Tried a permeate pump on my new RO system. Didn't work so great.

[BDrivenByDemons]

I bought the ERP-500 permeate pump and the ASV90 shut off valve after reading quite a bit here. It doesn't come close to the pressure/flow my old watts setup with an aquatec booster pump had. I still have the aquatec pump and would like to utilize it for maximum pressure on this new system but I'm not sure how to hook it up. My old system didn't have an ASV that I know of and the pump was controlled by a pressure switch in the tank line. I'm thinking the aquatec will replace the ERP500 but how do the pressure switch and ASV play nice together? This has to be simple but I'm confused. I dont want the pump to run continuously.

 

[BDrivenByDemons]

I think I figured it out. I need an electronic shut off for the supply that closes once the tank pressure is satisfied.

 

[Sponsor]

 

[Bannerman]

You didn't specify which model of Watts RO system you have, but in reviewing the flow diagram for the various models including the 525P which is equipped with a booster pump, each model utilizes an ASOV to shut off water production once the water in storage has risen to a specific percentage of pressure in relation to the supply pressure. Most standard ASOVs will stop production when the RO storage pressure has risen to ~60% of the supply pressure whereas your ASOV90 valve will stop production when RO pressure is ~90% of the supply pressure. Since you are not aware if the unit was already equipped with an ASOV, I suspect the exsisting one still remains and is continuing to limit the storage pressure to 60% which is defeating any benefit of the 90% ASOV.

The 525P diagram shows the booster pump located directly after the stage 1 filter, and so will be boosting the supply pressure to stages 2, 3 and the membrane. Since the ASOV will be sensing the higher supply pressure after the booster pump, even a 60% valve should cause the RO storage pressure to be significantly higher than your exsisting system without a booster pump.

 

[BDrivenByDemons]

You didn't specify which model of Watts RO system you have, but in reviewing the flow diagram for the various models including the 525P which is equipped with a booster pump, each model utilizes an ASOV to shut off water production once the water in storage has risen to a specific percentage of pressure in relation to the supply pressure. Most standard ASOVs will stop production when the RO storage pressure has risen to ~60% of the supply pressure whereas your ASOV90 valve will stop production when RO pressure is ~90% of the supply pressure. Since you are not aware if the unit was already equipped with an ASOV, I suspect the exsisting one still remains and is continuing to limit the storage pressure to 60% which is defeating any benefit of the 90% ASOV.

The 525P diagram shows the booster pump located directly after the stage 1 filter, and so will be boosting the supply pressure to stages 2, 3 and the membrane. Since the ASOV will be sensing the higher supply pressure after the booster pump, even a 60% valve should cause the RO storage pressure to be significantly higher than your exsisting system without a booster pump.

Apologies. My old system was a watts WP-4V and after looking at it I see there is an integrated ASOV on top. My new setup is a Ukoke RO8-L and I did remove the existing ASOV to replace it with the 90%. I'm aware of the different hookup layout of the 90% valve. I also bought the permeate pump on the fact it "sees" a lower tank pressure and helps with TDS. My well is currently set for 45/65 and even at the full 65 the 90% ASOV would only give me 40psi in my RO tank when it should be closer to 58.

Since I wasn't aware the old watts system had an ASOV I eliminated it from the ukoke when replaced the permeate pump with my old aquatec 6800. I already have a tank shut off switch for the aquatec and have ordered an electronic shut off to kill the supply when tank pressure is satisfied. It just seems like the "right" way to do it with the booster. I suppose I could put the old ASV back in but I'll be limited in setting my booster and tank switch pressures that way (if I'm thinking correctly). EX - I set the booster to 100psi and the tank switch to 70, the old ASV will cut off supply @ 60 before the tank switch can be opened and the pump will run forever. I'm just eliminating that headache, again - if I'm thinking right.

 

[Bannerman]

My well is currently set for 45/65 and even at the full 65 the 90% ASOV would only give me 40psi in my RO tank when it should be closer to 58.

65 psi is when the well's pressure switch will shut off the well pump. Since the RO system will be consuming water while in production, that water will be supplied by the well system's pressure tank so the pressure will immediately begin to fall from 65 down to 45 psi even while no other water is utilized anywhere in the home. The speed in which the pressure will fall will be largely conditional on the drawdown capacity of the well system's pressure tank.

I anticipate the 40 psi supplied to your RO faucet, is due to the variance in supply pressure between 65 down to 45 psi and then back up to 65 psi that will likely occur numerous times while the RO unit is in production.

The ERP-500 is appropriate for RO systems equipped with up to a 50 GPD membrane. As the Ukoke-R-08L appears to be equipped with a 75 GPD membrane, that could be part of the reason why the ERP-500 is not performing satisfactorily. Suggest replacing the 75 GPD membrane with a 50 GPD version, which will also allow the drain flow restrictor to be replaced with an appropriate lower flow rate restrictor.

While both a booster pump and permeate pump maybe utilized on the same system, I suspect that brand of RO system maybe produced offshore, so I am reluctant to recommend supplying boosted pressure (usually 80 psi+) to components of unknown quality.

 

[BDrivenByDemons]

65 psi is when the well's pressure switch will shut off the well pump. Since the RO system will be consuming water while in production, that water will be supplied by the well system's pressure tank so the pressure will immediately begin to fall from 65 down to 45 psi even while no other water is utilized anywhere in the home. The speed in which the pressure will fall will be largely conditional on the drawdown capacity of the well system's pressure tank.

I anticipate the 40 psi supplied to your RO faucet, is due to the variance in supply pressure between 65 down to 45 psi and then back up to 65 psi that will likely occur numerous times while the RO unit is in production.

The ERP-500 is appropriate for RO systems equipped with up to a 50 GPD membrane. As the Ukoke-R-08L appears to be equipped with a 75 GPD membrane, that could be part of the reason why the ERP-500 is not performing satisfactorily. Suggest replacing the 75 GPD membrane with a 50 GPD version, which will also allow the drain flow restrictor to be replaced with an appropriate lower flow rate restrictor.

While both a booster pump and permeate pump maybe utilized on the same system, I suspect that brand of RO system maybe produced offshore, so I am reluctant to recommend supplying boosted pressure (usually 80 psi+) to components of unknown quality.

But how would you control the booster if also used with a permeate pump? It sounds like an ultimate yet expensive setup but the pump would run forever.

 

[Bannerman]

Why do you think a booster pump cannot continue to be controlled by a pressure switch, just as you had planned to do without a permeate pump?

A permeate pump in itself will not boost the storage pressure, so a 60% ASOV will continue to stop production when the storage pressure has risen to 60% of the supply pressure. Since most booster pumps will boost the supply pressure to between 80-100 psi, if the pressure from the pump remains consistant, then 60% will be somewhere between 48-60 psi, so with a 50 psi booster pump cutoff pressure, that should be more than sufficient to supply the ~1 GPM flow rate most RO faucets and water dispensers are designed to deliver.

A 60% ASOV is normally utilized when no permeate pump is installed since back-pressure from the storage tank will cause the membrane's production rate to progresively decrease as back-pressure increases. Because the drain flow rate is governed by a flow restrictor, the drain flow rate will remain constant regardless of the variance of production flow through the membrane, so a drain flow rate that may equal 2-gallons for every gallon of RO water produced while back-pressure is minimal, maybe 8-gallons or more to drain per gallon produced while the storage tank is almost filled and back-pressure on the membrane is greatest.

A permeate pump is utilized to pump the RO water directly exiting the membrane into the storage tank, which will significantly reduce back-pressure on the membrane. This will allow greater pressure differential across the membrane, which will increase the membrane's production efficiency to allow it to produce higher quality RO water in less time. Since the membrane will see lower back-pressure, the production rate vs drain rate will remain more consistant regardless of the pressure within the storage tank. Since the storage tank will be replenished in less time, the unit will require less operating time each day to produce the equivalent quantity of RO water your family now consumes each day, thereby further reducing the quantity of water which is flowing to drain from the RO unit.

A 90% ASOV is often utilized to acheive greater storage capacity and pressure when using a permeate pump since the drain rate vs production rate will remain consistant even while the unit is producing RO when the storage pressure is 90% of the supply pressure.

 

[BDrivenByDemons]

Why do you think a booster pump cannot continue to be controlled by a pressure switch, just as you had planned to do without a permeate pump?

A permeate pump in itself will not boost the storage pressure, so a 60% ASOV will continue to stop production when the storage pressure has risen to 60% of the supply pressure. Since most booster pumps will boost the supply pressure to between 80-100 psi, if the pressure from the pump remains consistant, then 60% will be somewhere between 48-60 psi, so with a 50 psi booster pump cutoff pressure, that should be more than sufficient to supply the ~1 GPM flow rate most RO faucets and water dispensers are designed to deliver.

A 60% ASOV is normally utilized when no permeate pump is installed since back-pressure from the storage tank will cause the membrane's production rate to progresively decrease as back-pressure increases. Because the drain flow rate is governed by a flow restrictor, the drain flow rate will remain constant regardless of the variance of production flow through the membrane, so a drain flow rate that may equal 2-gallons for every gallon of RO water produced while back-pressure is minimal, maybe 8-gallons or more to drain per gallon produced while the storage tank is almost filled and back-pressure on the membrane is greatest.

A permeate pump is utilized to pump the RO water directly exiting the membrane into the storage tank, which will significantly reduce back-pressure on the membrane. This will allow greater pressure differential across the membrane, which will increase the membrane's production efficiency to allow it to produce higher quality RO water in less time. Since the membrane will see lower back-pressure, the production rate vs drain rate will remain more consistant regardless of the pressure within the storage tank. Since the storage tank will be replenished in less time, the unit will require less operating time each day to produce the equivalent quantity of RO water your family now consumes each day, thereby further reducing the quantity of water which is flowing to drain from the RO unit.

A 90% ASOV is often utilized to acheive greater storage capacity and pressure when using a permeate pump since the drain rate vs production rate will remain consistant even while the unit is producing RO when the storage pressure is 90% of the supply pressure.

Ok this makes sense. IDK why my brain isn't working when it comes to this topic. I'm going to try a few things this week... I'll probably try without the permeate pump first and see how the TDS reads.

 

[Bannerman]

The Aquatec 6800 is appropriate for RO systems up to 50 GPD. As it seems the Ukoke-R-08L is equipped with a 75 GPD membrane, your booster pump will be undersized unless your RO membrane and drain flow restrictor are first replaced with lower capacity versions.

I do not recommend utilizing the ASOV90 without a permeate pump. As previously explained, without a permeate pump to prevent back-pressure on the membrane, the membrane's production rate will continue to decline as back-pressure continues to increase.

While the ratio of brine drain discharge to RO water maybe only ~2 gallons for each gallon of RO water produced while back-pressure is minimal, the ratio will potentially exceed 20 gallons discharged for each gallon produced when the storage pressure is approaching 90% of the supply pressure. In addition to a greater volume of waste flow to your septic system, the RO unit will need to operate much longer each day, just to satisfy your current usage requirements. If not utilizing the permeate pump, improve efficiency and performance by reinstalling the original 60% ASOV.

Although it is ultimately your choice whether or not to risk boosting the supply pressure to the Ukoke-R-08L, again for the reasons explained earlier, I advise against boosting the pressure to components of unknown quality.

 

[BDrivenByDemons]

The Aquatec 6800 is appropriate for RO systems up to 50 GPD. As it seems the Ukoke-R-08L is equipped with a 75 GPD membrane, your booster pump will be undersized unless your RO membrane and drain flow restrictor are first replaced with lower capacity versions.

I do not recommend utilizing the ASOV90 without a permeate pump. As previously explained, without a permeate pump to prevent back-pressure on the membrane, the membrane's production rate will continue to decline as back-pressure continues to increase.

While the ratio of brine drain discharge to RO water maybe only ~2 gallons for each gallon of RO water produced while back-pressure is minimal, the ratio will potentially exceed 20 gallons discharged for each gallon produced when the storage pressure is approaching 90% of the supply pressure. In addition to a greater volume of waste flow to your septic system, the RO unit will need to operate much longer each day, just to satisfy your current usage requirements. If not utilizing the permeate pump, improve efficiency and performance by reinstalling the original 60% ASOV.

Although it is ultimately your choice whether or not to risk boosting the supply pressure to the Ukoke-R-08L, again for the reasons explained earlier, I advise against boosting the pressure to components of unknown quality.

I do appreciate your input on this. I did return the permeate pump and asv90 and grabbed a 50gpd 1:1 pentair membrane and electronic shut-off and pressure switch. Everything works much better.

 

[Leanman82]

I really don't understand how you guys understand these things. Do you guys have gauges or measurement techniques that help you assess your conclusions? I'm new to RO systems and it seems like a hobby when I read the knowledgeable posts in these forums.