Due to the robust direct design of the Hawk Pressure Reducing Valve, more often than not it is factors other than the valve itself which cause malfunctions. Here we shall illustrate problems that may arise In scenarios which may involve the valve, but are not a consequence of the valve and its design.

Pressure Reducing Valve Stops Flow :
Caused by the valve being fitted wrongly, back to front. Check the arrow on the valve body and fit correctly.

Outlet Pressure is Below Setting :
Directionally wrong adjustment.

The Inlet pressure could be below the desired set valve, or could have dropped since the last time it was set.

Pressure Guage could be faulty.

Drop in outlet pressure when there is downstream flow This is quite normal, and not a fault. It is due to the head-toss in the pipeline on the inlet side, and also the inherent head-loss across the valve. For more details please refer to the section about head-loss calculation above. However, if the head-loss Is too large, it means that the valve size selected is too smalt or the pipe diameter is not large enough

Outlet Pressure Is Above Setting :
The outlet pressure setting lies outside the limits of the valve, as explained in the "Adjustment Range" charts of the valve.

Setting was done when water was flowing through the valve. To correct this, please reset the valve properly, i.e. open the adjustment screw completely (anti-clockwise), open a tap downstream to bleed the system, close all taps, then reset the valve to the desired pressure.

Pressure Guage could be faulty.

Back Pressure in the system. This could tie caused due to a back pressure build up in a heater or any other such appliance where water is heated and expands (100 litres of water at 15°C expands to 102 liters at 70°C). In normal circumstances, this is prevented by a Non Return Valve on the inlet side of the heater, but when this valve is faulty or worn or could be working erratically due to bad spring quality/seat mechanism.

Inlet And Outlet Pressure Are Equal
Incorrect pressure setting,caused due to excessive tightening of the adjusting screw. To rectify,slacken the screw and reset.

Damage to the internals of the internals of the valve due to a "pressure-slam" or "water-hammer".Seating & seat cage mechanism in the valve could be bent/broken.

Bypass allows the inlet pressure to pass into the outlet side,due to faulty isolation valves.This makes what is wrongly considered to be a safety feature into the problem itself. WE DO NOT RECOMMEND USING A BYPASS SYSTEM WITH OUR VALVES,AS IT IS ALMOST NEVER POSSIBLE FOR THE VALVE TO SHUT DOWN FLOW COMPLETELY,UNLIKE SOME MAKES OF VALVES WHICH SHUT OFF FLOW IN CIRCUMSTANCES NOT IDEAL FOR THEIR FUNCTIONING.

Only one of the inlet pipelines (either hot/cold water) is fitted with a Pressure Reducing Valve.There could be leakage into the other pipeline through a mixer.