Pressure Problems
NoPressure problems can be a challenge to isolate. Presuming that there is water flow to the high pressure pump, there are 3 components that are factors in building pressure.
1. Pressure control valve (needle valve). If there is a build up of scale on the needle and seat, this can prevent the valve from creating enough restriction in the flow to build pressure.
1. You can inspect the needle by loosening off the cap-nut behind the knob, and winding the knob all the way out until the needle assembly come out of the valve body. The needle should be clean and shiny. If not, wipe it clean with a rag.
2. Cleaning the scale out of the valve body is a bit trickier. You don't want to stick anything hard into the valve body, because even a small scratch can wreck the seat. Replace the needle and tighten up the cap nut until the turning resistance on the knob feels familiar. Wind the stem all the way in. Over tighten the needle to break apart the built up scale on the seat. To do this, wrap the knob with a rag, and use some large pliers to tighten the knob a little, 5 to 10 degrees. After this, wind out the knob all the way and run the boost pump for 5 minutes to flush away any scale in the valve. Wind the valve in and out a few times, while you are doing this.
This usually takes care of the problem, if it is due to scale in the pressure control valve.
2. Pressure relief valve. The pressure relief valve is a safety device that dumps water overboard in the event of an over pressure situation. This valve has a stainless steel spring. Unlike a high-carbon steel spring, it doesn't hold a permanent spring memory. Eventually, the spring may relax and start dumping water below operating pressure. Normally when the valve needs adjustment, the pressure will suddenly drop to around 200psi. Winding more pressure in will not increase the pressure on the gauge. Unwinding the pressure valve, all the way, and then winding pressure on again will start to build pressure (past 200 psi). If this is the case, follow the instructions below. This works best with two people.
1. Loosen the hose clamp on the pressure relief valve fitting, so that the hose can twist, on the fitting.
2. Loosen the thin locking nut on the pressure relief valve, then wind the cap-nut all the way in, until it bottoms out in the valve body.
3. Start up the system normally, with the product water on sample. Bring the pressure up to 1050psi. Have one person monitor the gauge.
4. Loosen off the cap nut, on the pressure relief valve. Keep going until the pressure drops. Sometimes the needle moves on the gauge a bit, then the pressure suddenly drops to <200psi.
5. With the system still running, you can drop the pressure on the pressure control valve, then bring it back up. It should dump pressure somewhere between 950psi and 1050psi. Adjust the cap-nut on the pressure relief valve, until the pressure dumps in the correct pressure range.
6. When the system is performing normally, you can tighten the lock nut on the pressure relief valve, and snug up the hose clamp.
3. High Pressure Pump. The high pressure pump is the least likely component to be a problem in the high pressure circuit. There are two potential problems that occur with the high pressure pumps.
The first is plunger seals. The plunger seals are the high pressure water seals that prevent water from getting past the ceramic plungers. The typical service life on these is long enough that they only wear out in commercial operations, however, in the event that the high pressure pump is run for extended periods of time without sufficient water flow, these seals can be damaged by the resulting build up of heat. When there is a problem with the plunger seals, water will leak from the vents on the bottom of the pump, where the wet manifold meats the crank-case.
The second is the check valves. There are 2 check valves for each of 3 plungers, an inlet valve and an outlet valve. These are located behind the 6 cylindrical caps with the hex sockets. The check valves are a poppet and seat with a spring in a cone shaped plastic cage. Sometimes some debris builds up between the poppet and seat and it fails to close properly, or fails to open.
1. Remove the cap, using a 3/8 inch alan key. Using pliers, grasp the small cylindrical protrusion on the valve cage and gently rock it out of the valve chamber. Inspect the valve. It should be clean and shiny. The poppet should lift off the seat easily and the spring should return it to the seat smoothly. The mating surfaces of the poppet and seat should be clean and shiny. If there is any debris or discolouration on the valve, clean it up in fresh water. An old toothbrush can be helpful in cleaning the poppet and seat. Replacement valve kits are available, but most of the time valve problems can be addressed by cleaning.
2. Check the inside of the valve chamber. Remove any salt or scale. Make sure that the o-ring at the base of the chamber is clean and undamaged. Insert the clean valve and replace the valve cap. Repeat the procedure with the other 5 valves.
1. Pressure control valve (needle valve). If there is a build up of scale on the needle and seat, this can prevent the valve from creating enough restriction in the flow to build pressure.
1. You can inspect the needle by loosening off the cap-nut behind the knob, and winding the knob all the way out until the needle assembly come out of the valve body. The needle should be clean and shiny. If not, wipe it clean with a rag.
2. Cleaning the scale out of the valve body is a bit trickier. You don't want to stick anything hard into the valve body, because even a small scratch can wreck the seat. Replace the needle and tighten up the cap nut until the turning resistance on the knob feels familiar. Wind the stem all the way in. Over tighten the needle to break apart the built up scale on the seat. To do this, wrap the knob with a rag, and use some large pliers to tighten the knob a little, 5 to 10 degrees. After this, wind out the knob all the way and run the boost pump for 5 minutes to flush away any scale in the valve. Wind the valve in and out a few times, while you are doing this.
This usually takes care of the problem, if it is due to scale in the pressure control valve.
2. Pressure relief valve. The pressure relief valve is a safety device that dumps water overboard in the event of an over pressure situation. This valve has a stainless steel spring. Unlike a high-carbon steel spring, it doesn't hold a permanent spring memory. Eventually, the spring may relax and start dumping water below operating pressure. Normally when the valve needs adjustment, the pressure will suddenly drop to around 200psi. Winding more pressure in will not increase the pressure on the gauge. Unwinding the pressure valve, all the way, and then winding pressure on again will start to build pressure (past 200 psi). If this is the case, follow the instructions below. This works best with two people.
1. Loosen the hose clamp on the pressure relief valve fitting, so that the hose can twist, on the fitting.
2. Loosen the thin locking nut on the pressure relief valve, then wind the cap-nut all the way in, until it bottoms out in the valve body.
3. Start up the system normally, with the product water on sample. Bring the pressure up to 1050psi. Have one person monitor the gauge.
4. Loosen off the cap nut, on the pressure relief valve. Keep going until the pressure drops. Sometimes the needle moves on the gauge a bit, then the pressure suddenly drops to <200psi.
5. With the system still running, you can drop the pressure on the pressure control valve, then bring it back up. It should dump pressure somewhere between 950psi and 1050psi. Adjust the cap-nut on the pressure relief valve, until the pressure dumps in the correct pressure range.
6. When the system is performing normally, you can tighten the lock nut on the pressure relief valve, and snug up the hose clamp.
3. High Pressure Pump. The high pressure pump is the least likely component to be a problem in the high pressure circuit. There are two potential problems that occur with the high pressure pumps.
The first is plunger seals. The plunger seals are the high pressure water seals that prevent water from getting past the ceramic plungers. The typical service life on these is long enough that they only wear out in commercial operations, however, in the event that the high pressure pump is run for extended periods of time without sufficient water flow, these seals can be damaged by the resulting build up of heat. When there is a problem with the plunger seals, water will leak from the vents on the bottom of the pump, where the wet manifold meats the crank-case.
The second is the check valves. There are 2 check valves for each of 3 plungers, an inlet valve and an outlet valve. These are located behind the 6 cylindrical caps with the hex sockets. The check valves are a poppet and seat with a spring in a cone shaped plastic cage. Sometimes some debris builds up between the poppet and seat and it fails to close properly, or fails to open.
1. Remove the cap, using a 3/8 inch alan key. Using pliers, grasp the small cylindrical protrusion on the valve cage and gently rock it out of the valve chamber. Inspect the valve. It should be clean and shiny. The poppet should lift off the seat easily and the spring should return it to the seat smoothly. The mating surfaces of the poppet and seat should be clean and shiny. If there is any debris or discolouration on the valve, clean it up in fresh water. An old toothbrush can be helpful in cleaning the poppet and seat. Replacement valve kits are available, but most of the time valve problems can be addressed by cleaning.
2. Check the inside of the valve chamber. Remove any salt or scale. Make sure that the o-ring at the base of the chamber is clean and undamaged. Insert the clean valve and replace the valve cap. Repeat the procedure with the other 5 valves.
