Biasi M90e 28s external thermostat wiring

[the_jinj]

Hi

I recently got a Hortsmann HRFS1 thermostat to control my Biasi boiler.
The Hortsmann is setup ok and appears to be switching on and off as desired. 2 core running to boiler from OM and NO contacts of the thermostat to the boiler.
According to the manual you connect to connector 1 and 3 (with link removed). I notice that there is a link from the supply neutral to connector 1 on the no voltage connector - is this correct or has it been added at some point? Connector 2 is grey, 3 red.

I've attached a pic of the boiler side wiring. The service manual doesn't show the connections from the connector to pcb so not sure.

Untitled

• the_jinj
• 13 Mar 2014
• 1

Any help appreciated.

Cheers

 

[D_Hailsham]

The red, grey and blue wires are the boiler side of the connector. Your stat will connect to 1 and 3 on the other side of the connector.

The stat is just a temperature controlled switch. If there was no wire connected to 3 on the boiler side, the boiler would never light.

 

[the_jinj]

The red, grey and blue wires are the boiler side of the connector. Your stat will connect to 1 and 3 on the other side of the connector.

The stat is just a temperature controlled switch. If there was no wire connected to 3 on the boiler side, the boiler would never light.

I had to set the internal timer to override. Was thinking about the voltless contacts in the wrong way, silly me. Now sorted