Raypak Versa Honeywell gas valve replacement

[MelRob]

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

 

[mgarf33]

The gas valve type is matched for the ignition set up. When the mfg calls for a slow open valve, it's best to use a slow open valve to allow time for proper ignition sequence.
If you use something else, you may have intermittent ignition failures, if it ignites at all.

 

[MelRob]

Thanks, mgarf. I ended up using a Honeywell VR8345K4809 which is a universal slow opening valve. Between this and discovering and resoldering some broken solder points on the (original) pc board, the heater is back online, firing every time. I can see the slow opening feature is designed to avoid the BOOM of the old valve opening up immediately, letting the full flow out upon opening. Now the fires with a bit of a delay and with a subdued whomp. Seems to be a good safety feature.