Teething issues with MVHR

[JohnMo]

22 minutes ago, Tom said:

100mm off the floor and I have a ~50mm high piece of trunking for the hose/pipe to go over

How does water drain if it has to go upwards? Sorry that is not a fix, and will not work.

 

Head scratching time - plan your route that only falls away from unit - only you are there, so only you can do that bit

[Tom]

2 minutes ago, JohnMo said:

How does water drain if it has to go upwards? Sorry that is not a fix, and will not work.

 

Head scratching time - plan your route that only falls away from unit - only you are there, so only you can do that bit

The pipe along the floor would form the U bit of the U bend, as long as the downstream end of the U is lower than the upstream end, then water will flow through it, like any U bend I guess. I can drill through the floor closer to the unit and drop the pipe through though, which seems less of a bodge.

[MikeGrahamT21]

2 hours ago, Tom said:

They said it was up to my plumber (ie me) to connect up the condensate drain. The problem is they are a commercial ventilation installers rather than domestic, if that makes a difference, so perhaps they see their remit slightly differently

Indeed, but the other stuff is definitely them.

 

For now make sure the drain has got a reasonable bend in it to create a good pool of water for the water trap, the more in there the less likely it is to suck air back up.

[Tom]

33 minutes ago, MikeGrahamT21 said:

For now make sure the drain has got a reasonable bend in it to create a good pool of water for the water trap, the more in there the less likely it is to suck air back up.

1 hour ago, JohnMo said:

You need a proper dry trap, like Hep2O ones, close to the unit.

 

What sort of trap do I need? If the drain hose is sucking in air then would it allow a dry trap to open?

[JohnMo]

3 minutes ago, Tom said:

What sort of trap do I need? If the drain hose is sucking in air then would it allow a dry trap to open?

No that isn't how they work. They exactly the same as a normal trap, but with a membrane, that only allows one direction flow.

 

First item that came up 

https://www.toolstation.com/viva-magna-self-sealing-waste-valve/p16545?store=LJ&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&gad_source=1&gclid=CjwKCAiApY-7BhBjEiwAQMrrEV8HMBkKJNR2kKR371ncf4vxKMtfeMcDxK9vPqoY9c1Wyv_FiS0yzxoCbYEQAvD_BwE

[Conor]

Once you have a trap full of water, it's weight will be greater than the negative pressure from the unit. Was there not one supplied with the unit? It can even be a loop of pipe to form a trap. I've still not got mine plumbed in and it's just flowing in to a tub. Only need to empty it every couple of weeks or so.

 

Is this a newly completed build, then your house will be soaking and the unit will want to be boosting. Override the humidity settings and set the fan to something like 33%

[JamesP]

McAlpine Tundish.

Edited 15 hours ago by JamesP
Name

[MikeGrahamT21]

50 minutes ago, JamesP said:

McAlpine Tundish.

Don’t tundishes have holes in them? Not suitable for MVHR drain if it has

[Thorfun]

2 hours ago, JohnMo said:

No that isn't how they work. They exactly the same as a normal trap, but with a membrane, that only allows one direction flow.

 

First item that came up 

https://www.toolstation.com/viva-magna-self-sealing-waste-valve/p16545?store=LJ&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&gad_source=1&gclid=CjwKCAiApY-7BhBjEiwAQMrrEV8HMBkKJNR2kKR371ncf4vxKMtfeMcDxK9vPqoY9c1Wyv_FiS0yzxoCbYEQAvD_BwE

i've used traps like these (but different make) in a few places (under the bath and sinks in the bathroom) and like them a lot.

Edited 14 hours ago by Thorfun
clarified that not this exact make of trap i used

[dpmiller]

best to ensure a vertical drop before these dry traps I find, there can be a bit of water builds up before there's enough weight to "open" the membrane

[JamesP]

1 hour ago, MikeGrahamT21 said:

Don’t tundishes have holes in them? Not suitable for MVHR drain if it has

 

MCALPINE TUNDISH 19/23MM X 19/23MM (5684V)

 (9)

Write a reviewAsk a Question

Clear non-return valve manufactured in polypropylene with 19 / 23mm universal compression connections. Prevents backflow in overflow pipes. Valve opens with the weight of the liquid, allowing it to flow through and then closes once the liquid has passed.

• Mechanical Non-Return Valve
• For Use in Vertical Position

 

Edited 13 hours ago by JamesP
Detail

[MikeGrahamT21]

30 minutes ago, JamesP said:

 

 

MCALPINE TUNDISH 19/23MM X 19/23MM (5684V)

 

 (9)

Write a reviewAsk a Question

Clear non-return valve manufactured in polypropylene with 19 / 23mm universal compression connections. Prevents backflow in overflow pipes. Valve opens with the weight of the liquid, allowing it to flow through and then closes once the liquid has passed.

• Mechanical Non-Return Valve
• For Use in Vertical Position

 

ahh, smart, not seen one of those ones

[Tom]

Well that was a fun evening, managed to get the c9ndensate all hooked up with 22mm pipe, dropping through the floor and connecting to a McAlpine trap:

[Tom]

[Tom]

Many, many thanks for all the helpful advice. I've turned the humidity limit up to 85% and the the thing's as quiet as a mouse. I might have to go and check it's still on...

[Tom]

Oh, and the installer said it wasn't their job to insulate the external feed duct, ffs. It's only a short run, guess I just need to wrap in rockwool?

[MikeGrahamT21]

3 minutes ago, Tom said:

Oh, and the installer said it wasn't their job to insulate the external feed duct, ffs. It's only a short run, guess I just need to wrap in rockwool?

The foiled rockwool, to prevent condensation on the pipe forming, and foil tape on any joints.

 

Glad the unit is behaving now your connected the drain