PIV is a flat advice please

markin

Having the heaters on aren't worth the cost at 400w 24/7, a piv is worth a try before spending 3k on a small mhrv.

Are you sure it's not a drain issue? Water getting sucked out the traps as the not a vent?

Edit. Read the past threads, did you install a bathroom extractor?  Are you now heating 24/7 to 16c? Are you running the dehumidifier 24/7 ?

And probably best to stop drying cloths in the flat altogether.

agylk

All other causes have been addressed and problem unsolved 

markin

Maybe it would be more worth while to install an Air-con unit that's an air to air heat pump, it would move the air around and dry it at the same time, and not bring in any damp outside air.

How many liters a day are you getting in the dehumidifier? Is it still 70% humidity?

greyteam1959

agylk said:

Thank you. I wrote previously a long post about it but no one noticed it. In any event, after many years doing everything in my power to reduce humidity problems and smells in this flat, I am at a complete loss. No one has ever found any mould and I’ve had six specialist here including a surveyor. I’m at a loss so the only thing remaining is to install PIV. I also live very close to the sea. 
Nuaire told me it cannot be turned off and if I was to turn it off, it would be bad for the unit. I don’t know why. 

I think heat recovery units are expensive to run as well… 

I would agree with Nuaire about not turning the unit off.
I put a Nuaire unit of mine on a timer a few years ago in a cost saving effort.
The unit failed after a couple of months.
Could have been a coincidence.