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Strange readings and behaviour


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I'm not sure my MVHR is right. I just been running the fan speed at 100%. When I put my hand over the Exhaust vent outside I feel a good strong air flow. However when I put my hand over the supply vent outside I feel no air going in - putting a tissue is front it appears not to be pulling any air in. However when putting my hand over the supply vents inside the house I feel a good flow.  So this is the first odd thing.

The next thing I notice is the air coming in the supply vents within the house is really quite cold. Looking at the temp information on the MVHR unit I see this:

 

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Now according to this document http://www.cres.gr/greenbuilding/PDF/prend/set4/WI_25_Pre-FV_version_prEN_13779_Ventilation_for_non-resitential_buildings.pdf

 

Exhaust air is the air going to outside whereas the extract air is the air coming from the rooms. It seems to be that the temporatures are back to front? and also given the supply temp is also low.

Shouldn't it be :

 

Exhaust air : 9 oC

Extract air: 15.1 oC

Supply 15 oC back into the house?

 

 

 

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Ok, so just doubled checked everything. The ducts are all connected correctly. I just took the panel off the front of the unit (Nibe) and it seems the extract fan is not running. I've checked the settings and the extract/supply speed are matched so perhaps the fan is broke? I will contact the suppliers.

 

As a side note I've had nothing but issues with the Nibe MVHR and also ASHP. Not recommended at the moment.

 

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3 hours ago, MJNewton said:

If the extract fan isn't running howcome you can feel a strong flow out of the external exhaust vent? 

 

I know right. So strange, I can only presume because only one fan is running its pushing/pulling air differently through the unit. But it makes no sense to me as the air has to be coming from somewhere to push into the house and out of the unit...

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Those figures are complete nonsense or it indicates something seriously wrong with the unit/installation. Extract air temperature should be roughly the temperature of your wet rooms , say 21 to 22 deg. Exhaust air should be lower, and how low depends on the external incoming air or outdoor reading in your display. Supply temperature should be only a degree or two under your room temperature as the heat exchanger does its business to warm up the outside supplied air temp which in turn cools the exhaust temperature. My Brink at 10 deg outside is currently supplying 21.7 fresh air. House is running at 22 generally but 23 in ensuite and kitchen warm after evening cooking. The Brink gives volume flow rates for both fans so I can see what is happening.

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