Change set pressure, question

[garciaf]

I have a Dresser Consolidated 19000 (pressure relief valve) the model of the valve is 1-19110LCF-2-CC-MS-31-MT-FT-LA, 40 USGPM (WATER)
I saw the manual and establish the following (see image attached).
As you can see
19 is the model
110 diameter orifice decimals (0.110 in2)
L range of pressure that cover from 5 min to 290 max.

See image attached. accoring to the pressure there is a corresponding value of gpm.

I can set the valve in any range of these.
for example the valve actually set pressure is 186 psig and I want to change to 90 psig, that can be possible.
thank you for your time

 

[The Obturator]

The valve is suitable for that range of pressure. BUT the the set pressure will be limited to the range of the fitted spring. I doubt very much that you can change from current setting of 186 PSIG to 90 PSIG. You need the valve types spring selection charts to determine the new spring. More importantly, adjusting the set pressure also changes the flow rate. In this case by lowering the set pressure, the valve will pass considerably less flow. You need to do a new sizing calculation to see if the current valve is big enough for the intended flowrate.

Per ISO, only the term Safety Valve is used regardless of application or design.

 

[The Obturator]

I also need to add that if the valve is "UV/NB" Code Stamped, that resetting will need to be done by a "VR" stamp holder, whom will also need to amend/change the nameplate.

Per ISO, only the term Safety Valve is used regardless of application or design.

 

[ChemE08]

avalveman is correct. Changing set pressure of valves is not outside the realm or normal duties for PSV repair shops. As noted, the spring would have to be swapped out for the correct one (spring range) as defined by the spring charts. Keep in mind the reduced capacity impact and ensure that your valve still has enough capacity for the overpressure event.