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Thread: What is "Too Hot?"

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    What is "Too Hot?"

    I will be installing my Aquarite this weekend and I've read the manual cover to cover. The manufacturer recommends the SWG cell be the last thing the water touches before returning to the pool. While this poses some plumbing challenges for me in my setup, I can do that. However, the manual also says that the cell will not function if the water temperature is too high. They don't specify what "too high" is, but there are occasions where the water returning to my pool is over 100 degrees. I've actually had it north of 140 for several minutes when the solar kicks in on a hot day and the water has been trapped in the panels, but this is really rare and only lasts a few minutes.

    In the summer, typical return water temperature is around 92-95 degrees in the mid-afternoon. Will this be too hot for the SWG? Is there any problem plumbing the cell in before the solar valve? When I asked Hayward Pools about plumbing it in before that valve (I didn't ask about the temperature), they said, "We recommend it be the last device in the flow." When I asked why or if there'd be problems putting it before the solar, he simply repeated the exact same sentence verbatim.
    blubluenoiseise

    My pool: 14,750 gallons in-ground plaster
    FAFCO Solar panels (seven 4' x 12') with a Goldline automatic controller
    1/2 HP WhisperFlo filter pump, Kreepy Krauly cleaner, Cartridge Filter
    Aquarite SWG, Satisfied user of the TF-100 Test Kit

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    Its not that there will be any catastrophic problems with hot temps, but that it may shut down briefly. How hot is hot? Commercial guidelines for spas says that it should not exceed 104 degrees, so for all practical purposes, greater than 104 is too hot.
    I would be cautious with 140 degree solar panel temperatures as that may cause OTHER components to fail. That's quite hot!

    Regarding placing the cell before the solar panels, I would not suggest that either as the concentrated chlorine levels that can eminate from the cell can cause problems with degradation in the solar panels. Especially if the concentrated chlorinated water is trapped in the solar panels with the pump shut down.
    Please plumb it afterwards.
    Sean Assam - Sean@teamhorner.com
    National Accounts and Commercial Products Manager
    AquaCal Heat Pumps www.aquacal.com
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    Sean...what happens with Solar Panels down south when the sun is at its hottest...I can only imagine the trapped water in there easily getting near boiling?

    Rik

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    mas985's Avatar
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    Quote Originally Posted by pooladdict
    Sean...what happens with Solar Panels down south when the sun is at its hottest...I can only imagine the trapped water in there easily getting near boiling?

    Rik
    If installed properly, the panels should automatically drain when the pump shuts off.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    mas985's Avatar
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    Re: What is "Too Hot?"

    Quote Originally Posted by bluenoise
    I will be installing my Aquarite this weekend and I've read the manual cover to cover. The manufacturer recommends the SWG cell be the last thing the water touches before returning to the pool. While this poses some plumbing challenges for me in my setup, I can do that. However, the manual also says that the cell will not function if the water temperature is too high. They don't specify what "too high" is, but there are occasions where the water returning to my pool is over 100 degrees. I've actually had it north of 140 for several minutes when the solar kicks in on a hot day and the water has been trapped in the panels, but this is really rare and only lasts a few minutes.

    In the summer, typical return water temperature is around 92-95 degrees in the mid-afternoon. Will this be too hot for the SWG? Is there any problem plumbing the cell in before the solar valve? When I asked Hayward Pools about plumbing it in before that valve (I didn't ask about the temperature), they said, "We recommend it be the last device in the flow." When I asked why or if there'd be problems putting it before the solar, he simply repeated the exact same sentence verbatim.
    I have the Aqualogic which is fairly similar to the Aquarite product. Sometimes when the solar turns on and the water is above 105 degrees, the current gets too high in the cell and it shuts down for the remaining part of the cylcle. It will then start up automatically the next cycle. A solar bypass pipe can help some by mixing the hot water with colder water but you need to make sure you can adjust the flows properly to make it work. Also, the Aqualogic has a 60 second delay when the pump is first turned on which helps with the problem some. If solar turns on after the pump, then that is usually when the problem can occur but not always.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    I am not so sure on thoroughly draining, I even have a solar controller equipped set, and one temp probe is inserted through a hole in the panels, it needs water in there to be working properly no?

    I always have some water in mine, was just curious about what could happen if left on for a full day of sun?

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    Quote Originally Posted by pooladdict
    I am not so sure on thoroughly draining, I even have a solar controller equipped set, and one temp probe is inserted through a hole in the panels, it needs water in there to be working properly no?
    Normally the solar temperature probe is installed on top of the panels and not actually in the pipe or panel. I don't think the panels would work properly if the temp probe was installed inside the panel. Once the panel turned on, the temp probe would see a drop in temperature due to the colder water of the pool and then the controller would turn off the panels.

    If the probe is installed on top of the panels, it will read the same temp if water is flowing throught the panel or not. It is the incident energy of the sun directly on the probe which should turn the panels on and off and not the water in the panel.

    Quote Originally Posted by pooladdict
    II always have some water in mine, was just curious about what could happen if left on for a full day of sun?
    Sometimes when my solar turns off the panels will not drain completely until the pump is off. The pressure keeps them partially filled. So short answer is that there probably won't be any damage to the panels. However, if you get freeze, you may have damage.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Thanks Mark, I know my panels stay filled when the pump is on due to that darn return line, I guess I could get a one way valve on there so no water is incidentally pushed up the return when its turned off.

    My controller is plumbed in between the two panels, so it catches the proper temp and they are working great.

    Thanks again for telling me your panels remain full when ur pump is on.

    Rik

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    The water on my system is valved at the "send" end of the solar panels. In other words, when the controller asks for heat, the valve opens to send the water to the panels. The return from the panels is then Tee'd into the return that comes from the remaining "unheated" port on the multiport valve. Even if the valve is set to not send water to the panels, they get filled with water and held by the return pressure. It sounds like Rik's is the same way. When the pump shuts off, lots of water pours down and out the return. On a hot day, that water can scald if you're near a return jet. In fact, the water looks like heat ripples as it blasts into the pool like an underwater geothermal vent.

    The challenge I'll face when installing the SWG is that the Tee that joins the solar return to the pump return is underground and about 4-5 feet from the equipment pad. Presumably, I'll need to dig down to the return pipe and bring it above-ground for the cell installation. It won't be pretty. I'm going to have to see if I can rework the plumbing on the pad to allow me to bring that Tee closer to the rest of the equipment.
    blubluenoiseise

    My pool: 14,750 gallons in-ground plaster
    FAFCO Solar panels (seven 4' x 12') with a Goldline automatic controller
    1/2 HP WhisperFlo filter pump, Kreepy Krauly cleaner, Cartridge Filter
    Aquarite SWG, Satisfied user of the TF-100 Test Kit

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    Hi Bluenoise:

    I have my aquarite plumbed in so its the last thing before returning to the pool.

    Here is how it is done. I was told to do it this way, for a couple of reasons.

    I put all those Ball Valves in so I can remove the Cell at anytime and still be able to run the pool normally. I think my problem from backloading from the solar return is due to not having such a thing as a one way valve. I wasnt sure one of those was available.

    Hope this helps,

    Rik
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    Thanks, Rik. That looks like the type of setup I'll be doing, too. I hadn't thought about the ability to bypass the SWG like you've done, so I'll have to see if that's an option for me. I like the idea of being able to service the cell without shutting the thing down, especially if I need to remove the cell for an extended period of time. I have seen "dummy cells" that go in place of the real cell, so I suppose one of those could be a decent "plan B."

    One-way valves (check valve) are available, if you want to make it so that return pressure doesn't go into the solar panels. I have a check valve plumbed in just before the 3-port valve on my system. When the pump shuts off, the water in the panels cannot drain back through the filter and, therefore, back up into the drain and skimmer.
    blubluenoiseise

    My pool: 14,750 gallons in-ground plaster
    FAFCO Solar panels (seven 4' x 12') with a Goldline automatic controller
    1/2 HP WhisperFlo filter pump, Kreepy Krauly cleaner, Cartridge Filter
    Aquarite SWG, Satisfied user of the TF-100 Test Kit

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    Generally anything above 104 is too high, as the cell starts dying quicker.

    In your case it won't be much of a problem since it's only for few minutes.

    It's interesting that they say the cell will not function. I wonder if they have temperature sensor built in, which turns the unit off if the temperature is high.

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    I dont think there is a sensor, its more the salinity and conductivity which gives it a temp reading. At least that is what I think. There are times when the pool sensor and the swg are off by at least 3 degree's.

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    The controller can display the pool temperature, so that implies a sensor of some sort. I suppose it could estimate the temperature from changes in conductivity, though.

    Saying it's the pool temperature can be a bit misleading, since it's the last device in the flow chain. It's the temperature of the return water, which in the case of my pool is often 10-15 degrees warmer than the pool when the solar is doing its thing.
    blubluenoiseise

    My pool: 14,750 gallons in-ground plaster
    FAFCO Solar panels (seven 4' x 12') with a Goldline automatic controller
    1/2 HP WhisperFlo filter pump, Kreepy Krauly cleaner, Cartridge Filter
    Aquarite SWG, Satisfied user of the TF-100 Test Kit

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    Quote Originally Posted by bluenoise
    The controller can display the pool temperature, so that implies a sensor of some sort. I suppose it could estimate the temperature from changes in conductivity, though.

    Saying it's the pool temperature can be a bit misleading, since it's the last device in the flow chain. It's the temperature of the return water, which in the case of my pool is often 10-15 degrees warmer than the pool when the solar is doing its thing.
    Well conductivity can change depending on other factors, so i don't think they use it to calculate temperature. Temperature sensor seems to be the easiest and cheapest to implement

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    Every now and then, when my solar system turns on, the cell would shut off giving me a high salt error. The tech at Goldline told me that when the current in the cell gets above 8 amps, the unit will shut down and report a high salt error. He also said that there are two reasons why the current would get too high, too much salt or the water is too hot. Both increase conductivitiy and thus can create a high current situation and shut the unit off.

    One other thing, the cell does have a temp probe which is used to correct the salt reading that is displayed. If they did not do this the salt reading would depend on the temperature of the water and would be very inaccurate.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Bluenoise, I am pretty sure your solar is the last thing before your SWG, and your controller sensor would be right after the filter, so in essence the water returning from the pool gives you an accurate reading of pool temps.

    Rik

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    Before I installed the SWG yesterday, I studied the cell's guts. There is a little plastic protrusion inside that is likely the temperature probe.

    I was able to plumb the SWG in as the last thing before the water returns to the pool. My setup now has three temperature sensors feeding the controllers: One just after the pump to test pool temperature, one on the roof near the panels to measure heat available to the panels, and one in the SWG cell. The one in the SWG cell is after the solar, so when the solar controller asks for heating, that water temperature read by the SWG's temperature sensor is going to be warmer than the actual pool temperate as that water has just come from the panels.

    Separately, I have a digital thermometer in each of the solar pipes (send and return), so I can see the pool temperature on the send one and the heated water temperature on the other. These two thermometers are just for me to read and aren't tied into any of the control units.
    blubluenoiseise

    My pool: 14,750 gallons in-ground plaster
    FAFCO Solar panels (seven 4' x 12') with a Goldline automatic controller
    1/2 HP WhisperFlo filter pump, Kreepy Krauly cleaner, Cartridge Filter
    Aquarite SWG, Satisfied user of the TF-100 Test Kit

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    We have our SWG timed to activate after the pool timer comes on so the pump has already been running for at least 30 mins before the SWG turns on - however, even without it "running" the water still runs past the cell. There is a minute or so with some hot water, probably less than a minute and we do have the diverter set about 80% on solar at start up so we have some regular water running past mixed in with the solar.
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    Quote Originally Posted by NWMNMom
    We have our SWG timed to activate after the pool timer comes on so the pump has already been running for at least 30 mins before the SWG turns on - however, even without it "running" the water still runs past the cell. There is a minute or so with some hot water, probably less than a minute and we do have the diverter set about 80% on solar at start up so we have some regular water running past mixed in with the solar.
    The hot water by itself doesn't damage the cell (unless it's so hot that pipes start melting), it's the running in hot water that does the damage to the coating on the plates.

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