Procedure to set Hot Water PRV
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DB500-PGN-2
COBRA Bailout System
23 May 2019
Page 2 of 3
Figure 1 - Test equipment
See figure 1.
Fit the test plug (DB5003843), test nut (DB5003844) and o-ring (E13330) to the hot water relief valve DB5002335
as shown in figure 1. These items are contained in the COBRA Tool and Test Kit. Fit a 3/8” UNF plug to the
outlet of the relief valve.
Connect an LP air supply and a calibrated LP gauge. Care should be taken when applying the pressure if a very
low range gauge is used until it is confirmed that the PRV will vent correctly.
NOTE:
Ensure that the 3/8” plug does not interfere with the spring inside the PRV. It may be preferable to fit
the Hot Water Inlet Hose from the COBRA set (which has a specially shortened 3/8” fitting) and fit a 9/16” UNF
blank to the other end of this hose.
Immerse the hot water relief valve in water (minimum depth to cover relief outlet).
Gently apply air pressure to the relief valve inlet and note the pressure reading when bubbles start to form in the
water
NOTE:
The reading is taken when the first bubbles begin to form. Any appreciable flow through the PRV will
cause a higher reading on the gauge due to the port size on the test fitting.
