Pump psi too high for SWG?

[dswwpb]

Asked this question in a different thread but it was buried in 3 pages and it didn't get much response. The RJ30+ arrived today and I see a warning on the cell that says do not exceed 10 PSI. With my single speed 1 HP pump the pressure gauge on the top of the filter housing runs at about 10-11 PSI when the solar panels are not being used. When water is flowing through the solar panels that pressure gauge reads about 19 PSI. Will I have a problem with the SWG with those pressures and if so how do I solve it?

 

[Jimrahbe]

D,

I would not worry about it.. They are talking about a differential pressure between the input to the cell and the output of the cell.

Since one side of the cell is basically the pool, you will not see anything close to 10 lbs.

The reason your filter pressure is 10 lbs, is because it takes effort to push the water through the filter.. It takes very little effort to push the water through a salt cell..

Thanks,

Jim R.

 

[setsailsoon]

D,

I have the exact same unit installed. Been in service for a year with filter pressures up to 22 psi. I'm sure Jim is correct about the pressure. Notice on the same warning they tell you not to block flow downstream. This would increase pressure above 10 psi in most systems. It's never a good idea to block your pump discharge flow even with no swg.

I hope this helps.

Chriis

 

[dswwpb]

Thanks guys, that makes me feel better about the psi. Chris you mentioned blocking flow downstream of the cell. I have 1 1/2 " return lines underground but 2" coming off the filter housing. I can neck down to 1 1/2 " piping before the cell or after. If I neck down to 1 1/2 after the cell would that be considered blocking the flow?

 

[Jimrahbe]

D,

It will make no difference at all..

Blocking the flow is when you shut off a valve and the water has no place to go.. Just go install your SWCG and enjoy your saltwater pool..

You will love it.

Thanks,

Jim R.

 

[JamesW]

The only situation where the pressure in a cell would be higher than 10 psi is if you have an in-floor cleaning system.

Other than that, the pressure should not be able to get to 10 psi.

Note that the filter pressure is before the filter and solar and the cell is after all other equipment. So, the filter pressure is not going to be the pressure in the cell.

 

[dswwpb]

Thank you

 

[setsailsoon]

Thanks guys, that makes me feel better about the psi. Chris you mentioned blocking flow downstream of the cell. I have 1 1/2 " return lines underground but 2" coming off the filter housing. I can neck down to 1 1/2 " piping before the cell or after. If I neck down to 1 1/2 after the cell would that be considered blocking the flow?

D,
It's best to do the reduction in pipe diameter after the cell. But if you've already installed I'm sure it will work. As I recall there are two sets of flange parts that allow you to use 2" or 11/2" pipe. When I said block flow I was really referring to closing a valve. Severe restriction like almost closed is not good but the difference in pressure drop for 1 1/2" pipe is minimal for normal design flow rates.

Be sure to raise your CYA to TFP recommended levels. I was so used to much lower CYA I was reluctant to do this and saw pretty high FC demand. Raising it made a huge improvement. I also added borate shortly afte.r swg. PH is much more stable. For some reason pH stability improved over time. Now I'm using way less acid and keeping my pH higher in the range.
.

I hope this helps.

 

[dswwpb]

D,
It's best to do the reduction in pipe diameter after the cell. But if you've already installed I'm sure it will work. As I recall there are two sets of flange parts that allow you to use 2" or 11/2" pipe. When I said block flow I was really referring to closing a valve. Severe restriction like almost closed is not good but the difference in pressure drop for 1 1/2" pipe is minimal for normal design flow rates.

Be sure to raise your CYA to TFP recommended levels. I was so used to much lower CYA I was reluctant to do this and saw pretty high FC demand. Raising it made a huge improvement. I also added borate shortly afte.r swg. PH is much more stable. For some reason pH stability improved over time. Now I'm using way less acid and keeping my pH higher in the range.
.

I hope this helps.

It looks like it will be easier to reduce down after the cell so that's the route I'll probably take. My CYA was WAY high after using tabs for so long, so I drained about 4700 gallons and got it down to 70 which is what's recommended. My PH is 7.6 but TA is 100 which hopefully goes down a bit with the SWG. Do you think your pool PH stablizing and using less acid is due to the borate?

 

[JamesW]

The 10 psi warning seems to be new.

I'm not aware of any other cells specifying such a low limit.

Maybe they had a significant number of cell failures that they attributed to excessive pressure?

Maybe they had failures due to hydrogen gas and chlorine gas buildup and they attributed the failures to excessive pressure.

Any pool equipment should be certified to at least 30 psi, in my opinion.

A 10 psi limit seems to indicate that the cell isn't made very well and that they are not confident in the cell being able to handle regular pool pressure.

They need to put the cell limit in their sales literature and to say that their system is not suitable for pools with in-floor cleaning systems.

 

[setsailsoon]

The 10 psi warning seems to be new.

I'm not aware of any other cells specifying such a low limit.

Maybe they had a significant number of cell failures that they attributed to excessive pressure?

Maybe they had failures due to hydrogen gas and chlorine gas buildup and they attributed the failures to excessive pressure.

Any pool equipment should be certified to at least 30 psi, in my opinion.

A 10 psi limit seems to indicate that the cell isn't made very well and that they are not confident in the cell being able to handle regular pool pressure.

They need to put the cell limit in their sales literature and to say that their system is not suitable for pools with in-floor cleaning systems.

Good points you make James. I would guess it's a combination of things but just looking at how the cell housing is manufactured plus the sealing surfaces I'd bet it would go well above 10 psi. They have an exceptional warranty and a pretty good reputation here so I'm guessing it is something ridiculous like liability. Their customer support has been fantastic to work with so I may give them a call about this and see what they say.

Chris