Heat Recovery System

[DanDare1]

Help please!

I would like to run my transformer-powered Heat Recovery System so that it turns on to full power when I turn on the light switch (via the relay indicated); but it also turns on to trickle when either the PIR or humidistat are activated. The transformer has several voltage settings to control the running rate as can be seen from the diagram.

Please could someone have a look at the diagram in my album and see if the proposal works? My electrician has already melted one transformer and I would like to make sure we have the right wiring diagram before having another go. He is concerned about the two power supplies to the HRS being turned on at the same time with consequences...

 

[bernardgreen]

The circuit as drawn will put a short across transformer's 160 volt and 80 volt taps. Thats 80 volts into a dead short so it is not surprising the transformer burns out.

Use the normally closed contact of the relay operated by the lamp to enable the PIR and humidstat.

Remove the connection from PIR teminal to the L on the HRS. Then instead connect the PIR terminal 3 to the Normally closed terminal of the relay.

Beware that if the PIR is active when the lamp is turned on or off there may be a fleeting arc as the relay's common moves from 160 to 80 volts or vice versa. You will need a relay with at least a 3 mm gap between contacts when open otherwised relay life may be short before contacts are worn.

 

[DanDare1]

Thanks very much for the prompt response. I will pass it on and hope that we have no more mishaps....

Kind regards

DD