Hydrostatic Test Stand

I'm contacting you from Naval Base Kitsap, Bangor, in Silverdale, Washington. We have a Hydrostatic Test Stand manufactured by Stellar Industrial, dated 2005, model 1086, Part Number 1086-1, Serial No. 003.

We're having problems with the Regulator and I'm trying to find a manual or way of repair. We are a repair facility for the Navy and do a lot of repairs on equipment we've purchased. If there is any information you can provide, it would be greatly appreciated.