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I have a 14kW Mitsubishi Ecodan, which heats 2 zones (zone 1 = house with rads and zone 2 = kitchen with UFH) and DHW. I spent a good time playing with weather compensation only to find that room temperature with auto adaptation heats better with a higher COP - happy bunny! However, there does seem to be a slight issue. Auto adaptation seems to set itself to the lowest flow temperature to match heat input to heat output. So zone 1 heats well and is very efficient. But the system doesn't run zone 1 and zone 2 at the same time - zone 1 takes precedent if it calls for heat. So zone 1 seems to be on all the time (nice and snug!) and zone 2 seems to be off most/all of the time (a bit chilly). Does anyone have any suggestions as to how I might be able to get some heat to zone 2, while still being able to benefit from auto adaptation? Thanks in advance for any help or advice you can give.

Hi everyone, Two years ago, I purchased a 14kW Ecodan air-to-water heat pump with R32 refrigerant. Recently, I decided to install a Wi-Fi remote to monitor the temperature in my living room and control the heating more efficiently. However, after enabling the remote, I encountered an issue where the system displays an L9 error after a few hours, and the heat pump shuts down. Based on my research, this error seems to indicate a flow issue. I have already taken the following steps to resolve it: Cleaned the water filter: I ensured there was no debris or blockages in the system. Checked the water pressure: It is approximately 1.6 bars when the system is off, which seems to be within the acceptable range. Increased the pump speed: I set the pump speed to level 5 to rule out insufficient flow as the cause. Unfortunately, none of these actions resolved the issue. During my observations, I noticed something unusual: the circulatory pump does not start even when the room temperature is below the set temperature. The pump only starts if I manually trigger it through the heat pump settings. Once it starts, it operates normally, which suggests the pump itself is not faulty. Additionally, I activated the feature to display the ambient temperature reading, and the values seem accurate. This makes it even more puzzling why the circulatory pump fails to start automatically. At this point, I am left without heating and am unsure how to proceed. Does anyone have any insights into the cause of the L9 error or potential solutions to this issue? Thank you in advance for your help!

We have a new 11.2 kW Ecodan ASHP and all UFH in concrete floors in a large well insulated house. I started with Weather Compensation and was satisfied, with little cycling, but decided to try Advanced Auto Adaptation extending the cable from the little FTC box, moving it into the living room. It is working great, using low power and no cycling. The only con is that as there is no connection from the existing house thermostats to the FTC, I have to keep the living room thermostat set the same as the FTC thermostat so they switch off at the same time when the room temperature target is reached, otherwise the UFH pump will run unnecessarily, although it doesn't use a lot of power. I now intend to order a Mitsubishi wireless controller and receiver (£167). Any comments?

Hi all, We are having some problems with a new Ecodan install and with the heating now on it's clear that it's not performing as expected. I want to check I'm on the right tracks before going to the installer and getting another TADTS type response. 8.5kw Ecodan serving two UFH manifolds: GF - set in flow screed approx 70sqm, 4 zones FF - grooved overlay panels (12mm pipe), 70sqm, 3 zones. When there is a call for heat everything fires up as expected. However if only a couple of zones are calling for heat it will run for just a few minutes before switching off. Not just the compressor cycling on/off but also the heating pump (I would have thought with short cycling that the pump would continue to run and just cycle the compressor on/off depending on return temps?). It then sits dormant for a good 15 minutes before repeating. It often won't run long enough for the UFH return loop to even become warm. I can see from the thermistor readings that the return temp matches the flow within a few minutes. I expect the problem is exacerbated by the small-ish 12mm pipes on the first floor as the flow through these must be tiny compared to the flow from the heat pump. I think we might have a minimum volume problem and/or a flow rate problem. Can anyone confirm if that sounds right and what the correct solution would be? Many thanks, Olly

A couple of years ago, I bought a house heated by a 14kw Ecodan ASHP with a Mitsubishi pre-plumbed cylinder system, that was installed in 2015. It has zone 1 to heat 10 radiators and zone 2 to heat 3 loop wet UFH for the kitchen and utility - also heats DHW. During the colder winter months and late frosts this year, it was clear that the UFH was failing to heat the kitchen/utility floor. The input to zone 1 is physically higher on the low loss header, so if both zone 1 and zone 2 are on at the same time, zone 1 takes the heat, and no heat travels down the low loss header to zone 2. If just zone 2 is on, some heat goes into the zone 2, but much of it travels down the low loss header to the return. This causes the return to be almost as hot as the flow, so the Melcloud reports show the return temperature tracking the flow temperature. When it reaches the peak temperature, it cuts out and flushes with cold water from zone 1. This shows as a sawtooth effect of fast cycling - the cycling is very regular, every 10 minutes. If zone 1 is on by itself, this does not happen - the return remains lower than the flow and there is no cycling (I've attached a melcloud report showing this). The system has been serviced, I've flushed the UFH loops out (via hose - a small amount of muck came out but not much and the flow was OK) and inserted more biocide. I've tried altering the pump speeds. To reduce any flow obstructions, I've removed the flow meters and used blanking plates. I've replaced the Heatmiser UH2 with a standard Ecodan wireless thermostat, and Salus THB23030 actuators. I still have the 10 minute cycling. I have a feeling that the ASHP is too big for the UFH by itself - but not big enough to heat both zone 1 and zone 2 together. I've tried asking UFH and ASHP installers and maintainers, but they look even more baffled than I do and offer no help (with all the green deal stuff, they are too busy installing new systems to bother with maintaining existing ones). I just wondered if anyone had any thoughts or ideas as to anything I could try? Many thanks Eric

Hi community, Over the last 2 weeks I've been trying to take in lots of info regarding ashp since having one installed in a new build, thanks so much to all the people that contribute with their esteemed knowledge, much of it on here is well above my basic understanding and it seems there are a myriad of things to consider when trying to optimise the systems. Bit of background, 186m2 timber frame kit from a company called scotframe, as a non builder this seemed like a means of eradicating some of the problems with builders as it progressed. Product has been good aside the nordan windows and doors imo, the erectors not so good, wish I'd hired a chippy with lots of new build experience to keep and eye on them but I am where I am now.. if anyone has questions about scotframe always happy to share my thoughts and experiences. Installed I have an ecodan 8.5kw system with ufh downstairs dfor heating and DHW. no buffer tank just the ecodan cylinder with 6 room stats downstairs. Vent axia sentinel mvhr yet to be commissioned / balanced. 75mm screed on top of 140mm celotex. pipe spacings at 125mm (mostly anyway). Been running now for 2 weeks, the house is at a comfortable temp downstairs, 17 deg, and that what's the stats are set at, not lived in yet but in this cold weather seems heating will be needed upstairs with points for electric heaters of some sort ready for the future. After lots of reading on here I've decide to run the ufh at a low flow temp, presently 29 degrees and run it continuously aside from peak pricing times with octopus agile.. . The house seems to hold heat reasonably well but until I move in to a semi building site in around 6 weeks I wont know exactly how it performs. Whilst the heat pump installer / plumber was a lovely chap and had a love for making perfect copper piping I'm not entirely sure how technical he is when it comes to these systems. I have lots of questions but the thing that's initially baffling me is on the control panel for the heat pump when the ufh is running its shows the flow and return temps are very similar circa only 1 or 2 degree loss between the two. From reading on here that seems far too narrow so the lovely heat the pump is generating heat but returning the majority of it . If someone could help me understand the impact this will be having on the heat pump / efficiency and then how I would go about increasing this difference that would be appreciated. The installer left all flow rates at 2.5 which was nothing like the ufh design I've referred back to, so a few days back I reduced these to what the design recommended, but this hasnt affected these flow and return temps which I assumed it would have. As said for many on here with knowledge in this area it may well be like pulling teeth trying to get me to understand what's going on but I'm game for the challenge Thanks.

I currently have an outdated oil fired heating system and I need to replace the boiler, oil tank and pipework etc. I have been in touch with a Air source heat pump provider who quotes a flat £14995.00 install for and ecodan 8kw heat pump, 170 litre hot water tank, 10+ rads etc. Having had a survey done I am due to meet with a sales manager to finalise details. In regards to RHI I have been advised I would receive just under £11K from RHI over 7 years. I have a detached 5 bed house and wondered if this is setup would be suitable and if £15K is about right Any advice would be appreciated, thanks