What is installed prior to SWG?

[Swordfish]

I'm sorry if this is common knowledge, but what is this inline device that is installed just prior to a SWG?

The pic is terrible, I was hoping to get the model number to figure it out myself. Is it something for backpressure?

 

[JasonLion]

That is probably a check valve, which are only occasionally installed before SWGs. It might instead be a flow switch, but they don't generally look quite like that. Those are the only two things that would have a flow arrow.

 

[Swordfish]

Thanks! I think there is a flow switch ahead of this item, but before the swg. So why would a check valve would be installed here? The equipment is about even with the pool deck.

 

[JasonLion]

Check valves are sometimes used in this location to prevent water high in chlorine from flowing back towards the heater. Check valves are much more commonly used with tablet feeders, which perform a similar function as a SWG but involve much higher chlorine concentrations. They aren't usually needed with a SWG, though if the SWG is too close to the heater a check valve might be a good idea.

 

[Swordfish]

That probably explains it then. There is a heat pump nearby. Thanks for the info.

Sent from my SCH-I545 using Tapatalk