How to diagnose hot tub pressure switch flow problem

Hey. What we’re gonna do right now is change a pressure switch. Most part actually is qualify pressure switch to be changed. A bit of a diagnostics that go into looking over the pressure switches themselves. This here is a pressure switch. We need to understand, right off the bat, a pressure switch has two error codes. They’ll come off your top side display. One error code is FLO. The other one is FLC. Flow switch open, flow switch closed. The purpose of your pressure switch is to measure pressure in the line when your pump is running. So your pump comes on low speed. This switch has a diaphragm side of it which is going to go up, close the contact between these two points.

If it does not close the contact you’re going to get an FLO. which means flow switch open because the contacts have not closed. Obviously, FLC., flow switch closed is the opposite. If the pump is not running but the diaphragm is closing the contact you’re going to get FLC because it’s closed when it’s not supposed to be.

So, what I have here is we’ve got a pack with some power hooked to it and we’ve got out cable, which is your pressure switch cable, right up to the pressure switch on this heater, and we’ve got FLO. FLO is coming on the top side. First thing you’re going to do when go to someones house and they call when they have a problem with FLO error is taking a look in the tub and we’re going to make sure of two things. One is pump one is actually running on low speed and two, that there’s movement of water within the hot tub.

Okay? So, if we have movement of water in the hot tub and pump one is running and the water is moving. So the water is running through this heater bearer and we still have FLO we’re going to say, “Hmm. There’s got to be something wrong with this pressure switch”. These pressure switches are non-adjustable. What you’re going to need is a jumper. Here’s our jumper. I just took some green wire, stripped both sides. I mean, you could just bend a nail in half. It really doesn’t matter. We’re going to jumper across these two leads right there just to make electrical contact between the two of them, FLO’s gone. Now, it’s going to send power to the heater to allow the tub to heat. Pull that off. Back to FLO. Connect across. FLO’s gone and it’s running.

So, at this particular time I would know that everything is running and this pressure switch is faulty because it keeps going to FLO. I can jumper and make it work. That’s a lot right here. And the FLO goes away. You know that there is no malfunction within the board, end of the operation, or this cable. Everything is running perfectly fine up ’till this switch.

Changing it, I mean, I don’t think we need to go too far into it. It’s threaded fitting. Thread it out. Take a new one. Thread it in. Plug in your contacts. You’re good to go. Now, if you have an FLC, which means it’s reading closed when it’s not running. So, you’re going to go again. Qualify. Make sure the pump is not running and there’s no movement in the tub. There’s nothing flowing through this actual heater and it’s going FLC which means it’s closed. You can simply just pull one of those leads off and it should go to FLO or it’ll just clear itself, right. So, you pull one of the leads off. FLC goes away and you’re fine and running you know again it’s the pressure switch.

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