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The following instrucons are intended to ensure the proper funcon of the pressure relief valve (PRV). We

suggest the procedure be performed as a part of the twice yearly periodic maintenance schedule.

Cool and depressurize the steam tank.

Remove the yellow tubing guard surrounding the PRV.

Check that the sealing face and rod move freely by pulling the test ring. There will be spring resistance, but

the seal should open easily and travel smoothly. If the seal scks or the spring feels griy, the valve is

scaled and should be replaced.

Replace the yellow tubing guard.

Disconnect the green ll probe wire from the upper level probe (located on the le side of the steam tank).

Allow steam tank to over-ll. Watch the steam tank pressure gauge. Once the water closes the vacuum

breaker, the PRV should release water. Note the pressure displayed on the steam tank gauge when this

occurs. The pressure at the point of release should be 50psi.

Replace the green ll probe wire. Drain the steam tank unl the ll valve acvates.

Reheat the steam tank.

Remove the yellow tube guard and check the PRV for leaks. Listen for hissing. Replace the PRV if it will not

seal.

Replace yellow tube guard.

If you have a source of compressed air available, you can overpressure the steam tank using air instead of

water:

Remove a steam wand p. Pull the steam handle to the full on posion.

Slowly add air to the steam tank. Watch the steam tank pressure gauge. The pressure at the point of release

should be 50psi.

Complete the maintenance as shown above starng at 8.

An older gauge is potenally less reliable than when rst manufactured. Addionally, a steam tank gauge

that has exceeded its scale limit of 60psi may be damaged internally. If aer experiencing high pressure, the

gauge cannot return to the zero point, it has been damaged and should be replaced.

Gauge readings are less accurate the further they are from the center point of the readable scale. When

measuring readings near 50psi on a 60psi max gauge, the results may be as much as 10% o in either direc-

on. With that in mind, PRVs releasing at a gauge pressure anywhere between 45 and 55psi are acceptable.

The body of the PRV is mostly hollow, so open end wrenches and other pliers can cause the PRV to collapse

or distort during removal or installaon. Use only closed end wrenches on PRVs. Seal with red Locte.

Assembled steam tanks are pressure tested up to 75psi at the factory before the PRV is installed.

Pressure relief valve maintenance procedure

Synesso MVP Technical Manual

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