Does a SWG require a certain amount of GPM flow to generate chlorine?

[ValTag]

I have a dual speed pool pump and in order for my hayward heater to work the pump needs to be on high speed. The low speed does not have enough GPM going through and the heater won't turn on.
Is it the same with a SWG? Does it take a certain amount of pressure to generate chlorine from the salt? Can i run my pump on low speed all day if using salt? Thanks
10,000 gal ig vinyl pool 2" plumbing DE filter

 

[JJ_Tex]

Yes, most/all SWGs have a flow sensor that requires a certain amount of flow to generate chlorine.

Mine has a light on it that will tell you if the flow is good or not. What type of SWG do you have?

 

[Jimrahbe]

Val,

A 2-speed pump on low will close the SWCG flow switch on most pools..

That said, the only why to know for sure is to try it.

Thanks,

Jim R.

 

[ajw22]

Heaters use a pressure switch while SWGs use a flow switch.

A gas heater typically requires 20-40 GPM to trigger the pressure switch.

A SWG flow switch will trigger with around 12 GPM of flow.

What heater and SWG are we discussing?

 

[gkw4815]

Every system behaves differently.

FWIW, I typically run my 3 hp VS pump with a low speed of 1300 rpm. This is not enough to run the heater.

When I installed my SWG, I deliberately delayed a long-overdue cleaning of my cartridge filters to see if 1300 rpm would still be sufficient to close the SWG flow switch with dirty cartridges. In my case it was.

 

[Stefaniems]

Heaters use a pressure switch while SWGs use a flow switch.

A gas heater typically requires 20-40 GPM to trigger the pressure switch.

A SWG flow switch will trigger with around 12 GPM of flow.

What heater and SWG are we discussing?

 

[Stefaniems]

Yes, most/all SWGs have a flow sensor that requires a certain amount of flow to generate chlorine.

Mine has a light on it that will tell you if the flow is good or not. What type of SWG do you have?

I'll double check that, but in the past it has not been a problem. Thank you.

 

[ValTag]

Thank you for the info. I currently do not have a SWG but there's always someone trying to talk me into converting for 2 reasons...water feel and cost savings.
I have a TriStar 2 speed 1 hp pump that is rated 1.85 hp. Once my pool is up and running i generally run the system on low speed...so maybe .25 hp? Whenever we need to use the Hayward gas heater I have to run the pump on high speed in order for it work. We do use the heater often (spillover spa) but not daily. I suspected that a SWG might require a certain amount of pressure. If so then all the money I save using the low speed would be lost....liquid bleach is fine on low... I would just stick with what I have

 

[ValTag]

Val,

A 2-speed pump on low will close the SWCG flow switch on most pools..

That said, the only why to know for sure is to try it.

Thanks,

Jim R.

Thank you. I don't have one to try. If it's likely that I won't be able to run it on the low speed then I wouldn't consider converting to one.

 

[ValTag]

Thank you...it's a Hayward gas heater I think 250btu..don't remember...but it only works on the high speed. It has even shut down when we were overdue for a backwash so it's pretty sensitive about the flow. The low speed is super quiet and has a very low flow so I don't think it would be enough. In fact I was thinking thT maybe the flow/pressure is even low because all the piping is 2 inches wide instead of 1½ inch
Just wondering...thanks