The below diagram is from http://www.poolcenter.com/plumbingSchematics and is described as follows:

Basic Pool & Spa Combination Plumbing Diagram

  • 4 Jandy 3 way valves
  • 1 Jandy 2 way valve
  • 1 Jandy Check valve
  • 2 Jandy Valve Actuators

Common pool plumbing layout for the pool/ spa combo design with shared pool & spa heater and controller.

My question is:

What is the purpose of the horizontal connection from the Spa Return to the Pool Return via the 3 way valve?

There is already a route via the Spa Make-up and Check Valve to the return.

If you wanted to configure the system to pump to "spa only"... you'd want everything going through the Check Valve, right?

You wouldn't want leakage to the Pool Return, and you wouldn't want water going past the check valve?

enter image description here


My understanding, which is very limited, is that this setup would be for a Spa that's physically higher or at least fills higher than the pool. The actuator valve would only keep both bodies at a level height & equally heated.

But, with the actuator valve's Spa return closed, only then can the Spa overfill & even up to an overspill. Also, this setup would then allow for the Spa to be overheated or heated above the pool's temperature.

  • There are 4 3-ways. It's confusing because they are covered by actuator symbols. So the actuators are on 3-ways, and the 2-way is the spa make-up. That makes total sense now with overflow/overheating. My spa is actually connected to my pool via a little channel on the spa wall, and both are the same water level. I'm wondering if I should do the same type of plumbing.
    – Vigrond
    Mar 11 '16 at 17:52
  • Oh you're right, thank you. I should've taken another couple of looks, I'll remove my mistake from the answer. Yeah, I'm not sure how they see this as "Basic" when it's quite specific...most setups I've seen are like yours. You should be able to do it, but if you have a Spa skimmer, which this does not, then you'll have to plug & seal that off as needed or permanently & go to over-spilling into the pool for those skimmers.
    – Iggy
    Mar 12 '16 at 3:20

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