Replacement Thermostat : MainCor to SANGAMO

[Bubblefish777]

Hi
I have a broken MAINCOR thermostat with the following wiring (see picture)
According to the wiring diagram The live seems to be Terminal 1. Neutral is Terminal 2. Terminal 3 is SL. Terminal 1 and Terminal 4 are linked. (See Diagram RED and Picture)

Ok so I wanted to replace this with a SANGAMO CHPRSTATT.
However The wiring diagram from the SANGAMO (in blue) is confusing as the Live (Term2) and Neutral (Term3) seem obvious but is that Maincore Terminal 3 SL connection meant to go into Terminal 1 of the SANGAMO???

Also if this is the case why is the MainCore Term1 and Term4 linked.
Trying to understand this stuff rather than follow it blindly.

Thanks in Advance
Adrian.

 

[RandomGrinch]

is that Maincore Terminal 3 SL connection meant to go into Terminal 1 of the SANGAMO?

Yes

Also if this is the case why is the MainCore Term1 and Term4 linked.

Because it's not linked internally, as it is on the Sangamo.
Without the link, the Maincore allows for 'voltage free' switching, i.e. a boiler could be using 24V switching rather than mains.
Your Sangamo couldn't be used with a boiler that had (extra) low voltage control circuitry.

 

[Bubblefish777]

Thank you so much >>>>