Does anyone know if a 2 speed 2hp Hayward Tristar pump will typically have enough water flow to operate the Hayward H-Series Universal Lo Nox Heater? This system has 2.5" PVC suction/return with about 50 foot run to pool. On low speed the Hayward Nav actually works. If the heater does not come on in low speed, can we adjust the Pressure Switch in the heater until it comes on? The pool and equipment are level. I understand that Hayward improved the flow through the Heat Exchanger, so I'm wondering then if a greater gpm is now required to create enough back pressure for the Pressure Switch. Any help here?
Low speed (2 speed Tristar) enough flow for heater?
- Thread starter Rover5
- Start date
- May 3, 2007
- 16,875
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Most pressure switches don't require much in the way of pressure to keep closed. I have 1/2 HP two speed and the heater can work on low speed although it isn't recommended below 40 GPM. But I think in your case, low speed should be well above 40 GPM so there shouldn't be any issue. However, be aware the the temperature difference between inlet and outlet will double with low speed. So a 400k BTU heater run at 100 GPM will raise the water temperature by about 8 degrees but at low speed by 16 degrees so the water can have a much higher exit temperature.