New Pool Setup Help

[venno]

Hi, after some delay my new pool has finally been installed but I need some advice on equipment selection and setup. My pool is a small one only a 3m x 5m 15000L one loacted in Perth Western Australia so a temperate climate. Its a chlorine pool with an auto dosing unit including acid as well (chemigem system).

I have Viron EvoP320 pump with a cyclone pre filter going into a Davey 25 inch sand filter. I am trying to get the most bang for buck from the 3 speed pump whilst keeping the pool clean. In the manaul for the sand filter it details the max flow rate and min backwash flow rate but it doesn't mention the min flow rate when in filter mode. I am trying to run the pump at low speed, approx 1450 rpm which notionally gives 140lpm according to manual, will this be enough for the sand filter?

Second question, I have seperate piping (suction and return) for a pool heating system and have purchased a heat pump (swimtek 8kw) and am looking for a suitable circulation pump. Ideally I want the quietest and least power hungry pump I can get, does anyone have any reccomendations?

Third question, how is the circulation pump for a pool heat pump system that is seperate to the filtration circuit typically controlled/actuated?

Cheers in advance

 

[JasonLion]

Sand filters work better at lower flow rates, so the lowest available speed is ideal for filtering. The lowest speed will also save you money on electricity. The only limitation is to make sure the speed is still fast enough that the skimmer(s) work well. Usually that isn't an issue, but in a few pools the skimmer(s) stop skimming at very low speeds.

For a heating you need something large enough to maintain at least the minimum flow rate required by the heater. What flow rate does your heat pump require?

It is highly unusual to have a separate pump for just the heater, so there isn't really a standard way that is handled. The simplest setup is to manually turn the heater and pump on and off together, though that is of course annoying. A fancier setup would use any of the common automation systems with it's own temperature probe on the filter pump to turn the heater and heat circulation pump on when the water is cold.

 

[venno]

Thanks for the info JasonLion,

The heat pump has 60lpm requirement which I think most pumps would be capable of, I was thinking that a small 0.5hp pump would be fine.

The control method you describe is exactly what I'm after. A temp probe in the suction line and a controller that runs the pump up at an interval to get a temp measurement and keeps going if heat is required and then shuts off when setpoint is reached. There are solar controllers available in Australia that do this but I have been unable to find any products that do this for auxillary heating methods (eg. non-solar).

Looks like there was one product on the market a while ago that did exactly this (a Dontek H7 controller) but seems like its not sold any more

 

[JasonLion]

Any solar controller with a relay (typically for a solar booster pump) should work. I'm not sure what is available in your area, but the Goldline GL-235 (with the optional relay) would be the obvious choice here.

 

[venno]

I ended up buying a secondhand pool filter/light timer clock unit for 60 bux, keep it simple for now and see how it all goes. Picking up a 0.5hp waterco pump on Friday to complete the system.