MVHR Condensate Drain

[richo106]

Hello all

 

I have slightly above zero knowledge on even basic plumbing however I need to pipe up my MVHR condensate drain so it can be boxed in etc.

 

I have a Vent Axia Sentinel and on the instructions it says it accepts a 22mm pipe (see attached)

 

I know I need to install a HepVO trap and the smallest size they do is for 32mm pipe, is it just the case of installing 22mm pipe onto the unit then increasing the pipe size to 32mm for the trap and then carry the pipe on in 32mm into my soil stack?

 

Or would you just use a reducer and expander of 22 to 32 just to install the HepVO trap?

 

Is it best to use solvent weld or is push fit ok?

 

Any advice or best ways to do this would be really helpful as I am not sure which way to go

 

Many Thanks

 

 

 

[richo106]

Or is the norm to connect into the unit in  22mm then step it up to 32mm for the filter and then use 32mm back to my soil stack? 
 

Solvent weld or push fit?

 

Many Thanks 

[andy500]

I used 21.5 push fit overflow pipe - used for boiler condensate etc - straight out of the unit, added four elbows to form a little U bend with maybe a two inch high water seal, and then I dropped the pipework down into a bathroom soil pipe. Little bit of silicone to hold it together and make sure it’s airtight. It’s been running 15 years, no problems. Maybe twice I’ve chucked a bit of bleach in the base of the unit when I’ve had the heat ex out for cleaning, other than that zero maintenance.

I don’t know what a hepvo valve is but I’d guess it does the same job - keeping smells out.

[Blooda]

First thing to make sure on the vent axia is to connect to the right drain on the machine.

 

There are 2x condensate drain positions - one if you are configured with vertical discharge, and one if you are configured with horizontal discharge.  They are both there, so it is easy to pick the wrong one.  The picture your showing is for the vertical discharge.

 

I did as you say and run mine in 22mm until near the vertical waste then went up to 32mm for valve and the last bit to the waste stack.

 

You can buy a Hepvo for £36.88

 

https://www.toolstation.com/osma-hepvo-pp-waste-valve-wt/p87210

 

or alternative for £15.93

 

https://www.toolstation.com/viva-magna-self-sealing-waste-valve/p82878

 

 

[richo106]

21 minutes ago, Blooda said:

First thing to make sure on the vent axia is to connect to the right drain on the machine.

 

There are 2x condensate drain positions - one if you are configured with vertical discharge, and one if you are configured with horizontal discharge.  They are both there, so it is easy to pick the wrong one.  The picture your showing is for the vertical discharge.

 

I did as you say and run mine in 22mm until near the vertical waste then went up to 32mm for valve and the last bit to the waste stack.

 

You can buy a Hepvo for £36.88

 

https://www.toolstation.com/osma-hepvo-pp-waste-valve-wt/p87210

 

or alternative for £15.93

 

https://www.toolstation.com/viva-magna-self-sealing-waste-valve/p82878

 

 

Thank you!

 

Daft question - how do I know what drain discharge I am configured for?

 

My MVHR unit is sat on a board (with anti-vibration feet) so was planning on using the drain hole at the back as pictured. Can this have any horizontal pipe work? I was going to come out the back of the unit, set it down about 6inch and run this 'horizontal' for around 1.5m until an elbow straight down  and then ill step it up to 32mm then HepVO and then into soil pipe.

 

Please see attached dodgy drawing

 

What did you use to step the pipe work up?

 

Many Thanks

[andy500]

Just put a gentle fall on the horizontal pipe same as you would on a waste pipe. It’s only water that flows down it - add gravity and it’ll work fine.

[Blooda]

On 24/07/2023 at 11:22, richo106 said:

Daft question - how do I know what drain discharge I am configured for?

 

Not a daft question at all, the configuration Is not entirely clear, and I think there is bit of translation error.

 

In the darkened loft reading the instructions, I initially took the vertical discharge and horizontal discharge as being the configuration of the extract duct to outside. Vertical is where the extract to outside is where the spigot is from the top [as supplied]  Horizontal is where you moved the extraction spigot to the side.

but that didn't make sense.

 

And tech support were not entirely clear either but did say you only need one.  

 

Configuration:-

 

22mm with a fall to near the Hepvo [copy]

 

One of these:-

 

 

  Then 32mm connected to the Hepvo

 

 

Hepvo

 

32mm pipe to 110m strap boss to downpipe 

 

 

 

A few clips along the way.  And insulated if in a cold loft. 

 

January 22 prices,   That Strap Boss is now £8.88 - 39% Increase 

[Jim K]

Just to add to all this...

 

In my bungalow I don't have a decent route in the loft to get to a drain or an outside gutter, so I've bought a Grundfos condensate pump for £80.

 

Although this sounds like overkill, it will allow me to run the tube to a soil stack 12m away over an obstacle course, or go out the wall to the downpipe of a gutter. No dry traps, hardly any pvc pipes or insulation. It also allows the overfill interlock relay on the pump to stop the MVHR unit automatically if there's an issue.

 

It'd be good to not need a pump but in my case there's no avoiding it. It'll only be used for a few months of the year and should stay unfrozen under the loft insulation.

Edited August 5, 2023 by Jim K