My outdoor plugs are on gfi and the pump unit also has an inline gfi.

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1993 e300
1995 e320
1994 e320
2006 s500 4matic
2004 Jeep wj overland
2001 Ducati 748
2004 Honda shadow aero

Got it dialed in

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1993 e300
1995 e320
1994 e320
2006 s500 4matic
2004 Jeep wj overland
2001 Ducati 748
2004 Honda shadow aero

I’d put a thermostat on the outlet side from the fire pit heat exchanger. Thermostat opens and closes cold water mix. You could end up with a steam jet coming out if you don’t have a cooling system. Also a relief valve if you get too much heat expansion = pressure. https://en.m.wikipedia.org/wiki/Charles%27s_law

Also a check valve on the pump outlet before the fire pit. Water expands on heating. Increases pressure. You want that pressure to go one way, not push back into pump.

Guessing.

Check valve ya but don’t really need anything else being that it’s an open pipe system. As long as water is going through the exchanger and then going downstream into the Hot tub Is only purpose

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1993 e300
1995 e320
1994 e320
2006 s500 4matic
2004 Jeep wj overland
2001 Ducati 748
2004 Honda shadow aero