Check valve Secure 4 Model 350
The secure 4 limiting valve use by caravans is no longer available and apparently new van have then pre-fitted.
Please call the number below for advice on these new units or a 'LOGOI Valve 15mm 350kpa plvcv15"
Coast to Coast RV Services
48 - 56 Meakin Road, Meadowbrook QLD 4131
Phone: 07 3805 7117
Fax: 07 3200 5400
Email: salesqld@coastrv.com.au
How this valve worked, was it contained a pressure limiting valve and a non-reversal valve. So to manually replace it you instead need two parts. You could source these parts from your local plumbing store like Reece plumbing.