Keno

Just an update and close to this if anyone else finds they are in the same boat. I purchased an endoscope from AMZN and used it to view the inside of the ducting but I could see no breaks in the ducting. I cut a hole in the plasterboard ceiling and stuck my head up to have a look. About 4 feet from where I cut I could see a "junction box" where the supply spilt off into 4 different ducts. The bottom of this junction box had been dislodged and the air wasnt going anywhere. I had to cut a second hole to access and glue the bottom lid back on. In the picture the 2 pieces of timber are holding the lid up to let the glue dry after repair. I will also use airtight tape as a backup to the ducting glue. This job was a right pain in the ass to locate fix and repair the ceiling. I did it myself but Im sure it would have cost a good bit if I had to call in an expert. The crowd that put in the ducting weren't great and in the end all we had them do was the ducting. I did a diy on the purchase and installation of the actual MVHR and vents, which turned out to be a good decision based on this junction box failing only 2 years of use by shoddy workmanship. Hopefully this can help someone if they run into the same problem.

Due to the breeze I'm feeling, it seems like a disconnection.

Yeah, I was thinking a cheap endoscope on Amazon to try and see the problem. I dont fancy cutting out the plaster board to fix the problem.

ducts are 6" diameter and have been working perfectly for 2 years, this has only happened in the last 2 weeks. I can feel a breeze coming from the drop/false ceiling were the ducting enters, the breeze stops when i turn the machine off, so its a leak somewhere.

Hi All, my supply vents are giving very little air to them. I have an anemometer and have balanced the system myself upon commissioning 2 years ago. I checked all vents and my extract vents are bang on from the flow rates on commissioning, but the supply vents are producing very little. I have taken off the spigots from the MVHR unit and the machine is producing very good supply and extraction. So i know the problem is within the ductwork. I can feel a breeze coming thru the false/drop/void ceiling that my ducting runs thru. Does anyone have experience in the best way to find a disconnection of ducting, without tearing pieces out of the ceiling to find the particular spot?

Only 2 of us, however we can get 2 good full showers out of it and then it only takes 30-45min to come back up to 48c, so if there were 2 more people in the house I dont think it would be an issue unless the 4 people shower at the exact same time every day. Our refrigerant line run is about 3m (10') from compressor to hydrobox.

Thats definitely worth a try, Im going to try it over the weekend. Thanks

200l

Interesting, my cylinder unit is inside and all pipe work lagged. Just curious Stones, do you have a cold water storage tank inside that maybe gaining heat from the house ambient air? My cold water tank is outside and its always very cold coming into the house.

Thats great info , Thanks, very similar to my setup and my ufh cop but your well ahead of my DHW cop.

Thx folks for the replys, so I timed the cycle tonight, it took 40 minutes after a shower was taken, with the outside temp of 2c. The flow temp seems to keep 5C above the temp of the water and the highest it got to was 51C flow the return was about 5c less at all times when it finished at 48C in the cylinder. Thanks j1MBO for the numbers, your COP seems 2x better than mine, although you seem to use twice the kWh that we use. Maybe Im just being picky but my ufh cop seems bang on, DHW Im still not convinced is normal.

8KW

This time of year we use 3-4kWh per day on DHW. I have the setting on economy for dhw so it takes prob 30-60 minutes depending on how much water she is heating and the temp outside. From what I remember I dont think the flow gets that hot when using economy setting, but will know more later when it heats and Ill post.

Yes the cop varies month by month but not by much, around 1.85 in march climbing to 2.1 in july and august. Then slowly back down to 1.75 - 1.85 in winter. Ill post the flow and return in a while when she kicks on. Cylinder is 200l. There is only 2 of us in the house.

On the front of the hydrobox on the ftc5 screen it breaks out consumed and delivered energy in kWh per month or year Thx very much for posting that. BTW Im looking for A2W real world DHW cop, doesnt have to be an Ecodan.

Hi all, we have an Ecodan A2W heatpump (spilt not monobloc) with the pre plumbed cylinder all in one unit. I have the DHW set at 48C. The cold water storage tank is out in the shed, so the water coming into the hot cylinder will be quiet cold in the winter. The immersion is powered off on the unit, so thats not affecting it. I do one manual legionnaires heat to 60c once per month. My average cop for winter ufh is 3.45 with downstairs stats set at 21C, upstairs we dont need the heat. I found the best setting for our need was to set flow temp at 28C. So Im happy with this COP. However we are getting a DHW cop of 1.83 in the winter months with 2.1 in high summer. Does this sound low, its hard to tell without other realworld users thoughts?

The slab cooling is performing really well, house is very cool now, as its 30+ outside with bright sunshine. I have to say Im shocked at how well this works.

Issue resolved! For any Ecodan users, this maybe of help for future diagnosis. It turned out that when the compressor is exposed to direct hot sunshine as we are having now, the thermistor reading would be way off, tripping the PL error, I have simply shaded the compressor from the sun but left ample air flow around the fan/coils. Flow temp is constant 12c and floors are about 17-18c, will see how long the house takes to cool now. Just wondering how other users are finding the slab cooling method in this heat?

I have located the thermistor on the liquid pipe within the hydrobox inside , the pipe is defiantly cold, there is no way that any pipe within the unit is +75c or even close to it. Still confused

Hi all, have an Ecodan 8.5 heat pump with preplumbed hydrobox. SUZ-swm80va and box is EHST20D-VM2D. I have switched the jumper at sw2-4 to on to activate cooling mode. Set flow temp to 12c I now have access to cool the slab via UF pipes, the system works well for 3 minutes or so, the compressor kicks on and the pipes do indeed start to cool, but after about 3 minutes the system throws an error "PL" on unit OC. When I look up the code on mitsu installers website I get "Abnormal pipe temperature is detected in cooling mode." "The liquid pipe thermistor on the indoor unit has detected 75c or more when the system is in cooling mode." "Check the 4 way valve is operating correctly. Run the system in heating and cooling and check the operation of the valve in both modes." Has anyone run into this issue before, it seems like all the threads Ive searched, most Ecodan owners here just flip the jumper at sw2-4 and it works for them. The part I cant get my head around is "the liquid pipe thermistor has detected 75c or more", when both refrigerant pipes coming in and going out of the inside unit feel very much cold.????