Spa heating

[Cleavitt]

I have recently moved into a home with an inground pool and spill over spa. A heat pump is attached to the system to heat the spa and/or pool. I haven't really played with the spa too much yet, but I have fired it up a few times and it took about an hour to raise the spa temp 5 degrees. When the system is in spa mode the heat pump comes on and the valve actuators isolate the spa from the pool plumbing as expected. The owners manual for the heat pump states that it is best to leave the spa air bubbles off when attempting to heat the pool because it can slow the heating process significantly. The problem is, I have no idea where the spa bubbles are coming from or how to stop them. There is an air intake (i think) pipe coming out of the ground near the spa, but I don't see any valves or devices that might be part of the "air injection" process.

Is there some sort of voodoo at work here? How is the air injection typically accomplished on a setup like this and what is the best way to temporarily disable it?

 

[Cleavitt]

Nevermind, I figured it out. It seems the "air injection" is as simple as having an air intake pipe plumbed into the spa returns. Or at least that is the way it appears. I covered up the air intake pipe and the bubbles stopped and I didn't hear the sound of something about to explode/implode. I can't really wrap my head around why that air intake draws in air instead of water blowing out of it, but that is probably none of my business anyway. :lol:

 

[lborne]

I can't really wrap my head around why that air intake draws in air instead of water blowing out of it, but that is probably none of my business anyway. :lol:

http://en.wikipedia.org/wiki/Venturi_effect