Lack of condensate from Zhender MVHR unit

[markharro]

We dont yet have our outlet plumbed in to the drain but rather it is dropping into a bucket below the MVHR unit and empty the bucket as and when needed. Because of this its easy to monitor the water coming out - the confusing thing is that the bucket has been dry for about the last 6 months! Is this normal over the warmer months? thanks

[JohnMo]

Yes pretty normal, we don't make much condensation in summer. It's warm or warm damp air in winter from house being cooled across the heat exchanger, releasing water which goes to drain.

[Jolo]

Same here. Since I installed our current MVHR unit in March or April (can't remember exactly!) it dribbled for a few weeks, then it's been dry ever since. I also have it dropping into a bucket, for the same reason! Must buy that concrete hole drill...

[Nickfromwales]

Defo not an issue.
 

Some AC units and fan coils can be set to not go to a low enough temp to produce condensation, to mitigate needing a waste pipe or pumped solutions.

 

All good   

[FarmerN]

5 hours ago, markharro said:

We dont yet have our outlet plumbed in to the drain but rather it is dropping into a bucket below the MVHR unit 

Do you have a self sealing waste( Dry Trap ) valve fitted, or is it literally straight into a bucket?

If not it may be able to draw air back into its self. Not sure what this would do but probably not ideal.

My Zehnder could draw air in that way, making gurgling noises once there was condensation.

[Conor]

On 22/09/2026 at 13:50, markharro said:

We dont yet have our outlet plumbed in to the drain but rather it is dropping into a bucket below the MVHR unit and empty the bucket as and when needed. Because of this its easy to monitor the water coming out - the confusing thing is that the bucket has been dry for about the last 6 months! Is this normal over the warmer months? thanks

I've had a bucket under our mbhr for four years now. It only produces condensate when it's cold and dry outside. Dry most of the time. Maybe makes 10l in a year.