athlonoc

Update: The response from Heatmiser is one of RF signal issues. They has suggested that if the batteries went low in one or more neostats, then it might be it activated the failsafe on the stat. They state that every hour it will run for 12 mins to push warm water around the system if it doesn't receive 2 RF signals after two attempts. It all makes sense, but of course what they couldn't confirm is where the warm water is coming from. Would it be possible that warmth ( the radiators were not very warm or hot, just warm ) came from heat in the pipes and or the header tank? Any thoughts, just for an understanding. So far 3 full days without the problem. Heatmiser also suggested that by turning off failsafe which is what I have done to alleviate the issue, might want to strengthen the RF signal with a boost box or boost plug.

Oh, ok. So if the switch is on as in the 2nd photo, but the ASHP hasn't fired up as in the 3rd photo, but the pump is pumping warm water around, how can that be? Time for a heating engineer to problem solve. I've spend a fortune on this 2 year old system in my new build as it's been nothing but problematic. I've had 2 separate heating engineers round for example to solve the system pressure as it needed topping up every 3 or 4 weeks, which went on for a year or more. No one spotted the leak at one of the pumps and a leak outside by the filter drain. The company that installed went bust. My faith comes from looking at these problems myself and using these amazing forums. So if I can I'd like to understand and solve myself. Is it therefore possible that the switch is faulty and something other than the stat is turning it on to warm the radiators? If so why doesn't the ASHP come on?

All these stats were installed in this new build and I had no input. 5 stats for 5 zones for the UFH and 1 stat for the rads upstairs. Yes there is a 51l buffer in the loft along with the Ecodan controller box and the HW cylinder. I'm not sure but would suggest it's downstream of the 3 port diverter. I'll go and check and thank you for this. If the diverter port is leaking, would I usually see the switch for the upstairs Central Heating light up? Is it not just the stat upstairs that controls all the rads that would switch that on, even though the stat was calling for heat?

Hi again, Update with a problem. So I didn't bother with UH8 after all. I powered down everything connected to the central heating system. Ecodan unit, UH8, stats, Heatmiser Neohub. Then after a few hours I powered up and repaired everything and it seemed to go ok. All stats paired fine with Switch and the UH8. The Neohub connected to all stats and could control the rise and fall in heat. The HW came on and off in accordance with its schedule. Now after about 6 days of seemingly all being good, I noticed the radiators on the first floor were warm. The noise associated with pumping the flow around the system was running. However, the stats were not calling for heat and the control panel didn't have the compressor symbol lit and after checking the ASHP unit, it wasn't running. So it appears the system was pushing warm water to the radiators ( not the UFH downstairs ), despite it not being heated by the ASHP. So how could this happen? Is the HW tank sending warm water to the upstairs rads? I noticed the the Heatmiser switch, was lit up ( boiler and CH1 ) - but not HW light. I've reached the end of my ability to solve and wondered what my be at fault / causing the system to pump warm water from somewhere to the rads without ASHP running and no stats requesting heat? Thanks Lee

Thanks Mike, I'm going to assume that no interference from neighbours as I live in a well spaced out area with 8 other houses and all have the same setup. No one else is having this issue and mine has been fine up to this recent point where I had a batter icon on two stats and then noticed things with the system were running when not called for. I think might order a new UH8 centre and then see if the problem still exists. As with so much it will be a process of elimination.

Hi, I’m looking for some help / advice to see if there is anything further, I can do. My property is a newbuild of 2 years and was fitted with the following UH8-RF V2 wiring centre 5 NeoAir v3 stats Connected to Mitsubishi ASHP heating system. All has been fine until the last few days where I noticed I could hear the system was pumping water around and at times, I could see the ASHP was running. At the same time I noticed the Wiring Centre UH8 was lit up on a specific zone. When I checked the stats I noticed two of them had battery warning icons up. So, I simply replaced the batteries expecting this to solve the problem. However, things started to go downhill from here. It became obvious that the pairing was no longer right as I was not able to call for heat with all the stats ( testing purposes ). All stats would have a flame but not all the lights on the UH8 would lights up. So, I reset all five zones after powering down the UH8. I was able to pair successfully 4 of the 5 zones but one wouldn’t pair. So, I used a spare stat to see if that could pair, which eventually it did after several attempts, but then I noticed one or two of the other zones would no longer call for heat. I then used one of the three spare zones on the UH8 in case zone 5 had developed a fault. I’m now experiencing intermittent control, when calling for heat. I can manually push any of the zone buttons on the UH8 and they light up. I have now on three occasions, powered down the UH8, reset the master RF button so it flashes quickly. Then reset all 8 zones so they all flash quickly, then one by one repaired with my 5 Neoair stats. In the past when setting up it worked fine and always paired within 5 to 10 seconds, and all would call for heat. I have replaced all batteries in the stats. I have reset all the stats. I have reset the zones on the UH8 But I am left with some of the zones not lighting up when the stat is calling for heat. My questions are: Is there anything further I could try? Is it possible that the RF communication device on the UH8 is now faulty, or the UH8 wiring centre in total. No other RF or Wifi devices have recently been installed that might interfere. Certainly not for over a year and everything was working fine until the battery symbol on a couple of the stats were showing and the flow pump in the loft could be heard running. I’d be very grateful for some expert advice.

I'm not aware that the FTC6 shows pressure but I could be wrong. Skipping through the menu I never came across it. My system is in the loft and I left the engineer to it. So I couldn't comment but I'd like to think he did it this way.

Well, the engineer did say the pressure in the expansion vessel was low and has re-pressurised it. So I will find out tomorrow morning. On that point, has anyone used a Bluetooth pressure sensor over the valve, so you can check instantly on an app and even get alerted when it drops below a certain level. As the valves are the same as those on cars, would a permanent pressure reading cap work?

Well, in terms of a programmer, I have set just the hot water on a timer. Twice a day, 3pm and 3am. The 3am kicks in when we are in a deep sleep and this doesn't wake us up. It's no problem changing just the stats. It does the same thing. Its controllable via the Heatmiser App so all 6 stats can be changed in a matter of seconds. The FTC6 controller is where I have programmed the HW and know I could program the CH that way too. My big issue was not being able to leave it on, while using weather compensation and forgetting it. The noise just prevents this from happening. We still get a COP of over 3 which I'm more than happy with. I have topped it up many times using the fill loop. However, its only recently that I have noticed this first thing in the morning. Since it gets up to pressure within 15 to 20 minutes I now leave it alone and no longer repressure it. I'm convinced none of this should be happening. Maybe once a year check the pressure and fill as required but not every day in the morning. Any explanation why its zero when its not been on for a few hours and then pressurises itself when the system is up and running? Also is it being suggested I keep topping up every morning to 1 bar until the day comes when the system doesn't need doing in the morning. If I keep topping it up, does this cause any issues if it gets to pressure when the system is running? There doesn't appear to be any air in the system. The two bleed valves in my original picture at the manifolds have no air. The valves in the loft of which there are about 9 dont let any air out.

As a side issue which wasn't dealt with by the service engineer due to time restrictions. Due to water flow noise in our system we have decided to turn off our heating when we go to bed at night as the noise stops us sleeping. Its been two years of poor sleep. We just turn the stats down a few degrees to ensure it doesn't call for heat. This is not the way in which we should or want to run our ASHP fuelled central heating. What I do notice other than it takes much longer to get the house to temperature 😠, is the pressure gauge every morning reads zero. Then after 20 minutes or so after the house calls for and starts flowing heat around the pipes the pressure goes up to the set bar of between 1 and 1.5bar. Is it normal for a pressured system like this to drop to zero overnight, then go up when the system kicks in?

There is a circulating pump in the loft. The rooms get warm enough, so technically I guess it's working correctly. Is there any value in just removing the actuators so the heat flow continues and then I would see if the colder elements of the pipe work do in fact warm up? I bought a thermal camera to highlight to my builder there were some issues and by chance I noticed the larger heating runs had cold areas, where I guess I was to assume the pipework would all heat up.

All 5 zones are now calling for heat and on

I have just had my Heating System serviced and asked the question about flow through my UFH I have attached two images showing the flow is not making it around the complete circuit and I have no idea why. Its a two year old system, run by a Mitsubushi Ecodan 8.5kW ASHP. I have 5 zones downstairs ( Hall, WC, Utility, Lounge, Kitchen ) and both the kitchen and lounge have what looks like two separate pipe feeds. My thermal image for the lounge shows even after the heat is pumped into the pipes for over 6 hours it still doesn't manage to flow all the way. The two blue coloured pipes in my thermal images as expected are cold but the two behind it for the lounge are warm. The heating engineer said I should try and run it with the actuators off. I'm advised that this will render the wall thermostats non operational and the flow will just continue. He also states that this will highlight if the actuator is working. Does this sound right? I also have a dense green solution dripping from both the large valves on the left in the non thermal images. It's not a constant drip, but I wiped the floor about 3 months ago and the leakage is there again. Before I fork out to get them back on a fault finding mission does anyone have any thoughts on what might be happening?

I know this is an old thread, but after looking at temperature discrepancy issues between my old slimline v2 stats and my new replacement NeoAir V3 stats, they look very much like those as above which Ultima357 suggested Heatmiser should use. It's now 2024 but maybe he had something...... I hope they thanked you Ultima357 as it appears they listened to you?

Can anyone see how to select or more tot the point know which channel my UH8-RF V2 is using? Also what are the zone switches for? I can see they are all set to 3. The others which I don't use are set to 1

Thanks for your reply. Picture attached.

I am replacing Slimline stats for NeoAir for app control. I have the UH8-RF V2 for controlling the UFH in 5 zones. Installations states you must find the Channel by looking for the two dials by which the Channel is set. I'm unable to see these anywhere inside the UH8. So taking a guess at it being one of the 99 channels, the manual states you should select the same Channel in the stat. Power - then Setup - then arrow down to P2 ( UFH control ) I can't get it to pair at all and as of yet not tried all the 99 channels. Is there a way to know what channel the UH8-RF V2 is set at where there are no black dials? Thank you Lee

Does anyone know if the Slimline V2 thermostats are capable of being seen by Home Assistant to monitor room temperatures. Not sure if I need to upgrade to the Neo stats or not?

Hi Beelbeebub, Well spotted and thank you. I have now informed them that what they left me with and to be honest it's a schoolboy error on their behalf.

I hope these are the three you mentioned. FTC - Main Control Panel - Isolator switch for ASHP? Thanks - report back once done

Also forgot to mention that when it started doing this again 2 days ago, the radiators were luke warm. I only noticed this as I got my towel from the towel radiator and noticed it then! Does this point to something. My controller also constantly shows the play symbol on the hot water, which indicates it permanently trying to heat the water to 48. It's as though it hasn't finished it's attempt to heat to 48. Is there a way to stop it from doing this?

The Bin Man-Thanks for the reply, yes it's had its annual maintenance and last one was 6 months ago. I'll call them today if this doesn't get resolved. PhilT- Can you confirm how to power down. I've seen this video and followed it a couple of times before. The soft reset is done but that isn't having the desired effect. akjos- No I didn't but will do that now and then see what happens Thank you all Lee

Hi all, I have had a dozen L9 errors since my install about 18 months ago. In that time I have a one full service. The L9 error I'm well aware of it being a flow rate issue. Around June of this year I had a random L9 error and just reset the controller and all was well again. July this year it happened again twice so I called out the installers ( they have gone bust but running under a different name ) On that point the guys who worked for this company are still local and were laid off with a days notice but one of them is a mitsibushi tech guy. I have no doubt the installation was carried out fine. My neighbour has the mirror of my new build and he has the identical system to me and installed by the same installers. The now defunct company sent out a nice chap who wasn't proficient in Mitsibushi heat pumps. He checked the filters but was unsure how to resolve and left with an open ticket to do some research. This isn't what I need and will endeavour to push for a mitsibushi heat pump professional. In the mean time I was not able to call for heat after he left and no hot water went to the tank. Every 10 mins or so the L9 error happened. Then I noticed the pressure in the system was around zero ( this I guess is because the engineer they sent over flushed or check the two filters which I guess would have dropped the pressure and he didn't re-pressurise )!! Anyway I've re-pressurised it to 1.6 bar as per mitsibushi's guidance and still it L9 error's Now to the bit that has confused me and why I'm here. I have changed the source of power to immersion in the service setting by altering the setting on the controller from 'standard' to 'heater' This engaged the system and does actually heat up the tank. So all I can say is that there is a lot of stuff up in the loft. I've bypassed the ASHP heating the water up but something up in my loft where all the gear is, is not working correctly. Any thoughts before I call out someone detached from the company who is honouring the warranty install but has since gone bust!!

Just a secondary question with the MEL Cloud App. Both zones (zone 1 and 2) appear to be on indicated by a sun symbol. But all of zone 2 (downstairs UFH) is at room temp so shouldn't be onand isn't according to the FTC6 controller but is according to the Mel Cloud App. Zone 1 is the upstairs rads and it's this stat that is set to heat upstairs at a higher temp but is cutting out on this occasion. The app shows two room temps at 22.5 and the set temp at 20. Can you confirm if they should or can override the rooms stats around the house? Reason I ask this is when looking at the summery settings on the FTC6 , page 2 of that menu has two temperature settings - HRoom1 & HRoom2 These temp settings change when the settings on the app are changed for each zone. So are these independent temp settings from the actual room stats?

It has been used before and appeared to work ok during last winter although it was only installed from December 22 So this is it's second winter.