OH Code on Balboa Spa, Debug?

[natenewz]

Hi, I have an older hot tub that I bought used. I'm pretty sure it was made by combining parts from several. I want to run in the "F3" mode instead of the "FC" mode to save power by not running the pump continuously all the time, however when I put it in "F3" mode after some time (longer than an hour, less than a day) it throws the "OH" code and stops running until I reset it. To be clear, when it is in the "FC" continuous mode, it does not throw the code.

So, my question is: Where do I start debugging? I've already replaced the limit switch recently for a different issue, so I don't think that's the issue.  I can use a multimeter and solder if needed, but just wondering for likely culprits.

http://imgur.com/a/BULJE

Above are some pictures of the control panel.

[Jersey Hot Tub Repair]

Does your tub have a circulation pump or does it use pump 1 for heating?

[natenewz]

It just has the one main pump for circulation and jets.

[Jersey Hot Tub Repair]

Sounds to me like the heater is remaining on when the pump turns off, which should not happen.

You'll need to do this with power applied, so be very careful; 240 volts is not something you want going through your body.  Check the pressure switch for continuity with the pump running and with the pump off.  You should have continuity when water is flowing, and no continuity when the water stops flowing.

Continuity from the pressure switch means that the circuit board thinks it's okay to turn the heater on.  If the heater comes on when the pump's not running, the water in the heater can will heat up very quickly and trip the high limit sensor.

 

[natenewz]

Okay, I checked it like you suggested. When I came home from work, the OH code was flashing, pump was off. I checked for continuity on the pressure switch, and it was an open. Then I reset the tub and turned the pump on the slow circulation setting. I checked the continuity again while it was running and it was a short.

So it seems like the pressure switch is working correctly. Also, I realize now that in my original post, I said I had replaced the limit switch recently. I was confusing the limit switch and the pressure switch. I had recently replaced the pressure switch that I just tested, not the limit switch. 

Thanks for your help so far,

Nate

[Jersey Hot Tub Repair]

Are you sure you have programmed it correctly?  Do you have the instructions or are you just pressing buttons and assume you've set it to filter part time?  Here's a link to a Balboa instruction guides for different topsides:  http://www.balboawatergroup.com/Topside-Spa-Panels

OH usually means the water temperature went over 112 degrees and the hi limit switch shut it down.  It typically happens when the pump stops pumping and the heater remains on.  That's why we were checking the pressure switch.  The fact that you were fine with continuous filtering and overheating on F3 made me think your heater isn't shutting off.  Also, since you said you recently replaced the pressure switch, that also makes me wonder if the switch is properly adjusted.

So, first of all, is the water temperature anywhere in that range?  If it is in fact hot enough that your spa is overheating, let's check the pressure switch.  You're going to have your voltmeter inside the spa when it's running, so be very very careful.

With your meter leads across the heater element terminals, you should read 230 VAC.  Is that correct?  When you get 230 VAC across the heater element terminals, the heater is working.  Now, disconnect the pump and quickly check the voltage.  That doesn't mean press the JETS button to turn it off, it means pull the PUMP1 plug out of the control box amp connector.  Does it remain at 230VAC?  If so, your heater is not shutting off, which is why you're overheating.  Another telltale sign is you will hear the water in the heater boiling, at least until the hi limit switch shuts it down.

Let us know what you find.  And be very careful, we don't want to read in the paper that you were electrocuted.

 

 

 

 

 

 

 

[natenewz]

Hi ScubaDave,

I will check on the instructions you posted, but I don't think there is that much adjustment available. I think you can only change F3, F6, F9, or FC as well as setting the temperature. I have the temperature set to 80 degrees right now, and the water is less than 80 degrees when I reset it. I'll dig into that more this evening.

I tried what you suggested and  reset the tub, the pump and heater turned on. I measured 220-240V across the heating element. I then unplugged the motor while it was running and the heater stayed on at the same voltage and started boiling water in the pipe. So I think that is the issue. Do you think the pressure switch needs adjusted, or something else? I wondered about a sticky heater relay, but if that was the case the tub would overheat when in "FC" mode wouldn't it?

Thanks for your help so far.

Nate

[Jersey Hot Tub Repair]

Nate,

If the heater stayed on with the pump disconnected, either your pressure switch isn't adjusted properly, the circuit board relay isn't opening the heater relay, or the circuit board logic isn't telling the heater relay to open.

Just to double check the pressure switch, with the tub heating, pull one of the wires off of the pressure switch.  That should turn off the heater.  If it does, than your pressure switch is doing it's job and the problem is at the circuit board.  If the heater stays on, the pressure switch may be bad, miswired or misadjusted.

 

[natenewz]

Hi ScubaDave,

I have good news and bad news. The good news is that I found the issue based on your last message. The wire connecting the pressure switch to the circuit board was broken in the harness somewhere. I measured continuity from one end and the other and only one of the wires was working. So I made a new harness using the old end and put it in.

The bad news was, when I was taking it out, I broke the plastic fitting connecting the pump impeller to the heater inlet and had to plug the whole and tap a new one. So I drained the water out to fix that, and filled it back up again. I turned it on to see if all was well and got an Sn code. I didn't know what the code meant, so I turned it off and back on again. Somehow the 2nd time the heater was getting very hot and melted the sensor that sits in a metal pocket right next to it. I disconnected the heater element and tried turning it on to get the pump going, but the pump won't turn on because of the damaged sensor. I read the Sn code means there is a problem with that sensor, and I know it's damaged because it's black and smelled bad when it happened. The weird thing was that when the heater was getting very hot, I didn't hear boiling water like before in the heater tube, so I'm not sure how that's possible since the tub was full when I turned it on. Either way, I'm going to pull the damaged sensor out and order a new one.

Unfortunately, it snowed 12" last night after all this happened, so I've got a cattle heater in the tub keeping the water from freezing while it's off.

Thanks for your help, I think it's close to fixed. Let me know if you have any suggestions or ideas.

Nate

[Jersey Hot Tub Repair]

Several thoughts:

I can't picture what you mean about breaking the pump impeller fitting and having to tap a new one.  I assume that since you said you repaired it, it's not part of the problem.  I'd love to see a picture of what you're talking about if you have a moment to share that.

 

 

 

 

[natenewz]

Here are pictures of the pump impeller fitting, and where I had to tap a new hole. The original plastic fitting snapped off and then the hole started squirting water all over the place. I also took a picture of the burnt up hi limit sensor.

http://imgur.com/a/Y6bv4

[Jersey Hot Tub Repair]

The hose between the pump faceplate and the heater is give a path for air to bleed out of the pump.  If you fill the hot tub by putting a hose in the footwells, water gets into the drain and all the air in the drains gets pushed through the plumbing, often getting trapped in the pump.  By providing that hose, the air has an escape route to prevent an air-lock when you turn the tub on.  That's why you always want to fill the hot tub through the filters, because then the water (theoretically) goes to the pumps first and pushes the air out of the pumps and further into the plumbing where it will get pushed out when the pumps turn on.

Did the fitting break on the PVC elbow by your heater?  It looks like that's got a brass nipple and I'm assuming that's what you put in.

I never saw a hi limit sensor burned up like that before.  Maybe the heater came on with no water in the heater can, and the pressure switch isn't adjusted properly and let it burn up?  On monday, you said the heater came on, but you also said the pressure switch wiring harness was broken.  That shouldn't occur.  With a broken wire, the pressure switch circuit isn't closed, and the heater isn't supposed to come on.  If it does, it indicates a problem with the circuit board.

If you remember your message from last week, you said you were working fine until you changed the filter cycle from "always on" to F3.  So, with the pump running 24 hrs, the heater can run without getting an error.  Of course,  since the tub wasn't overheating at that point, the temperature sensor control of the heater was probably working and turning off the heater when appropriate.  Which makes me think that the pressure switch logic on the circuit board isn't working properly.  Either way, it still sounds like a circuit board issue.