OK, some brief background.
I just moved into a new house and am now the first time onwer of a pool/spa. I've been reading up the last couple months and trying to learn as much about my setup as possible (I'm more of a DIY person...I always modify, tweak everything I own..it's a bit of a sickness ) Anyway, I just made my first mistake...completely my fault for not researching and learning enough. But, here's what happened:
My spa is above the pool and has the water cascade over one edge into the pool. I have a two pump system, cartridge filter, heater. The spa has 2 main drains, a number of jets. The pool has a main drain and a skimmer. This setup is from somehwere in the early 90's (my guess). The two pumps are identical 2HP Pentair Ultraflow pumps. One pump is for the pool and one is for the spa. Well, I think a better description is one is for the pool and the other is a booster pump for the spa. That's sort of where my mistake comes in.
The 'main' pump for the pool has three suction lines coming in. One from the skimmer, one from the main drain (each with valves to open/close) and a third pipe without a valve. I wasn't sure about this one, but I thought this might be the inlet from the pressure return of the booster pump? All three of these pipes join to a three way jandy valve before going into the inlet of the main pump.
The second pump (booster pump) has one suction line coming in with a valve. I'm nearly certain this is simply coming from the main drain from the spa, since the water will flow from the pump basket continoulsy if I have the cover off and the valve open (since the spa is higher than the pump). The pressure return from this booster pump goes into the ground to I 'assume' that third inlet to the suction side of the main pump.
Here's where my mistake today came in: I have been filtering and vacuuming the pool for the last few weeks/months, getting used to the setup and beginning to check my water chemistry, etc. The water flows back to the spa and pool, overflowing from the spa. This is all from the main pump. The booster pump had never been turned on before today. I wanted to see how that pump operates and the effect on the spa, etc, and to get a better undertanding of the system. Well, that jandy valve that I mentioned above didn't have a handle on it, so I never even thought it through that it may be closed coming from the pressure side of the booster pump. I almost thought it purposely didn't have a handle so you don't mess with it. The breakers on the main and booster pump are keyed so that the main pump has to be on first (seeming to reassure that the third line into the main pump is the pressure return from the booster pump).
Immediately upon turning on the booster pump, the pressure built up too high and cracked the housing (part # v38-130). I immediately turned the booster pump off, closed the suction valve, and the water stopped spraying/leaking out. Then, I decided to troubleshoot.
Turns out that jandy valve without the handle had that third line closed. If I'm right and that is indeed the pressure return from the booster pump, that pressure had no where to go until it broke something. It was my mistake for not checking it, but seeing that there was no handle on it, that is probably why I overlooked it (and me being green to the whole new setup didn't help). Well, lesson learned.
I see that there is another jandy valve on the return from the heater exit...assuming you can direct where you want most the returned water to go (pool or spa). Well, I took that handle off (didn't know they even came off that easy) and put it on the jandy valve in question. Of course...it was closed to that third inlet to the main pump. So, I'm 99% sure that is what caused my problem and the booster pump housing to crack. Completely my fault and I can admit that it was my mistake for not checking better.
OK, time for my options: The good news is that I don't even plan on using the spa as a spa. I don't feel like paying high gas bills to have a spa that I will probably never use or grow out of very quickly. The pool, on the other hand, I will use a lot. So, that being said, I'm in good working order even with the broken booster pump. My spa will simply act like an extension of the pool. The main pump is still filtering the pool/spa and running the skimmer/vacuum.
My question comes into whether I should even replace the broken part or to go to a single variable speed pump system?? Since these are pretty old pumps in the first place, I'm not sure if it would be wise to invest more money in them. Doing a quick search on the replacement volute, the part is about $90 shipped at the cheapest find and then complete disassembly is needed to replace it.
I was looking at the new Intelliflo variable speed pumps. Not only would it save me probably 70% on electricity costs, but I could run my pump longer each day and use it at the higher speed if I ever did want to use the spa. Would that be a viable option for me? Can one variable speed pump replace my two pump system? Or is that just a bad choice for some reason? I was just telling my wife that I was thinking about replacing our main pump with a variable speed to save costs...maybe this booster pump breaking was a sign for me to go that route.
If anyone can save me a little time and research, it's much appreciated. I like learning myself, but others more experienced can always speed up the process and help avoid common issues. Sorry for the long post.
The pool size is roughly 20,000-25,000 gallons. I can give any additional info that is needed.