, but its not common to tell someone to do this. When its night and the switches arent illuminated (we dont have the glow light on next to the beds) it can be confusing for a guest to press the switch and one of the corners and bring the radio on or open the blinds. Its not the end of the world, but in IMHO... it looses some of the premium feel when people are confused. Everything else is on motion sensors, which people like. Still prefer to an overly confusing C4 interface... but thats just my experience.

Hi, We have recently completed a project that is Loxone and Delta Light throughout. Most of the circuits are Dali. We have an issue where some lamps have a residual glow, which I understand is common and easy to resolve.... except we dont seem to be able to resolve it. We have 2 main areas where this is an issue and one is really strange. 2 Issues: 1. We have 12 lights in a double height hall way, all wired the same with one driver between 2 lamps. 6 glow and 6 dont, yet they are all the same lamp, same driver, same settings. Any ideas? 2. We have 3 lamps on a single driver. With one lamp it is fine, we put 3 lamps on and it glows. These are easy to access as they are in the ground, so we put a tester on it and there is still 1.5v through the driver even when turned 0% on. Delta Light has said to include a 27k restistor. We did that and no difference. We even put 3 in series and no dimming at all. Is this an issue with the Dali module from Loxone, the driver or the lamps both from Delta Light, or something else?

Loxone is pretty good for the lighting and heating from my short experience. The media side of things I have not been impressed with, but my biggest mistake is the HDAnywhere setup, just seems pointless and cheaper to buy Apple TV's in everyroom. The main challenge we have is getting others used to Loxone, e.g. when guest stay over. Talking about night mode and tripple tapping, compared to say a C4/Lutron with a nice labels switch on the wall...... its confusing.

I have tweaked it down a bit, and what we can do is write a command so that if it is only one room at 5% it doesnt call. We could delay it so that it has to be 2 or 3 rooms calling, or a greater difference.

I have 2 x Q350's. Currently, they both have 43w being used. Year to date 36kWh. The usage is pretty low compared to what the ASHP is using.

Pros and cons though.... we dont have to worry about the temperature in any rooms and have no hot or cold spots. In another house we have it setup with one zone and its not great if doors are closed etc as we basically have to set the thermostat to 23C in the hall, and know that then means the bedrooms off it are near 21c. When its a sunny day, the room at the back that gets all the sun over heats, because the hall is in the shade so it is not externally heated. At least with sensor in each room, we have all the rooms perfectly balanced to the same temp.

Pros and cons though.... we dont have to worry about the temperature in any rooms and have no hot or cold spots. In another house we have it setup with one zone and its not great if doors are closed etc as we basically have to set the thermostat to 23C in the hall, and know that then means the bedrooms off it are near 21c. When its a sunny day, the room at the back that gets all the sun over heats, because the hall is in the shade so it is not externally heated. At least with sensor in each room, we have all the rooms perfectly balanced to the same temp.

It looks like the comp curve is set + or - X degrees based on the temp from outside. I dont really want to be messing/adjusting the temp frequently, id rather have it automatic.... which I am guessing that based on the outside temp reading it is automatic, if the curve is set correctly. However, I am not sure what the curve +- is of..... is the room temp? When you say, shouldnt be bounding off the thermostat, do you mean the rooms should not hit the max temp? If so, then in theory they wont (give or take the +-0.5c variance. Or, I can change it back to flow temp? and if so, what temp would you recommend. It just seems wrong that if there is a tiny demand in one room, that the ASHP is running as though it is heating the whole house, when it should just be a small amount.

@JohnMo I did originally have the controller set on flow temp, but the installing company then change it to compensation curve. I am not sure what the best setting is to have - flow, or curve. The Tank temp is set at 50c, and currently shows the tank being at 44.5c. When it was set to Flow temp, it was set at 38c.

The spec supplied said 200mm centres, but I thought the installer had said that the spec from pipe supplier wasnt based on a passivhaus house, with the slab insulation we had so he advised on making it wider. The span in the pic is 3m wide and I think 24 loops.