I inherited a used spa. It is a Seven Seas Spa made in 94. The tub is excellent and the blower and pump works great. I replaced the Element and flow switch in the heater before I filled it. Anyways, now when I run it on "no heat", the blowers, pump, light , all run fine, but when I switch the heat on, via the thermostat or timer, the system bogs down and it kills the whole system after like 8 seconds. Then, about 30 seconds later, you hear a relay reset or whever, and it kicks back on for a second, then off, then this continues. It doesnt trip the 240v 50GFCI breaker. The person I got it from said there was a problem with the heater, so really I'm just trying to fix their problem. I know the tub is 120/240 convertable, and was wired 240 at the place I got it, and at my place. I attached a photo of the control pack, but I cant find info on it(not sure of actual manufatcure) and Seven Seas Spas is out of business. Can anyone help with wiring diagrams and such???

OK, It looks like its a Brett Aqualine EM-190 Spa Control Pack, I found owners manuals and exact wiring diagrams for the exact model(26-z905NVX-5-ss). ANybody know what would make it trip off like this???

Since more info is probably better than less. The "Heater on" light does not come on ever(.note, the heater on ligh will light if I take one lead off one of the heater element studs and ground it). I measure 120V on each of the heater elemnent studs to ground, but measure nothing across the two studs(I was told I should read 240V across the two studs when its heating, but that may have been hearsay.

The new Flow sensor switch is 1-5PSI adjustable. What is that adjusting and where should it be?

There are only two contacts(blades) on the flow sensor. It shouldnt matter which lead goes to which, right?(Judging by the wiring diagram, it doesnt appear so.)

Thanks againn in advance.

you were told right, you should read 240V across the elements when operating correctly. With that in mind, you would also read 110v to ground as well. now, if you read the 110 but not the 220, you have lost one leg of the 220 and are reading the 110v through the element. I would look at the relay, most likely it's bad or if there are fuses involved check them. You are also correct on the flow switch connections.