Pump PSI Drops from 1100 to 400

[Roz]

We have a CAT310B pump stand that starts at 1100psi (normal setting) and then drops to 400psi when the wand trigger is pulled.

Normally the drop is 100psi more or less.
We changed the brass regulator and the entire handle from the bay hose yet issue persists. We removed the wand and blew out the hose with an open end at the bay in case there was junk inside the hose. The system is from Istobal (who is no help) - they purchased the system/company so not surprised that no one there seems to have any additional suggestions.

You can see the new regulator in the pic. Anyone have additional ideas or have experienced the same issue? We checked the regulator that it was replaced correctly.
Thx.

 

[MEP001]

Loss of pressure is from loss of flow. Your tip could be eroded or damaged, the new regulator could have debris in it, you could have a bad high-pressure check valve somewhere, a bad inlet check valve, a leak on the inlet side allowing the pump to draw air, or there could be a problem with the pump.

 

[Randy]

My wild ass guess would be you have a pump problem, valves or seals. I'd pull the valves and check for any debris in the valves, then pull the pump head and check for head wash out. If the head looks good I'd replace the seals.

 

[mjwalsh]

Once upon a time ... one of us workers grabbed the wrong replacement nozzle. You might want to verify that there was no mistake made with a replacement nozzle.

 

[Jim64]

Had the same problem with cat 310. My pressure dropped from 1100 to 700 when handle pulled. I replaced regulator, seals, and checked valves for trash. Sent the pump head to be bored and sleeved and now it runs like a new pump. Cost $160 plus shipping both ways.

 

[Roz]

We tested each component and finally determined that the issue was within the pump. A new 310 and things are working again.