Equipment pad layout question

[madgunner]

I'm looking for a review of this proposed pool equipment layout. Prefer to have two pumps, ensuring we can enjoy the water features in the pool while the spa is running.

The first layout shows two pumps with three possible operating modes, with actuators that would flip the 2-port valve open/close, and the 3-port valves either to the left or right. Three valves with actuators. Pump #1 runs the spa. Pump #2 runs the pool circulation and water features. The pipes to and from the pool are 2-inch. Three modes = spa mode, spa mode with features, pool mode. This design leverages the same filter, heater and SWG to support the spa in the first two modes, and to support the pool in the third mode.

Option 1:

Option one has three modes, but two operating positions:

In the first mode, the actuators toggle into spa mode / spa position. In spa mode, only pump #1 runs, and water flows from the spa drains through the pump to the filter, heater, SWG, then to the spa jets.

The second mode, spa+features, pump #2 is turned on (actuators remain in spa mode position). When pump #2 is turned on, a second water flow is started that pulls from the pool drains and skimmers, passes through pump #2 and circulates back to the pool and water features, bypassing the filter/heater/SWG.

In the third mode, the actuators toggle into pool mode / pool position. In pool mode, pump #1 is turned off. Pump #2 is turned on, and water flows from the pool drains and skimmer, through pump #2, then through the filter, heater, SWG, then back to the pool and water features. This would be the mode used for 8~12 hours per day to circulate the water, generate chlorine, etc.

Pump #1 - driving the spa jets - is a 2-speed Hayward TriStar.
Pump #2 - driving pool and features - is a variable speed Hayward EcoStar.

If the PB can program the controls, it would be interesting to have spa mode run the TriStar at low speed, and in spa+features have the TriStar run at full speed, with the EcoStar running at whatever speed generates a nice effect with the bubbler on the tanning ledge and the two sheers. The pool mode option should remain the default setting for the system, with the EcoStar run on a timer using a low, energy-saving setting for part of the time, and a higher rate to ensure the skimmer and SWG receive sufficient flow for optimal operation several hours per day.

--/--

The second layout was the original PB design, which uses a single pump and has a spa mode and a pool mode. When in spa mode, the pool circulation stops and water features stop. When in pool mode, the spa jets stop.

Option 2:

I'm very much interested in comments from other pool builders or owners that have similar configurations. Is the first option too complex?

What am I missing? Any alternatives that will accomplish the same goals (two pumps, shared filter and heater)?

Bonus question - would it help to ensure all pipes between equipment use 2.5" PVC - or use 2" pipes since the pool pipes are 2" (and 1.5") ?

Thanks!

 

[JasonLion]

Your first diagram has a serious problem that render it unusable, as well as some un-needed confusion. The most serious problem is that you can't plumb two pumps in parallel like that unless they are matched/identical. Whichever pump is stronger will simply shut the other pump down and cause it to overheat. That can't happen in all combinations of valve settings, but you should never risk the possibility of it happening in the first place. Also, the way you have the heater/filter bypass setup will lead to problems eventually. You have two three way valves that need to be synchronized to each other, which is unlikely to always be the case. Finally, that combination will be difficult to automate. You want valves that serve a single simple purpose for automation, not complex combinations of valves that need to be turned in ways that are consistent with each other.

A two pump pool/spa setup always has the pumps on separate plumbing loops. That makes controlling the setup far simpler and eliminates any risk of valve mis-adjustment at the cost of having two sets of floor drains in the spa (one for each pump).

The second diagram is better, but I don't like the spa floor return not being separately adjustable. I would simply eliminate it, but you could alternatively provide a valve to limit the flow rate for constant spa spillover.

This page has a collection of classic equipment pad layouts. Whatever you do would be well advised be based fairly closely on one of these.

 

[madgunner]

Thanks for the link to Pool Center schematics page.

This diagram from the Pool Center schematics page has a lot in common with option 1 in this thread, as there are two pumps, shared heater, with multiple check valves preventing the two pumps from conflict. What about option 1 won't work, compared to this alternate design?

 

[JasonLion]

Not my favorite one of their diagrams.

This setup has the same potential problem as yours, though getting into that situation is a little less likely than it was in your diagram. You don't get into trouble with this diagram unless both pumps are sending water to the heater. If you did set it that way (both to heater) the pumps either need to be matched, or one of them will overheat.

 

[madgunner]

Updated layout shown in the below diagram. As with the shared heater layout from Pool Center, this layout could be trouble in a scenario where an actuator fails, but I don't see the risk as any higher in this layout versus the Pool Center layout. If this layout is still "best not to do" please recommend an alternative. The gunite and pipes to the pool are already set, so there's not much option to change the inputs/outputs at this point, but we can change everything on the pad layout.

Four check-valves to protect / direct water flow, same as with the Pool Center layout. The additional two check-valves shown in the upper right are for the spa, which may sit slightly higher than the equipment pad (e.g. these aren't part of the solution for sharing equipment).

Two actuators for 3-port valves (left/right flow control) are required in this layout, where the third actuator, a 2-port valve (open/close) is optional. The Pool Center layout uses three actuators, all of which are 3-port valves.

There are valves on each of the inputs and outputs to/from the pool and spa, which allows the returns to be controlled (e.g. control the floor return to the spa so the spillover in pool mode can be tweaked, or control the bubbler return to the pool to increase or reduce the height of the stream).

From an automation perspective:
Spa Mode - set both 3-port actuators to right, and set the 2-port actuator to close; turn on pump 1, turn off pump 2
Spa+Features mode is the same as spa mode for the actuators, the only change is that pump 2 is turned on
Pool Mode - set both 3-port actuators to left, and set the 2-port actuator to open; turn off pump 1

This is all new from my perspective, so the feedback is greatly appreciated! Thanks.