MVHR Dual Speed Fan Control Problem

[Dannyspark]

Hi All,

Any advice on this topic would be very much appreciated as I have hit a brick wall on this.

I am installing a Mechanical Ventilation System into a domestic property, which for those who don't know is basically a whole house ventilation system that takes out stale air and draws in fresh air.

My technical issue is this:

The system under normal operation is set to Low Fan speed, which it stays in permanently giving background ventilation. The client has also specified that he wants an automated boost facility for the bathrooms and kitchen, but doesn't want the nuisance of having to switch something over when he wants to take a shower.

As such I have installed Humidity sensor switches in the hot/wet areas, which when wired back to the Vent system need to kick it into high speed when the ambient humidity rises.

The fan motor is very basic and as such will not accept two seperate 230v signals at the same time i.e 230v to the low speed connection and 230v to the high speed connection without causing some strange annomalies probably as its causing a short I imagine.

What I require is some form of automatic switch device that interrupts the low speed phase connection when it receives power from the humidity sensor switch rediverting it to the high speed fan setting and then in turn switches back after the humidity sensor switch shuts off.

Any thoughts on appropriate equipement to do this as I have drawn a complete blank and this is the first ventilation system I have worked on?

Many thanks in advance chaps.

Danny

 

[telectrix]

can you use relay/s . n/c in low, energised by humidistats to open the low speed supply and close the high speed?

 

[Dannyspark]

can you use relay/s . n/c in low, energised by humidistats to open the low speed supply and close the high speed?

Thanks for the reply. So how would this look in practice and is their a proprietry piece of kit for the job or would it be a component make up job?

I've not had to fashion something like this up before.

 

[telectrix]

think you'll have to build it in an adaptable box. search tinternet for proprietry unit.

 

[hasel5]

what make of mvhr unit you got as the ones we fit have a boost facility via the built in sw line

 

[Dannyspark]

The unit is a DISMY DF35 Complete Eco Retrofit

It has three seperate terminations for low, med, high fan speed.

 

[Dannyspark]

think you'll have to build it in an adaptable box. search tinternet for proprietry unit.

Thanks for the advice telectrix, but I have zero experience of building a relay. Would it be possible for you to outline the process for wiring this and what components are required?

Many thanks again for your help.

Danny

 

[hasel5]

We fitva double pole sw at all rooms that need to run at a higher speed and when the light comes on in this room it send power to a higher fan speed the units we use are nuaire box

 

[Knobhead]

Have a look at X-STK Product Browser you should find a relay to suit. Or search 10A DPDT relay on Google

 

[chesneyhawkes]

You can use the Vent axia ecotronic humidistats, they have changeover relays in them. I can probably get a wiring diagram if you like.