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Help Model J-470 watchdog mode.


Chuck2jz

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I bought a j-470 used that suposedly just needed pumps. Installed some new pumps, and filled the hot tub up. both the jet pumps were runing (stuck on) and i didnt think much of it at the time. I figured that was normal untill it got up to temp. In the AM after filling it up it was at 92deg and just the circ pump was running. i tried to turn on the jet pumps and imediatly i heard a click (most likley the sound of a relay clicking) and it went into watchdog mode. I reset the tub and it did this 3-4 times, untill eventualy it just went into watchdog mode as soon as i fliped the power on.

List of things i have checked.

-Temp sensors, both seamed to read ok.

-Voltage supply, was good.

-the rosstech, is unpluged  

-tranformer wasnt shorted out between the two fields.

-Heater reads 10.4 ohms

I am starting to think maybe the board is fried or posibly the controll unit. hopfully someone on here can help!

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1 hour ago, Chuck2jz said:

Temp sensors, both seamed to read ok.

Define "ok". What were the readings?

1 hour ago, Chuck2jz said:

Voltage supply, was good.

Define "good".

1 hour ago, Chuck2jz said:

tranformer wasnt shorted out between the two fields.

It never is. Did you test output voltage?

1 hour ago, Chuck2jz said:

Installed some new pumps,

Same voltage and amp draw as the old ones? 

90% of the time this is a faulty sensor. 

 

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57 minutes ago, RDspaguy said:

Define "ok". What were the readings?

Define "good".

It never is. Did you test output voltage?

Same voltage and amp draw as the old ones? 

90% of the time this is a faulty sensor. 

 

-I will have to check temp sensors again tomorrow. but i belive they were within 500ohms of eachother. I also checked the watertemp with my heat guy and it was within a couple degrees of what the chart listed for the sensor.

-voltage read 120 +/- 2 degrees at the main power buss and was consistant at that right up to the relays/fuzes. I also forgot to mention above that i checked all the fuzes aswell.

- I did test output voltage of the tranformer, but not totaly sure what I'm looking for. i will take some photos/try and get some voltage readings tomorow and make an update.

-old pumps were 2.5hp continous 5.1hp max 3450rpm at 11.7amps, new pumps were labled aas 4hp 3450rpm at 12amps same rpm(i was told by the dealer that they would be compatable). hopfully that 0.3 of an amp is fine. they did run for a long time continuasly atleast 5hrs before i went to bed. 

The other thing i noticed in the AM was the rosstech was hot, not sure if this unit could some how cause the error? I thought it was just for the speakers and lighting, but I'm not totaly sure. thanks for the responce, and I apreciate the diagnostic help. All the local spa tech Companies are a month plus out at the moment. Talking to them on the phone didnt inspire alot of confidence in me that they would be able to fix it. They said probably needs a new board and controll pannel.

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Here are the curcuit board pics, and the specs and readings I took off the tranformer. I also included a couple pics of the rosstech an where it looks like the curuit board inside looks posibly damadged.

Looking at the ohms on the temp sensor/high level makes me think that they could likley be the cause. The thing that concerns me is, why did the jet pumps run continously when they were working? maybe there is somthing else wrong aswell?

board capasitor close up.jpg

circuit coard.jpg

curcuit board 2.jpg

transformer in.jpg

transformer in 2.jpg

transformer out 1.jpg

tranformer out 2.jpg

transformer out 3.jpg

transformer out 4.jpg

rosstech.jpg

audio. lighting box.jpg

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6 hours ago, Chuck2jz said:

I also included a couple pics of the rosstech an where it looks like the curuit board inside looks posibly damadged.

Check the fuse inside... but they are also known to blow holes in the board.

@RDspaguy I made up one of these for testing Jacuzzi sensors. Comes in handy

Screen_Shot_2019-02-26_at_10.13.51_AM_copy__24684.1551200492.1280.1280.png?c=2

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Are you testing to ground? Your test leads must both be on the red and black wires to test 240v, testing to ground tells you nothing. Same with the transformer, test blue to blue, yellow to yellow, then yellow to blue (any).

The pumps running is a response to a higher temp reading on the high limit than the temp, and will usually show OH error, which could be a sensor going out, or a flow restriction through the heater, or a stuck heater relay. 

Do you have 240v across the heater terminals when you shut it off to test sensors? Residual heat in the element will cause a temp discrepancy if water flow is stopped while the element is hot.

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14 minutes ago, CanadianSpaTech said:

Check the fuse inside... but they are also known to blow holes in the board.

@RDspaguy I made up one of these for testing Jacuzzi sensors. Comes in handy

Screen_Shot_2019-02-26_at_10.13.51_AM_copy__24684.1551200492.1280.1280.png?c=2

Yep, got one. You can actually order them ready made with a push button for the pressure switch. Handy to have, but it won't help find a flow issue or faulty sensor, just a board or calibration issue. I can't remember the last time I actually used it. My second job in this biz was a Sundance dealership, in '97-'98, and they were standard issue then since the boards had a sensor calibration that was actually adjustable in the field. They got rid of those decades ago.

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4 hours ago, RDspaguy said:

Are you testing to ground? Your test leads must both be on the red and black wires to test 240v, testing to ground tells you nothing. Same with the transformer, test blue to blue, yellow to yellow, then yellow to blue (any).

The pumps running is a response to a higher temp reading on the high limit than the temp, and will usually show OH error, which could be a sensor going out, or a flow restriction through the heater, or a stuck heater relay. 

Do you have 240v across the heater terminals when you shut it off to test sensors? Residual heat in the element will cause a temp discrepancy if water flow is stopped while the element is hot.

-Ok i will re test for proper voltage.

- When all three of pumps were running non stop, the only thing flashing was ICE and then COOL and the tempurature. There wasn't any error codes at this time. now with watchdog ---- mode nothing turns on, it imediatly gois into the error mode.

- i have both the temp sensor and high level out of the tub as i was trying to scource new ones today. I'm picking up a new high level sensor tomorrow, unfortuanatly the temp sensor is a couple weeks out.

temp sensor reads 31.8k ohms

the high limit reads 33.3k ohms

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9 hours ago, RDspaguy said:

Then it should run the pumps, it is trying to prevent a freeze. I don't recall the exact temp that triggers the "ice" error.

Your transformer is good. 

Your sensors are not.

ok,thanks. I will start with replaceing the high limit and re-assemble the tub. If that if that fixesthe problem sweet, if not ill wait untill the new temp sensor comes in and install it. ill post the results here after. thhanks again for your help

 

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I went and put the old high limit in the tub submerged in the water. then tested all three sensors for resistance with the water temp reading 74deg

-new high limit was 29.9k ohms

-old high limit was 32.3k ohms 

- temp sensor reading 26.5k ohms 

maybe both the sensors were bad?

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18 hours ago, RDspaguy said:

That's why I recommend replacing both. 

Unfortunatly i have to wait untill the temp sensor is available. When I install the new temp sensor, if I'm still getting the watchdog error. Is it safe to assume that either the board or upper controll unit is no good?

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The upper control has nothing to do with it. Watchdog is a catch-all for indeterminate issues, usually temp or power related. The spa can tell if a single sensor is bad if it is reading outside of parameters, or if the heater is overheating but the tub is not, but if the sensors are within parameters but not accurate or the low voltage is too high or low, it doesn't know exactly what is wrong, so triggers the watchdog and shuts down for safety purposes. It basically doesn't trust the readings it is getting. This is always a power (main or low voltage), sensor, or board issue. The topside is just buttons and a display.

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1 hour ago, RDspaguy said:

The upper control has nothing to do with it. Watchdog is a catch-all for indeterminate issues, usually temp or power related. The spa can tell if a single sensor is bad if it is reading outside of parameters, or if the heater is overheating but the tub is not, but if the sensors are within parameters but not accurate or the low voltage is too high or low, it doesn't know exactly what is wrong, so triggers the watchdog and shuts down for safety purposes. It basically doesn't trust the readings it is getting. This is always a power (main or low voltage), sensor, or board issue. The topside is just buttons and a display.

Ok, so ill replace the temp sensor when they come back into stock and hope it fixes the issue it. If this fails to solve the issue, then ill re-test voltage suply to the board one last time before ordering a new one. What is the best way to test for a faulty flow sensor?

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On 6/18/2021 at 2:15 PM, RDspaguy said:

The upper control has nothing to do with it. Watchdog is a catch-all for indeterminate issues, usually temp or power related. The spa can tell if a single sensor is bad if it is reading outside of parameters, or if the heater is overheating but the tub is not, but if the sensors are within parameters but not accurate or the low voltage is too high or low, it doesn't know exactly what is wrong, so triggers the watchdog and shuts down for safety purposes. It basically doesn't trust the readings it is getting. This is always a power (main or low voltage), sensor, or board issue. The topside is just buttons and a display.

Just to touch back on the low voltage system. my transformer was producing the proper low voltage? also i have all of the lighting and audio unpluged at the rosstech controller. could that be causing and issue? 

Is It wierd that the circuit board would fail, shortly after isnalling new pumps? even tho it did sit for about 8 months before i installed them.

i just want to make sure its the board before i fork out the money for a new one. Also want to make sure that there isnt a couse that will fry the new board upon intsall.

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19 hours ago, RDspaguy said:

20201125_092312.thumb.jpg.7ef0bc4029df464220c02ba804c5eb6c.jpg

The transformer readings are a fraction high, but not so much as to cause concern. But transformers are cheaper than boards, and it is a fraction over. 

Have you checked incoming voltage to the spa? 

Voltage into the spa. 232 volts 

Black to Red 232V

B1-B2 =10.25 volts

Y1-Y2 = 14.69 volts

B1-Y1 = 2.66 volts

B1-Y2 = 12.77 volts

B2-Y1 = 12.06 volts

B2-Y2 = 2.94 volts

looks like B1-B2, and Y1-Y2 are a bit high. do you think that could cause it? Also now im only getting 232v at the spa, I'm asuming thats still adequite?

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