Tom 7506 Posted February 6 Report Share Posted February 6 I have a hot tub with a Balboa VS500Z controller and a ML200 control panel. At first, I couldn't reset the breaker. After some troubleshooting I found the heated coil had shorted. I replaced the exact OEM coil. I checked on it the next day and it had an OH overheated code. I followed the Balboa troubleshooting chart for OH and didn't find anything wrong. With the tub set to keep the temp between 102 and 104, I found the tub at 109° on the way to overheating again. There should not have been any voltage to the heater. I clamped both power lines to the heater and found one line running 120v at 12 amps. The other line had no voltage. Am I correct in thinking there's an issue with the circuit board. I read somewhere the problem is almost always the front panel. Help! Quote Link to comment Share on other sites More sharing options...
CanadianSpaTech Posted February 6 Report Share Posted February 6 12 hours ago, Tom 7506 said: I found the tub at 109° Was the water actually at 109? When you installed the heater element did you look down the tube and ensure the element was centered in the tube and not touching the sides. 12 hours ago, Tom 7506 said: I clamped both power lines to the heater and found one line running 120v at 12 amps. The other line had no voltage. Disconnect the heater from the board and lift the 2 copper tabs up so they don't touch anything then verify you get 240V off the 2 copper tabs when the heat indicator light on the topside is solid and not flickering. If you don't get 240V then you likely have a blown heater relay. Remove the board and have a look on the back for bark or burnt areas around the relays. Quote Link to comment Share on other sites More sharing options...
Tom 7506 Posted February 6 Author Report Share Posted February 6 Yes, water was at 109. Yes, I verified the coil was centered in the tube, nothing was touching the sides. Sounds like I'm pulling that board. I'll get one on order. Do you try to repair these or just toss them? Thanks for the prompt response! Tom Quote Link to comment Share on other sites More sharing options...
CanadianSpaTech Posted February 6 Report Share Posted February 6 7 hours ago, CanadianSpaTech said: Disconnect the heater from the board and lift the 2 copper tabs up so they don't touch anything then verify you get 240V off the 2 copper tabs when the heat indicator light on the topside is solid and not flickering. Follow above. Turn the temp up so the heat light goes solid and test... Do you get 240V? Then turn the temp down 5 degrees and wait until the temp light goes off then test. Do you still get 240V? If you get 240v with the heat light off you have a stuck heater relay (and may be why the first one failed) If you don't then likely the issue is elsewhere. What do you have your filter cycle set at for duration and frequency? Filter cycle set for to long and the pump running longer than it should can heat the water above the set point. Relays can be replaced Quote Link to comment Share on other sites More sharing options...
Tom 7506 Posted February 7 Author Report Share Posted February 7 It appears all the default timeouts and filter cycles are set to default: 2 hour filter cycle, 2 hour low speed and 15 minute high timeout. I was thinking, once you mentioned the stuck relay, it might have contributed to the shorted heater coil. I just don't know the history of it overheating as the rental just came to us recently. So now I've ordered a new board to replace the old one and a new coil to repair the old heater. I'll look into replacing the relay so we have spares. Quote Link to comment Share on other sites More sharing options...
Tom 7506 Posted February 16 Author Report Share Posted February 16 Update: ARGGG! I checked the hot tub the next day and was pleased to find it was at 104°. A few days later, we heard from a guest that it wouldn't awaken from "sleep" and was too hot. I went back yesterday and found it had a code HH (different from the first code OH), 120° and the pump was on hi speed. That explains why the control panel wouldn’t respond. I'll note here that the OH means the spa saw 110° and HH means is saw 118°. Both times I recorded temps quite a lot higher. I have now installed a replacement OEM heater tube and OEM main circuit board. The new circuit board has identical dip switch settings and jumper wires. I also verified the replacement board has identical model and version numbers. All the jets are open and the water is roiling so it's certainly not a flow issue. I turned off the power for now. When I received the new board, the jumper wires were configured differently from the old. I called Spa Guts support and they basically said if it was working with the wires in the old configuration, go with that...so I matched up the connections using the old board as a template. Is this a problem? So, I’ve run up against 2 issues so far. First, the coil had shorted so I replaced it with a new OEM heater and sensors. Second, 120v power was going to the coil even after the tub reached its set temp. I suspected a stuck relay on one side of the 220 power to the coil so I replaced the controller board. Plan: When I go back, the tub should be cold. I'm going to power it back up and do some checking. First, I’ll pull the tabs to the coil and make sure I have 220 to the coil. I’ll also make sure the amperage across both sides of the 220 are roughly the same. What else should I look for? It's going to take a few hours to get to 104. Question: why in the world is power continuing to be applied to the heater coil after reaching operating temp. I am aware the temps I’ve found are dangerous and will make sure we won’t allow any users until I get this figured. I appreciate your time look and welcome your help…again! Tom Quote Link to comment Share on other sites More sharing options...
CanadianSpaTech Posted February 16 Report Share Posted February 16 Post pics of the new board installed. In the photo W1 (white wire beside where pump 1 connects) should go to "White AC" if you have a 120V pump. In the photo it is connected to "Red AC" and that is for a 240V pump. Could you have a stuck button on the topside? ML200s have a high fail rate. Quote Link to comment Share on other sites More sharing options...
Tom 7506 Posted February 17 Author Report Share Posted February 17 Yeah, that's a pic of the new board before I noticed they were wired differently. The old card and the new installed card have white AC to W1. I checked and double checked they were wired the same...I don't have an installed pic. It's 25 miles away. This is a pic of the old board which I was going to try to repair. I was also struggling with the dip setting A5. dips.pdfdips.pdf I assumed the pump ran on high and low speeds. Panel: I know the temp up and down buttons work. The lights can be turned off and on. When an error code is thrown, the jets button does nothing as the pump stays on high. Could a bad panel cause overheating? Your suggestion above about a stuck relay? The old card had no obvious damage on the back so I tested both with a 9v batt and continuity tester. I got a good "click" and the circuit closed on both. Tracing the circuit, both relays get the same signal from J12 so why only 120v when I tested. My brain hurts. Quote Link to comment Share on other sites More sharing options...
CanadianSpaTech Posted February 17 Report Share Posted February 17 10 hours ago, Tom 7506 said: When an error code is thrown, the jets button does nothing as the pump stays on high. Ok stuck pump button on topside?...or pump itself not switching high to low to high. Disconnect the pump from board and test power coming off the board to each speed. White to red, white to black. A pump running continuously generates 150 160 + degrees and can overheat the water from within. Re dip switch: photo unavailable and can't see it in schematic photo. Quote Link to comment Share on other sites More sharing options...
Tom 7506 Posted February 17 Author Report Share Posted February 17 Quote Link to comment Share on other sites More sharing options...
CanadianSpaTech Posted February 17 Report Share Posted February 17 A5 on for 2 speed pump 1 (no circ pump in tub) Quote Link to comment Share on other sites More sharing options...
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