Breaker Trips On High Speed

[pogo3033]

I have a Hot Spot RLX ZQ model, the pump runs fine on low speed and sounds normal and has been running for a couple of days but if I switch it to high speed it sounds like it's straining and will trip the breaker after 15 to 20 seconds. I have the air control on MAX.

[TommyV]

IM NOT AN ELECTICIAN, but we just had a hot tub installed 3 months ago. we use a 50 amp breaker and a 50 amp gfci on the outside panel. we had to have this as a designated line for hot tub use only.... maybe your tub is wired in with other appliances on this line . so when you up your power intake. it trips because the line can not deliver all the electricity you need.. is your tub a 120v plug in model????? we were told that with this style or tub. if you are using the tub with the heater on and you want high jets on too. something has to give. 120v plug in model cant keep up with the hydro demand.. we have our tub.. hard wired with its own breaker.... hope this helps you...happy tubbin.

[pogo3033]

Thanks, yes I'm on a 115V 15amp house line but I don't think anything else is using the same line. I don't have an easy way to run a dedicated line to this outlet. I'm pretty happy just using the low speed and enjoying the hot water soak.

[Roger]

How old is the tub? Did this problem just develop or has it always done it since you plugged it in?

[PreservedSwine]

If this is a "new to you" tub, it's most likely just too long of an electrical run. (From the breaker box to that outlet)

The pump, when switched to high speed, draws more than 15 amps- only until the pump spools up to speed. If the pump is unable to spool up, the breaker will trip after a few seconds.

You can confirm/rule out voltage drop as the culprit by measuring volts at the spa while on low speed- one reading with the heater on, the other with the heater off. You should see less than a 4-5 voltage drop maximum when the heater is energized. If you're seeing more than than a 10% drop (say 123v low speed only, down to 112 with the heater energized), the electrical run is inadequate.

If there's a small acceptable drop (2-4 volts) the problem lies in the pump.

[pogo3033]

The hot tub is a 1998 model but in excellent condition. The voltage at my electrical panel on the breaker that supplies current to the tub is 118V. I checked the voltages on the main board and all 4 wires to the motor had voltage, so whatever tells the system what to do is telling both high speed and low speed to run. The wires to the motor had slightly varying voltages but all 115V or better. What I did was to pull the high speed wire from the circuit board and now it is running on low speed OK. So I might just leave it that way or wire another switch in to let me toggle in the high speed line. I know there are a couple of DIP chips on board and one Mosfet so most likely it's one of those that is the culprit but I have no schematic or instructions on what does what on the board. I do have 115V going to the heater, this was after a 10 minute delay so it's heating on low speed OK.

[Dr. Spa]

A 1998 model what?

With all the wires ATTACHED to the pump, ALL will read voltage (voltage will back feed through the non-powered speed, giving the appearance that it's being powered). IF, both the high and low speed were both being simultaneously powered, the motor would make a horrendous buzzing noise and not turn.

[pogo3033]

OK, 1998 model Hot Spot RLX ZQ ser 381166 I purchased this used from someone else. OK on the voltages. I have a idea that something on the circuit board that controls things may be defective. I know there is a Darlington DIP transistor on there and another larger chip that is labeled 53A4h and it has 28 legs however I have not been able to find out what it is. I would put a picture of the circuit board on here but I haven't been able to find out how to upload a photo to this site. I can use the tub as is since the heater is working and I don't mind even just sitting in it with just the low speed mode going.

Thanks for the info.

[PreservedSwine]

Did you check for voltage drop? - this is plugged into a 15 amp circuit, and can easily trip the breaker even if nothing is wrong with the spa- if the (house) wiring run is a long run from the panel. I think you're getting ahead of yourself troubleshooting the PCB- how abou this- to rule it out- Simply disconnect the pump wires from the PCB and energize high speed- and see if it still trips. If so, then you're onto something with the PCB- if not, stop looking at what isn't broken.

118V is fine at the breaker, but what you need to test for is VOLTAGE DROP, UNDER LOAD, AT THE SPA, to ensure that something is actually broken/not broken in the spa. Check the voltage at the spa on low speed, heater off. Then low speed, heater energized. If you see a 5% drop, it's not going to work. (The air control setting is inconsequential)