Check my plumbing design?

[chatcher]

Last year I started a DIY vinyl 20x40 kidney-shaped pool project and got as far as setting the wall panels. For a variety of personal reasons I stopped work on it and left it sit for a year. I've finally gotten back to it now, and after re-doing a lot of the excavation due to winter wall cave-ins and spring erosion I'm finally back where I left off and ready for concrete and after that, plumbing.

My pool will be 25,500 gallons with a Triac spillover spa. I have a Goldline Autologic PS-8 controller with chlorine cell, and a Northstar 2hp max-rated 2-speed pump and 500-lb sand filter. I'm now on my tenth or so revision of plumbing design. I started with the Goldline drawing and deleted the things I don't have and reworked a few details. Some of the choices I made may seem a little odd, so I should explain my reasoning. First, the PS-8 controller has a lot more switching relays than valve outputs. This causes me to in some cases lean toward adding pumps to automate features that I otherwise might have chosen to use valves for. I wanted remote control for the deck jets. By putting them on a separate pump connected to an unused relay I avoided using another valve output, plus I gained the ability to run them while using the spa. Another pump is used for the spa jets, which I think I could have run from the filter pump (on high speed), but it would have cost another valve output since I didn;t want the jets on all the time the spa was selected, for instance while heating prior to use. The reason for putting the vacuum port on an automatic valve was to add the ability to schedule running a Navigator pool cleaner during times the pool is not in use. For the solar heater I may not need a booster pump and will try runninng without one first. Alternatively maybe I could have skipped the solar valve and used just the booster pump control to turn solar heating on and off. I'm willing to re-visit all these choices if there is a better way to go.

What I'd like now is to get opinions on the design before I install it, while there is time for easy corrrection or improvement. I'd appreciate any comments you might have.

 

[mas985]

First, given that you have a separate pump for the spa, I don't think you need a 2HP filter pump. 3/4 HP will probably do you just fine unless there is another reason you needed more.

Second, I doubt you will need the solar booster pump even if you down size to a 3/4 HP pump unless the solar panels will be mounted on a roof higher than 60 feet.

All long lengths of run, I would use at least 2" plumbing. Remember, head loss decrease by the 5th power of pipe diameter. So a small change in pipe diameter is a very large change in head loss. Also, 2 1/2" on the pad is not that much more money but can really pay off in efficiency since there are usually a lot of bends.

For suction lines, the minimum should be 2" even if you have parallel lines. On the return side, since you have 3 returns, you could get away with 1 1/2" but I would go with 2" lines. On the spa, a 2" is minium since you only have one line. Spa Jets, I would use all 2 1/2" lines unless the pump is right next to the spa, then 2" would be ok. What size spa jet pump were you planning and it looks like three jets?

Also, I would up the size of the plumbing for the deck jets if you are looking for flow. If they are high pressure jets, it doesn't matter as much but I would use 2" as a minium. What size is that pump?

I would put check valve for spa on the spa side plumbing instead of where you have it on the suction side. This will reduce head when in circulation mode.

As for relays, I think that the PS-16 doubles the number of relays so you might want to consider that.

 

[chatcher]

First, given that you have a separate pump for the spa, I don't think you need a 2HP filter pump. 3/4 HP will probably do you just fine unless there is another reason you needed more.

Yes, I think I oversized the pump, but now I own it... Originally I thought I needed the 1 1/2 HP (so-called 2HP Max)because of the spa jets, and planned to run on low speed most of the time. If the pump did not have a low speed, I'd definitely be trying to trade down, but I think the low speed will work well for most of my purposes.

Second, I doubt you will need the solar booster pump even if you down size to a 3/4 HP pump unless the solar panels will be mounted on a roof higher than 60 feet.

The panels will be less than 20 feet higher than the water surface, so that sounds good to me.

All long lengths of run, I would use at least 2" plumbing. Remember, head loss decrease by the 5th power of pipe diameter. So a small change in pipe diameter is a very large change in head loss. Also, 2 1/2" on the pad is not that much more money but can really pay off in efficiency since there are usually a lot of bends.

I'll look into 2" minimum and 2 1/2 on the pad, at least for the suction side. I had planned to run one 2" line for both skimmers and tie into the 1 1/2" port on each, with the idea of balancing flow. I could run a separate 2" to each skimmer and tie together on the pad. I'm less worried about head loss on the return side since it will reduce flow rate (and pumping HP and amps).

For suction lines, the minimum should be 2" even if you have parallel lines. On the return side, since you have 3 returns, you could get away with 1 1/2" but I would go with 2" lines. On the spa, a 2" is minium since you only have one line. Spa Jets, I would use all 2 1/2" lines unless the pump is right next to the spa, then 2" would be ok. What size spa jet pump were you planning and it looks like three jets?

The spa was pre-plumbed with two 2" suction lines (two drains on each), one 1.5" return line to a single return jet, and one 2" return line split among six spa jets which can each be adjusted from full off to full on. I added two more spa jets on a separate 1.5" line. Spa jet pump, if I use one, hasn't been spec'd yet. I do have some whirlpool bath pumps (supposedly 1 1/2 HP, but really 115-volt, 9.5 amp) which might work if I can keep them primed. Spa is pretty close to the pad.

Also, I would up the size of the plumbing for the deck jets if you are looking for flow. If they are high pressure jets, it doesn't matter as much but I would use 2" as a minium. What size is that pump?

Deck jets (four each) are rated 5 GPM each at 11 ft head, so 20 GPM total didn't sound like a lot of flow to me. Pump hasn't been chosen, again I may try one of the whirlpool bath pumps. I hate to use a pump for them, but can't think of any other way to run them while using the spa. I don't want to spray away the heated spa water!

I would put check valve for spa on the spa side plumbing instead of where you have it on the suction side. This will reduce head when in circulation mode.

If I put the suction side check-valve on the spa side of the pool/spa suction valve, the direction of flow will have to be away from the spa, which won't prevent the spa draining into the pool when the pool/spa valve is turning. Or do I misunderstand?

As for relays, I think that the PS-16 doubles the number of relays so you might want to consider that.

It's too late for a PS-16 now! Looking back on my choices there are a few things I would definitely change, but even if it means I have to manually turn a valve to vacuum (yikes), I have to live with the four valve limit of the PS-8. If I use the fourth valve to run the spa jets off the main pump, I could get by without an extra pump. Or maybe I could look for an electric solenoid valve for the vacuum.

Thanks for taking the time to help me - I appreciate your advice.

 

[mas985]

Ignore the comment on the check valve, you are right and I wasn't thinking.

On the suction side, it is a very good idea to run separate lines to each skimmer and main drain pair so that you can adjust the suction from each. You can then isolate the main drain if you ever need to do a refill.

Also, on the spa, even though the lines are short, you have only one return so I would go with a minimum of 2" line. The suction is probably ok since you have two 2" lines otherwise I would go with one 2 1/2".

BOTH suction and return head loss will reduce flow rates and cost more in energy $$ so it is a good idea to have larger lines. If they are already in the ground then I wouldn't worry about it.

For the deck jets those are recommended flow rates and not what you may actually get. Your flow rate will depend on the pump and your plumbing. No matter what pump you choose, it will probably be well above 20 GPM. You could run them off the same filter pump since the SPA has a separate pump for the jets. You will not be able to run the deck jets while the spa heats but after that, you could then run the deck jets since the spa jets have their own pump.

I believe, you can convert a PS-8 to a PS-16 with the expansion unit so you may still be able to go with that.

 

[Titanium]

chatcher,

First, the PS-8 controller has a lot more switching relays than valve outputs. This causes me to in some cases lean toward adding pumps to automate features that I otherwise might have chosen to use valves for.

I would think that you could use the relays to operate valves. Rather than having the relays switch 240 Volt power, you would have the relays switch 24 Volts AC to the valve actuators.

I believe, you can convert a PS-8 to a PS-16 with the expansion unit so you may still be able to go with that.

You can do this, but you would need to buy both the expansion unit and the PS-16 local display. The main circuit board in the AquaLogic line is identical for the PS-4, PS-8 and PS-16. The local display being a PS-4. PS-8 or PS-16 display is how the main circuit board knows which functions to activate. And the local displays are fairly expensive.

Titanium

 

[chatcher]

I would think that you could use the relays to operate valves. Rather than having the relays switch 240 Volt power, you would have the relays switch 24 Volts AC to the valve actuators.

That's an interesting idea I'll have to try. If I can make it work I could use it on a valve that doesn't need the logic that turns off the pump while the valve rotates. I might have to add a separate relay because I think the actuator requires 24vac between one wire and common to open, and between a different wire and common to shut. I might even be able to steal the required 24vac from the Aqualogic. It must be in there somewhere for the other valves.

I believe, you can convert a PS-8 to a PS-16 with the expansion unit so you may still be able to go with that.

You can do this, but you would need to buy both the expansion unit and the PS-16 local display. The main circuit board in the AquaLogic line is identical for the PS-4, PS-8 and PS-16. The local display being a PS-4. PS-8 or PS-16 display is how the main circuit board knows which functions to activate. And the local displays are fairly expensive.

It's interesting to learn an upgrade is possible, even though I'm pretty sure it would be cost prohibitive for me, considering what I would gain from it.

 

[chatcher]

First, given that you have a separate pump for the spa, I don't think you need a 2HP filter pump. 3/4 HP will probably do you just fine unless there is another reason you needed more.

After further consideration and some makeshift testing of the spa using the 2HP filter pump and a separate whirlpool pump, I bit the bullet and bought a 3/4 HP filter pump. I think it will work for everything I have, without using any booster pumps. The design is getting simpler and simpler. I'll use a remote 3-way valve to turn on the spa jets, and will live with no pool deck jets when the spa is in use. There's a good chance they would not have been all that entertaining, anyway.

I do have a question on the use of a Vac-Lock fitting for the suction side cleaner. Is it possible to open the cover with suction applied, or do you have to turn it off before opening? In hand it is pretty hard to open, and I'm guessing adding suction will make it even more so. I assume for safety reasons it is supposed to be difficult (childproof?). Since I won't have an extra valve circuit in my Aqua Logic to control the vacuum port, I have decided to use a manual valve instead.