MVHR - Frankische E11 Supply air error

[Street18]

Hello, I hope someone can help. We installed a Frankische profi-air 250 Flex in the loft in our new build. The ducting to and from the rooms in insulated on the loft floor and in the stud walls / ceilings. As you can see, the ducting for the fresh air and extraction on top of the unit are the normal type ducting that go out via the roof. During the winter when the outside air temperature is around zero, the loft drops to about 5 or 6 degrees C. At which point the unit switches off as such and the app displays the below error - E11 Supply air temperature <+5C. I'm assuming the error and shut down is due to the unit not liking the cold air as some form of protection.

- Has anyone got any experience with this error with a Frankische unit before or similar with another branded unit?

- Do you recommend I insulate the fresh air and extraction ducts? If so, with what type of insulation?

- Should I insulate the unit itself? Is that the actual problem?

I appreciate any help, as currently through the winter, as it's been cold, the unit is off more than it is on, so not ideal.

Thank you in advance.

 

[Nickfromwales]

If I saw air temp that low coming into the house I’d want it heated somehow. 
 

I doubt adding any more insulation will help here as the fan is sucking cold air in and that’s being detected by the sensor inside the unit.

 

Consider an inline heater to bolster through the worst of the winter, as the heat recovery doesn’t seem very good either that unit? Maybe for a much better long-term solution you could consider a far better unit.  

 

LINK

[Mr Punter]

All the pipework to and from the plenum boxes, as well as the boxes themselves, should be insulated. 

[Nickfromwales]

Just now, Mr Punter said:

All the pipework to and from the plenum boxes, as well as the boxes themselves, should be insulated. 

+1

[JohnMo]

ALL your pipes/plenum should be insulated in the loft - can see plenty in your photos not insulated.

 

It appears to shutting down to protect the heat exchanger, but seems to be doing very early. I would have a read through the manual for the unit. Mine will go into extract only mode if it needs to protect itself, but it never seems to need to.

 

A pre heater as linked to above is the normal way to do it. It can be electric or water based.

[Bramco]

Is it to do with the fact that the temperature of the house air being extracted is 10C - that's pretty cold - my SWMBO would be complaining at that.  I wonder if the unit complains because there's no heat in the outgoing air to put back into the incoming air?    I'm assuming that the supply air has been a lot lower than 5C for some time as it's showing as 1C from the display.

[Tom Heywood]

If the unit has frost protection, make sure the temperature it kicks in at is aroubd zero degrees. If you don't have a frost protection built i, add one to the intake duct. 

Also INSULATE those ducts and manifold otherwise you will get some big issues with condensation

[Street18]

Thank you all for your responses. It is appreciated. I will get the ducting insulated. Regarding the in type of insulation, please can you advise of what you recommend for the ducting we have? The larger incoming and outgoing air ducts you can see at 190mm diameter and the smaller ducting supplying and extracting from the rooms is 90mm diameter. I'm a total novice, so any links would be appreciated too.