Trouble Shooting Cause of the High Pressure Pump Running Rough.
Begin by knowing the pump serial number and manufacture date which are both located on the metal tag attached to the the panel on the side of the enclosure.
Several types of causes can be kept in mind which cause a pump to run ‘rough’. Try to identify how best to understand what rough means? Is it loud? Does the pressure fluctuate or jump while it is running? Does the noise vary depending on the pumps output pressure? Are the two pulleys properly aligned? Is the pump leaking water below the brass head? How many hours on the pump? Has the oil ever been changed?
The most likely cause for a ‘rough’ running pump is debris in one of the 6 valves in the pump head. If the pump is recently installed, small debris from installation such as teflon tape or brass shavings can be the cause. These valves control the water flow inside the pump head as the pistons move back and forth. If debris gets caught up in one of the valves, it can cause the pump to run rough.
The valves can be accessed by removing the 6 large bolts (three on top and three on the side) of the brass head. They should be removed and inspected making sure there is nothing interfering with the function of the valve spring assembly. This will require a 27mm socket and it is suggested to use a long “breaker bar” to provide additional leverage. The bolts will be tight.
Once the bolts are removed, use a pair of needle nose pliers to remove the individual valves and the o-ring at the bottom of the port (one valve and one or-ring in each port). Check the spring assembly to ensure nothing is broken (plastic housing or spring assembly). If it is, it will need to be replaced. If not, check for obvious debris that may be preventing the assembly from completely opening or completely closing. Use compressed air to blow out the valve. In some cases, the debris may not be noticeable. Compressed air will assure the valve assembly is cleared.
While the bolts are removed, use compressed air to blow out all of the ports. They are all interconnected so air into any given port will circulate through the other ports. In some cases, the debris may have worked its way out of the valve but is still inside the port. Blowing out the all of the ports will help ensure nothing is left inside.
Put the o-ring and the valve back into each port, thread the bolt back in place and turn the pump on to check the results of the cleaning.
There are occasions where we have to do this several times on our bench at the factory even though there is no visible debris. It usually is corrected with the first cleaning but may take two or three times to get the debris out.
Other possibilities are low water supply causing cavitation within the pump head or broken or damaged crankcase inside the bare pump. A detailed explanation of the pumps functional irregularity might help narrow it down. A video is always helpful. Images are good but not as useful as a video.
