Newbee Questions On Nozzle and pump pressure.

[lilb93]

The pumps are 310 cats with 5HP Balador motors. The Nozzles that are on are 1507 MEG. Have the pressure set at 1300 PSI.
When they do not pull the gun handle in the bay the pressure jumps to 1900 PSI. when handle pulled it goes to 1300 Appx. Is that normal??
Only on one bay I could turn up the pressure to max (Unloader all the way down. Max pressure 1100 Psi When you do not pull the gun it jumps to 2200 PSI Changed the tip or nozzle with a new one no difference. Has me stumped..
Thanks

 

[sparkey]

It sounds like you have your unloader set at 2200 psi. When the pull the trigger you don't have enough flow to maintain 2200 psi. Remember pumps create flow not pressure. Resistance to flow causes pressure. I would start by replacing the nozzles just to be sure they are not worn. If that doesn't fix the issue you may need to rebuild the pump.

 

[lilb93]

Yes I did replace the nozzle with a new one. Will have to get a rebuilding kit Have to check he left a lots of extra spare parts there.

 

[2Biz]

Sounds like you have a bad unloader/regulator. You shouldn't see no more than 50 psi difference when the unloader bypasses. You've replaced the nozzle, eliminating it as the culprit. Try replacing the unloader/regulator as the next step. If you're able to make 2200 psi, it doesn't sound like your pump is bad.

 

[Randy]

I run my pumps at 1500psi with a 1505 nozzle. The 05 nozzle puts out 3.10 gpm at 1500 psi. The 07 nozzle puts out 4.30 gpm at 1500 psi.

 

[mrfixit]

The bypass/unloader/balanced regulator is bad.. The other could be stuck... Many of them can be rebuilt for cheap. I did one of mine recently.. Pressures nice and even all the time now.

 

[MEP001]

If there's something wrong with the pump that's preventing the pressure from going above 1100 with the trigger pulled, you can crank the regulator all the way up and it won't increase the pressure. When the trigger is released, the flow drops and the pressure goes way up. That means the regulator is working and you have a problem with the pump.

 

[2Biz]

If the regulator/unloader was good, he shouldn't see 2200 psi? It should maintain a set pressure.

 

[mrfixit]

I could see that flow could be related to the last problem.

Too big of a nozzle could cause that due to excess flow when gun open. I suppose it could happen for reasons other than nozzle tip, something related to flow being higher than normal on output. Or lower on inlet?

Nozzle? Gun? Pump?, incoming water?

You could try a smaller nozzle to see the result, but open the unloader more first! Smaller nozzle will increase the pressure!

Examine how the water and pressure come out of the wand how is it different compared to the others. Is there high pulsation,

When regulators/ unloaders are working your pressure will barely have a noticable change when the trigger is cycled during normal operation.

Its not normal to jump to 1900 on the others, repair or replace the unloaders, inspect thier operation and installation. The pressure swing is unneeded stress on the system.

Let us know what you find.

 

[2Biz]

I run Giant Unloaders and 2506 nozzles @ 1200 psi. When you release the trigger the pressure jumps about 50 psi with a new unloader. Over time, the bypass pressure will increase, which will let you know to either service or change the unloader/regulator. I've had them (all at once) jump to 1900 psi bypass. (The bypass valve sticks) Changing the unloader out with a new one has always solved the problem.

2506 nozzles run about 3gpm. I don't know anyone who uses 07 nozzles. Cutting back to an 06 nozzle will save you money in water and sewage. At 1200 psi, there is a .6 gpm difference between an 07 and 06 tip. Or about 16% if I did the math right....

 

[MEP001]

If the regulator/unloader was good, he shouldn't see 2200 psi? It should maintain a set pressure.

Because he would be cranking the regulator beyond a pressure setting that the pump can make with the trigger pulled, so it's having no effect until the trigger is released. It's POSSIBLE that the regulator is bad, but it's much more probable that there's an issue with the pump. The easiest way to confirm would be to tie off the trigger and adjust the pressure back down until the gauge drops, then turn it up just until the gauge stops increasing and see if the pressure no longer shoots up with the trigger released.