You can put the pressure sensor anywhere in the cooling system but realize that if mounted in the water pump housing outlet side, you may get pressure affected by rpm.
I think the best place is at the top of your expansion tank, which should be connected to the low pressure or inlet side of the water pump.
Jeff

-----Original Message-----
From: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Monday, November 6, 2023 6:01 AM
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: flyrotary Digest #5352

        Rotary motors in aircraft Digest #5352

 1) Water Pres. Sender Placement
    by "DOUGLAS LOMHEIM dlomheim@aol.com" <flyrotary@lancaironline.net>
 2) Re: Water Pres. Sender Placement
    by "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
 3) Re: Water Pres. Sender Placement
    by "Andrew Martin andrew@martinag.com.au" <flyrotary@lancaironline.net>
 4) Re: Water Pres. Sender Placement
    by "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>

This digest is sent to you because you are subscribed to
  the mailing list <flyrotary@lancaironline.net>.
To unsubscribe, E-mail to: <flyrotary-off@lancaironline.net> To switch to the FEED mode, E-mail to <flyrotary-feed@lancaironline.net>
Send administrative queries to  <flyrotary-request@lancaironline.net>