Flow Error After Tub Heat Up

[bandito]

I have a Pacific hot tub with a Balboa heater model number PHT-400. After the tub heats up it goes into flow error. I have removed the filter and open the pressure switch. I also opened all the knife values and removed the filter. Jets seam to be working fine during heating.

It has been suggested to me that it may be either the impeller or the pressure switch. My hut tub has to pumps. One is strictly a circ pump and the other is the high/low for the jets. I have attached two pictures. One is of what I believe is the pressure switch with the valve fully open locate on the left side of the heating tube. The other is what I believe to be a flow sensor switch which is located at the entrance of the circ pump.



Any ideas on where to start diagnosing? Is there any way to test a switch/sensor or an impeller?

 

[YippeeSkippy]

I get a Flo Error when there is air in the lines. When Skippy forgets to fill the tub with the hose laid in the filter area which fills through the pipes and expel any air.

 

[bandito]

I get a Flo Error when there is air in the lines. When Skippy forgets to fill the tub with the hose laid in the filter area which fills through the pipes and expel any air.

I filled the tub with the hose in the filter area then turn on the tub. When I checked the tub a while later it was at 85 degrees but set for 100. I attemped to turn the heat down to 80 but when I got to 85 it went into flow error. I guess I have to test the flow switch and sensor?

 

[bandito]

So tested both and neither has continuity. Basically the pressure switch has four wires. Two come from the panel and go to the pressure switch. The other two from the pressure switch to the flow sensor. There are only two connectors on the pressure switch each receiving a wire from the flow sensor and the panel connected in parallel. Check the drawing that I made.



I tired adjusting the dial on the pressure switch but the only time I would get continuity was when I touched the wires from the flow sensor. I take it I have a bad flow sensor but does the pressure switch itself do anything other than have a dial on it?

One last thing about the flow sensor. If I pressurize it by blowing air into it I get continuity which now makes me wonder if it's just the circ pump not creating enough pressure.

 

[YippeeSkippy]

I know bupkis about electrical circuit stuff. That said, I just wanted to mention that my hot tub's lowest setting is 85, and I can't set it any lower. It will give me a temp reading of lower than 85 when I'm filling it up though.

 

[bandito]

I know bupkis about electrical circuit stuff. That said, I just wanted to mention that my hot tub's lowest setting is 85, and I can't set it any lower. It will give me a temp reading of lower than 85 when I'm filling it up though.

Thanks for the reply. I can set mine from 80-100 degrees. When first turned on it sets itself to 100 degrees.

 

[bandito]

I replaced the main pressure switch on the tube. I set it to the lowest PSI, same problem occurred. I then set it to 2 PSI which is factory spec. Better but the problem eventually occurred. I disconnected the pressure switch for the circuit pump so the only switch connected at the moment is the heat tube one. Runs like a charm. Question..how important is the pressure switch for the circ pump? Do I really need it it?

 

[Isaac-1]

This could also be a sign of low flow from a dying circulation pump

 

[bandito]

I had the circ pump test by a local shop. They said it produced 3-5 psi which is correct.