Rinse normal, soap and wax selection causes loss of pressure

[CWdummy]

I have 6 bay self serve about 40 yrs old with Ginsan equipment and Cat 530 pumps. Fairly well maintained. I can fix most any problem. I have 3 bays that run normal on rinse, but if you switch to high pressure soap or wax, the pressure falls drastically and booms go to shaking and noise in equipment room. The wax and soap comes out, but at a very reduced pressure. when you pull trigger, it shakes even more, also with loss of pressure. The rinse water comes directly off city water. When soap or wax is selected, that water comes from a float tank which has the wax and soap tanks on each side with hydrominders. Common sense tells me the pumps are fine since everything is good on rinse. Good pressure with no vibration on rinse. Check valves are fine where soap/wax goes into pump . This has been going on for a couple months. I need to fix it. I am at my wits end.

 

[Randy]

Your starving the pumps for water or your pulling in air on HP Soap and Wax. Check the water flow to the pump from your make up water tank. Check to make sure any strainers are clear and check the operation of any check valves. Also check to be sure that the valves feeding water to the pumps is open. Make sure your not drawing in air on the Wax and HP Soap cycle.

 

[CWdummy]

I agree. I think its getting air pulled in from somewhere. I have eliminated starvation I believe

 

[Randy]

I agree. I think its getting air pulled in from somewhere. I have eliminated starvation I believe

Another thing you can try is to plug off the Soap and wax line off at the pump and plug the port and then the pump. If it runs smooth then you know it's either the soap or wax line that's drawing in air.

 

[Waxman]

Whenever this happens to my system it's because the screen is dirty in the soap and wax tank

 

[Dan kamsickas]

That is a bit before my time but, I believe, the plumbing on those units was the the same. You should have individual ball valves and check valves for each bay under the rinse tank. They should all be fed by the same manifold "box". I would suspect that those ball/check valve assemblies are not flowing properly because that would be the only thing that soap/wax have in common is the water from the rinse tank. As also said, you may be getting air sucked in on that hose but I think it's less likely. As old as the equipment is, you may want to replace the hoses and valves and do a good cleaning of the screens and manifold.

 

[CWdummy]

Whenever this happens to my system it's because the screen is dirty in the soap and wax tank

Well there are no screens in soap or wax tank. Nothing in there to screen out.

 

[Dan kamsickas]

Well there are no screens in soap or wax tank. Nothing in there to screen out.

You really need some screens.

 

[CWdummy]

You really need some screens.

I keep tanks clean, but I will put some in. Thanks.

 

[2Biz]

Do you have "Zero Pressure" regulators installed for the city pressure water to your pumps as you stated? If you do and even if you're soap and wax lines are plugged, the pump should not cavitate. In my opinion, air is getting into the system when either soap or wax solenoids open and could be the only thing causing cavitation?

 

[Greg Pack]

Is there a check valve or solenoid between the water storage tank and the pump? If so, have you changed it out?

 

[CWdummy]

Another thing you can try is to plug off the Soap and wax line off at the pump and plug the port and then the pump. If it runs smooth then you know it's either the soap or wax line that's drawing in air.

I am doing that this week. Will report back. Thx

 

[CWdummy]

Is there a check valve or solenoid between the water storage tank and the pump? If so, have you changed it out?

Yes. Have a check valve and it is good. I did put another one in just to make sure.

 

[CWdummy]

Do you have "Zero Pressure" regulators installed for the city pressure water to your pumps as you stated? If you do and even if you're soap and wax lines are plugged, the pump should not cavitate. In my opinion, air is getting into the system when either soap or wax solenoids open and could be the only thing causing cavitation?

I agree. Trying to figure out where air is getting in.

 

[Greg Pack]

Yes. Have a check valve and it is good. I did put another one in just to make sure.

I would at least do a flow test on the water inlet with a bucket. Heck you could disconnect a wire on the starter coil and select soap and wax and check flow. You should be able to fill a 5 gallon bucket in 60 seconds


Also, I just read the posts again, have you checked any pump internals? If not it's time to.I have had issues with cavitation before and had to change seals to get it to quit.

 

[2Biz]

Also, I just read the posts again, have you checked any pump internals? If not it's time to.I have had issues with cavitation before and had to change seals to get it to quit.

CWdummy said rinse works properly in his first post, he only gets pressure loss and cavitation when selecting soap and wax. If this is the case, I would think it rules out pump seals...

 

[Greg Pack]

CWdummy said rinse works properly in his first post, he only gets pressure loss and cavitation when selecting soap and wax. If this is the case, I would think it rules out pump seals...

I had a similar situation on my coleman pump unit with pressurized rinse and seals fixed it. If he has truly tried everything else it becomes a hail mary pass, but worth a try.

 

[CWdummy]

I would at least do a flow test on the water inlet with a bucket. Heck you could disconnect a wire on the starter coil and select soap and wax and check flow. You should be able to fill a 5 gallon bucket in 60 seconds


Also, I just read the posts again, have you checked any pump internals? If not it's time to.I have had issues with cavitation before and had to change seals to get it to quit.

Greg,
Pump works as normal on rinse. Would you agree this proves the pump internals are good and this problem is outside the pump?

 

[Greg Pack]

Greg,
Pump works as normal on rinse. Would you agree this proves the pump internals are good and this problem is outside the pump?

Have you checked EVERYTHING outside the pump? If so, it's time to start looking at the internals.

What would a tech do at this point? Either start inspecting/replacing valves,seals, and other internal components or replace the pump is what I think they would do.

 

[Randy]

I have 6 bay self serve about 40 yrs old with Ginsan equipment and Cat 530 pumps. Fairly well maintained. I can fix most any problem. I have 3 bays that run normal on rinse, but if you switch to high pressure soap or wax, the pressure falls drastically and booms go to shaking and noise in equipment room. The wax and soap comes out, but at a very reduced pressure. when you pull trigger, it shakes even more, also with loss of pressure. The rinse water comes directly off city water. When soap or wax is selected, that water comes from a float tank which has the wax and soap tanks on each side with hydrominders. Common sense tells me the pumps are fine since everything is good on rinse. Good pressure with no vibration on rinse. Check valves are fine where soap/wax goes into pump . This has been going on for a couple months. I need to fix it. I am at my wits end.

This has gone on long enough. What have you checked so far?