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Installation
XX163-17-00 Rev 1208 SVFT-PRS Pressurized Dome Housing
Pressurizing the Housing Assembly
24. Reattach the previously removed service cover to the service opening using the four (4) captive screws.
25. Using a regulated source of dry Nitrogen gas with the proper Schraeder type fill fitting, as shown in Figure
9, regulate the gas pressure to 10.0 psi (0.68 atm or bars).
26. Attach the fill fitting to the housing assembly’s fill valve located at the lower side of the housing and
pressurize the housing assembly. When the relief valve opens (gas will hiss from the top of the relief
valve), allow this to purge for a minimum of 5 minutes to assure that all the enclosed air is replaced by
nitrogen; then remove the fill fitting. The relief valve is rated at 5 psi +/- 0.5 psi (0.34 atm or bars +/- 0.03
atm or bars). Monitor the actual pressure for the next hour. If, in one hour the pressure has not dropped
below 4.5 psi (0.31 atm or bars), it is assumed that the housing assembly is sealed and the relief valve is
seating properly.
27. Reinstall the cap on the fill valve.
Caution: Pressurizing the housing assembly beyond 10 psi, or with an unregulated gas source, can cause
severe injury to personnel and permanent damage to the assembly.
Warning: If the dome has been dropped and is cracked, do not pressurize. Replace it with a new dome.
Note: Leakage rate is less than 2 psi per year.
Note: The housing with mechanism has approximately 490 in.
3
of volume.
Note: The pressurized function has not been evaluated by UL.
Warning: Do not use any gas type other than dry Nitrogen. The use of Shop Air can introduce moisture
into the housing assembly that can damage it over time.
