My pool heater is a 27 year old Raypak Versa that I've discovered is not firing up due to the Honeywell gas valve going bad. I was checking the electrical terminals with my volt meter when it would fire up intermittently while applying pressure to the pilot wire terminal. Per Raypay, the replacement valve for the C-405A-EN heater is the Raypak 003900F gas valve kit. This includes Honeywell valve VR8304K4814, a slow opening valve. Further, there is a universal replacement valve available, the VR8345K4809, also slow opening, which is considerably less expensive. My question is: Does the replacement valve have to be a slow opening valve or could it be a regular opening, 2 stage valve such as the VR8345Q4563 or the VR8345M4302, a regular opening, single stage valve? These are even less expensive and readily available. Thanks, Mel