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.