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Thread: Pump Flow, Electric Heater along with solar heating panels

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    Join Date
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    Pump Flow, Electric Heater along with solar heating panels

    I am about to have a KStar 5k watt electric heater installed to top up my solar heating system. I have a two speed 1 HP Hayward Powerflo Matrix. At high speeds it claims around 80GPM of flow rate and half that at half speed. That means around 40 GPM at low speed. I ran my solar system most of the summer at low speed and it worked great, almost as well as at high speed.

    The KStar has a maximum flow rate of 8 GPM. Even if you run a bypass around it how will the 40 or 80 GPM drop to below 8? Are there variable bypasses which dictate the percentage of water going to each piece? That is, the water splits into two paths and somehow more goes into the heater path. Perhaps the GPM for pumps, heaters and solar panels refer to different things?

    The electric heater is only going to be used to top up what the solar doesn't do. I basically want 70F minimum in May and October in Toronto.

    Would it perhaps be better to place the electric heater closer to where the pipes start climbing to the solar panels (25' away from the pump) as opposed to closer to the pump?

    I realize that gas or perhaps a heat pump would be better but the extra cost and noise of a heat pump seems overkill for such a small pool while the installation of a gas heater is not feasible in this case.

    Thanks,

    Philip
    Philip
    12.5x21.5x52" on-ground 29" below ground (6000 gallons water), .85 HP Hayward SP26115VSP , Hayward XStream 100 sq.ft. cartridge filter, Hayward AquaRite salt system, 160 sqft of Aquatherm solar panels on 12' high flat roof 25' away from pump, Goldline auto controller for solar, Heat Pump, May->October @77+ in Toronto, Pool Python.

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    linen's Avatar
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    Re: Pump Flow, Electric Heater along with solar heating pane

    You will not get 80 gpm with that pump...more likely 40-50 gpm depending on your plumbing. It will only get 80 gpm if your plumbing head loss is less than 25 foot. How many panels do you have and how are they configured? Most likely you will get more heat with the pump on high.

    Skip the 5K watt heater, it won't make a dent in your pool temperature, but will make a dent in your wallet.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: Pump Flow, Electric Heater along with solar heating pane

    I have 75% coverage for the solar panels. They do work better on high, but really marginally. Seems odd but the pool temperature on low was very similar this year to the previous 7 years with only high.

    Solar alone won't get me October in Toronto. Electricity is just over 6 cents a kw so heating the pool 10 degrees won't cost much. The other option would be a solar heat pump but they are very expensive and noisy. Gas is just not something I personally want for many reasons, including the initial difficulty of setup.

    Philip
    Philip
    12.5x21.5x52" on-ground 29" below ground (6000 gallons water), .85 HP Hayward SP26115VSP , Hayward XStream 100 sq.ft. cartridge filter, Hayward AquaRite salt system, 160 sqft of Aquatherm solar panels on 12' high flat roof 25' away from pump, Goldline auto controller for solar, Heat Pump, May->October @77+ in Toronto, Pool Python.

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    mas985's Avatar
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    Re: Pump Flow, Electric Heater along with solar heating pane

    Are you using a pool cover? That could help extend the season.

    The main problem with the heater is that it is very small and even running it non-stop may not give you more than a 6 degree gain without a pool cover. Pools can easily lose 6 degrees overnight in heat loss without a pool cover. Plus the heater and pump together would end up running you about $8.50 per day.
    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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    Re: Pump Flow, Electric Heater along with solar heating pane

    Quote Originally Posted by mas985
    Are you using a pool cover? That could help extend the season.

    The main problem with the heater is that it is very small and even running it non-stop may not give you more than a 6 degree gain without a pool cover. Pools can easily lose 6 degrees overnight in heat loss without a pool cover. Plus the heater and pump together would end up running you about $8.50 per day.
    I stopped using the cover out of laziness. I know I should but I also know me and it's not going to happen.

    The pump is always at 1/2 speed and uses very little. I've compared the use before and after and the pump has been fantastic.

    Don't forget that the solar cover is still working and really I can deal happily with 70 F. It's only May, September and perhaps October that I would need a 6 degree net gain every now and then.

    I do see your point. I thought I could get 6 degrees net by running it for 5 hours.

    Well you do have me thinking and I have gone back to looking at heat pumps.

    The pool yesterday was at 66 at 4PM ( when I go swimming). I was really cold overnight and the pool today at 4PM is still 66. The solar probably increased it during the day. Should have measured it this morning. Still it would take much to get me to 70.

    I realize I sound a bit crazy as I don't care too much about costs ( not because I won a lottery or equivalent). The whole pool never made sense financially. I just love swimming "lengths" every day.

    Have you had any experience with the K-Star electric heater? You need to regulate the flow down to 8 GPM through it. It's not obvious how one does that. I see the heater container is small, like a kettle sort of, but there are only 7k gallons in the pool. The claim was that if properly set up I would get roughly 2F increase per hour.

    Philip
    Philip
    12.5x21.5x52" on-ground 29" below ground (6000 gallons water), .85 HP Hayward SP26115VSP , Hayward XStream 100 sq.ft. cartridge filter, Hayward AquaRite salt system, 160 sqft of Aquatherm solar panels on 12' high flat roof 25' away from pump, Goldline auto controller for solar, Heat Pump, May->October @77+ in Toronto, Pool Python.

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    linen's Avatar
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    Re: Pump Flow, Electric Heater along with solar heating pane

    I would figure out how to make your solar cover easier to take on and off. There are many examples if you do a google site search (near upper right of page). That will be the most cost effective and easiest way to keep heat in the pool regardless of adding any sort of heater. A heat pump may not be the best choice since their efficiency drops as the ambient temperature drops and some don't even function below an ambient temperature of 60F.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Pump Flow, Electric Heater along with solar heating panels

    Quote Originally Posted by linen
    I would figure out how to make your solar cover easier to take on and off. There are many examples if you do a google site search (near upper right of page). That will be the most cost effective and easiest way to keep heat in the pool regardless of adding any sort of heater. A heat pump may not be the best choice since their efficiency drops as the ambient temperature drops and some don't even function below an ambient temperature of 60F.
    Not going to happen. I'd rather go to the local pool. The heat pumps that only work at 60F are older. I am not really interested in cost effective. If I were I never would have had the pool installed.

    We aren't talking a great deal of increase. As I have said, 70F is fine. I swim in 66F every day. The electric heater from K-star would work but as someone mentioned here it has certain drawbacks.

    My original question really had to do with a method of slowing the flow to the electric heater, if I were to go that route.

    I am not opposed to covers but everyone I know with them simply don't use them because of the hassle. An automated over would be great but those are very expensive.

    I seem to have narrowed it down to the K-star ( which mas985 pointed out some important points) or a heat pump which works at 45F and up. There are some from HVAC-Concept that will even work at freezing.

    Sorry to be so negative regarding the covers. I think you underestimate how lazy some of us are

    Philip
    Philip
    12.5x21.5x52" on-ground 29" below ground (6000 gallons water), .85 HP Hayward SP26115VSP , Hayward XStream 100 sq.ft. cartridge filter, Hayward AquaRite salt system, 160 sqft of Aquatherm solar panels on 12' high flat roof 25' away from pump, Goldline auto controller for solar, Heat Pump, May->October @77+ in Toronto, Pool Python.

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