Chemical Pump Shutoff Valve

[Pakman]

I'm preparing to rebuild my chemical pump on an older Bridgepoint Systems TM. It primes, but then once I set the the metering valves to chemical the metering ball sits between 2 and 4 with my wand valve closed. When I open the wand the ball doesn't typically move much. At times this doesn't happen, but typically it does. My question is, would it be a good idea to put a shut-off valve somewhere in line to keep the high pressure during tile cleaning from reaching the pump? I was thinking an inline ball valve, but if this was a good idea it seems they would have thought to do it from the factory, so I just want to make sure I'm not doing something that I shouldn't.

Thanks!

 

[wandwizard]

What kind of chemical pump is on there? It sounds like you have a bad diaphragm. I believe a bad check valve that stays open can also cause that issue and possibly a bad 3 way chemical valve. Rebuilding the chemical pump should solve the problem.

As far as having a shut-off valve between the pump and the chemical pump it definitely couldn't hurt. If you operate at higher pressures a lot to do tile and grout I suspect you almost certainly will have more problems with your chemical pump w/o a shut off valve. The old style chemical pump was rated for up to 800 psi maximum and frankly I think that is stretching the truth.

 

[Pakman]

What kind of chemical pump is on there? It sounds like you have a bad diaphragm. I believe a bad check valve that stays open can also cause that issue and possibly a bad 3 way chemical valve. Rebuilding the chemical pump should solve the problem.

As far as having a shut-off valve between the pump and the chemical pump it definitely couldn't hurt. If you operate at higher pressures a lot to do tile and grout I suspect you almost certainly will have more problems with your chemical pump w/o a shut off valve. The old style chemical pump was rated for up to 800 psi maximum and frankly I think that is stretching the truth.

Thanks Wizard. My truckmount is basically comparable to the old Legends from early 2000's and yes I do quite a bit of tile work. It has last step chemical injection. My plan was to rebuild the pump, replace lines, o-rings, and check valves. I did consider the check valve due to the problem being somewhat intermittent. I have also noticed a little water coming from the stem of the selector knob, so I probably need to make some adjustments there as well.

I guess my main concern is I will be starving the pump in a sense, and I wonder if this will cause damage.

 

[wandwizard]

The new GP chemical pumps that are rated for higher pressures have a built in shut off valve. I can only figure the reason is so the diaphragm doesn't get damaged under those high pressures. I can't see any other reason for it really. A hole can develop in the diaphragm so it seems logical to me that shutting it off while working with higher pressures would make the chem pump last longer w/o problems. There is no way you can starve the chem pump. It works totally off the pressure of the high pressure pump.

I replaced almost all of my chemical feed system last year including changing to the new style GP pump. Mine is the lower pressure model that I think is rated for 1500 psi because it has no shutoff valve. Again, I still think that's stretching the truth. I haven't had any problems yet caused by the chem pump itself, but I don't do a lot of tile so I'm typically way under the max pressure limit and my machine tops out at around 1,000 psi anyway. They do make a higher pressure model that's being put on machines more geared for higher pressures that comes with a shut off valve already installed. Personally I think it's a good idea if they would do the same for the 1,500 psi model as well.

Here is a .pdf of the newer General pulse pump. It is supposed to be rated for 1500 psi w/o the shutoff valve engaged and up to 3,000 psi with it engaged. Personally I think it should be engaged if doing anything requiring higher pressures. If I run into trouble with my new pump I may put something similar on mine. http://generalpump.cazarin.com/wp-content/uploads/2017/10/100152-PulsePump.pdf

https://www.generalpump.com/product/100152/

 

[Pakman]

The new GP chemical pumps that are rated for higher pressures have a built in shut off valve. I can only figure the reason is so the diaphragm doesn't get damaged under those high pressures. I can't see any other reason for it really. A hole can develop in the diaphragm so it seems logical to me that shutting it off while working with higher pressures would make the chem pump last longer w/o problems. There is no way you can starve the chem pump. It works totally off the pressure of the high pressure pump.

I replaced almost all of my chemical feed system last year including changing to the new style GP pump. Mine is the lower pressure model that I think is rated for 1500 psi because it has no shutoff valve. Again, I still think that's stretching the truth. I haven't had any problems yet caused by the chem pump itself, but I don't do a lot of tile so I'm typically way under the max pressure limit and my machine tops out at around 1,000 psi anyway. They do make a higher pressure model that's being put on machines more geared for higher pressures that comes with a shut off valve already installed. Personally I think it's a good idea if they would do the same for the 1,500 psi model as well.

Here is a .pdf of the newer General pulse pump. It is supposed to be rated for 1500 psi w/o the shutoff valve engaged and up to 3,000 psi with it engaged. Personally I think it should be engaged if doing anything requiring higher pressures. If I run into trouble with my new pump I may put something similar on mine. http://generalpump.cazarin.com/wp-content/uploads/2017/10/100152-PulsePump.pdf

https://www.generalpump.com/product/100152/

Wow Randy, great info! Thanks for taking the time...I really appreciate it.

 

[Ara Klujian]

The new GP chemical pumps that are rated for higher pressures have a built in shut off valve. I can only figure the reason is so the diaphragm doesn't get damaged under those high pressures. I can't see any other reason for it really. A hole can develop in the diaphragm so it seems logical to me that shutting it off while working with higher pressures would make the chem pump last longer w/o problems. There is no way you can starve the chem pump. It works totally off the pressure of the high pressure pump.

I replaced almost all of my chemical feed system last year including changing to the new style GP pump. Mine is the lower pressure model that I think is rated for 1500 psi because it has no shutoff valve. Again, I still think that's stretching the truth. I haven't had any problems yet caused by the chem pump itself, but I don't do a lot of tile so I'm typically way under the max pressure limit and my machine tops out at around 1,000 psi anyway. They do make a higher pressure model that's being put on machines more geared for higher pressures that comes with a shut off valve already installed. Personally I think it's a good idea if they would do the same for the 1,500 psi model as well.

Here is a .pdf of the newer General pulse pump. It is supposed to be rated for 1500 psi w/o the shutoff valve engaged and up to 3,000 psi with it engaged. Personally I think it should be engaged if doing anything requiring higher pressures. If I run into trouble with my new pump I may put something similar on mine. http://generalpump.cazarin.com/wp-content/uploads/2017/10/100152-PulsePump.pdf

https://www.generalpump.com/product/100152/

That will definitely be the next pump I get. Unless the pricing is absurd, I will stick to a fabricated version.