Circulation line restricted


New member
Jun 3, 2012
I have a Sundance 880 Optima spa. I am getting a FLO error. The pump is new, the flow switch is new. The flow switch closes partially when the pump is running, but not completely, so I get the error. This pump discharges to a 1.5" line that runs under the bottom of the hot tub. There is a tee off of this line with a 3/4" hose that runs to the heater, then to the flow switch, then around the side of the hot tub, buried in insulation.
I took a spare piece of 3/4" hose, 10' long and installed it on the outlet of the flow switch and just ran it back into the tub. With this, there was plenty of flow to close the switch and everything works as it should. This tells me that there is a restriction somewhere in the line downstream of the flow switch. I used a shop vac to suck water back thru this line to try and remove any contaminants that might be blocking it. I removed about 10 gallons of water this way and did not see any debris, at least not anything significant. After this, I tried to blow thru the line with the shop vac to blow anything out. I thought that I would see bubbles coming out somewhere in the tub by doing this and could determine where this line is routed to, but I did not see any bubbles and cant be sure that I was getting any air flow thru the line by doing this. I hooked it back up to the flow switch outlet and powered up the hot tub, and still not enough flow to close the switch.
I do not have the filter in, so I know that its not a problem with suction/air lock on the pump.


In The Industry
Mar 21, 2020
Cabool, Mo
Post a pic of your equipment area.
The heat return/ ozone line runs to the heat return jet(s). There is one on the wall in the footwell and usually another higher up or in the filter well.
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