So just curious why everyone says cartridge filters can't vaccume to waste? My pentair free and clear 75 has a pressure relief valve with a spout on top that can connect to a hose. I use it to drain all the time. Sure some ends up going to the return but most goes out of the spout. I'm under the impression that water is not going through the filter. Isn't that pretty close to the waste function of other filters?
Cartridge filter. Why do you say I can't vaccume to waste?
- Thread starter Mdh2861
- Start date
mdh,
Not sure about your specific filter, but none of the cartridge filters that I am aware of are designed to in any way bypass the filter. While it is true you could open the filter drain plug, a lot of water will still pass through the cartridges. If you are just lowering the water, that would not be a big deal, but vacuuming to waste indicates that the water has debris or chemicals that you do not want to end up in your filter, like Floc, etc.
A good way around this issue is to just add a 3-way valve in the input line to the filter. This would allow you to divert the dirty water to waste.
Thanks,
Jim R.
Not sure about your specific filter, but none of the cartridge filters that I am aware of are designed to in any way bypass the filter. While it is true you could open the filter drain plug, a lot of water will still pass through the cartridges. If you are just lowering the water, that would not be a big deal, but vacuuming to waste indicates that the water has debris or chemicals that you do not want to end up in your filter, like Floc, etc.
A good way around this issue is to just add a 3-way valve in the input line to the filter. This would allow you to divert the dirty water to waste.
Thanks,
Jim R.
Here is a picture of the valve with the hose hookup. The water goes into the filter and through pressure gets pressed through the filter fingers through the filter into the return. It would seem that water that empties through the pressure relief valve is not going through the filter. That's more of a question than a statement 
This is what Jim is talking about up above. I turn the 3 way valve and it completely bypasses the filter. It's an extra step at build time that many skip. Currently it's going to a drywall but I am going to redirect it to the yard.
mdh,
That part in your pic is the air vent valve. It is there to let you remove any trapped air out of the filter.
My "guess" is that at least 50% of any water entering the filter will go through the cartridges and back to the pool before any water goes up and out the air vent. The air vent would allow you to dump some water, but that is not what it is for. I for one, would never try to use it to "Vacuum to waste."
Thanks,
Jim R.
That part in your pic is the air vent valve. It is there to let you remove any trapped air out of the filter.
My "guess" is that at least 50% of any water entering the filter will go through the cartridges and back to the pool before any water goes up and out the air vent. The air vent would allow you to dump some water, but that is not what it is for. I for one, would never try to use it to "Vacuum to waste."
Thanks,
Jim R.
gingrbredman
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- Jun 10, 2020
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I have the same filter, and it works the same as you note, but is not designed to "vacuum to waste", it is simply an air vent as @Jimrahbe mentioned above. Does it take some water out of the filter? Yes, it does, and you could likely sit there for a while and take quite a bit of water out if you wanted to, but that water has already gone through the filters.
To just put it all together, it is not a shortcoming of the cartridge filter, it is the fact there is not a valve there to divert the water from going in there first, so it can be sent to waste, again, before it hits the filters.
You might get 5gpm through that port. The rest is going through the cartridge and back to the pool. The only way to truly vacuum to waste with your system would be to remove the top of the filter tank and let the water flow. Messy. Could flood your motor.Here is a picture of the valve with the hose hookup. The water goes into the filter and through pressure gets pressed through the filter fingers through the filter into the return. It would seem that water that empties through the pressure relief valve is not going through the filter. That's more of a question than a statement
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