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Hot Spring Vista (2004) Slow to heat/trouble maintaining heat


Empereol

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Every now and then I see that my Vista's green "Ready" light is off. When I check the temperature of the water, it's usually a few degrees below what it is set to (ex: Spa set to 100℃ but that water will be at 97℃). Adjusting the temperature down, the "Ready" light will come back on due to it now being in "ready" range and you can hear the heater relay click off when you set the temperature to what the current water temperature. Adjusting the temperature back up, you can hear the heater relay click on - I also verified the "Heater ON" light is illuminated on the circuit board. Even when the "Ready" light is illuminated for a steady period of time, the temperature will be at the low end of the acceptable ±2℃ range.

So far, I have tried the following:

  1. Checked water flow
    1. I can see a steady stream of bubbles from the floor drain.
    2. Cleaned ceramic filters with filter cleaner/dishwasher. They appear clean and we have not used the spa much this year.
    3. Swapped filter positions to test multiple filters on the circulation/heater line. 
    4. Pumped water from a hose directly into the circulation/heater line to clear any potential air lock that may have been present though the pressure switch never indicated a problem here as well as I mentioned in 1.1. I could see a steady stream of bubbles from the circulation line.
  2. Tested voltage to the heater - Correctly reads ~240V when "Heater ON" illuminated
  3. Tested resistance of the heater - Reads ~14.5Ω, which I believe is within the acceptable range. I've read it can be between 9-14 but sometimes as high as 20.
  4. The high limit and control thermistor are both newish and were replaced when I was diagnosing a different problem back in March of 2021.

I had an issue earlier this year with my circulation pump was malfunctioning when the water was of a higher temperature (>85℃). The circulation pump would cycle on and off every ~30ish seconds. When the pump would shut off, you would hear a boiling/steam sound. I would imagine that the heater took a bit of a beating during that time period.

Because of that issue, I'm thinking that the heater is starting to go but I wanted to see if anyone else has any thoughts?

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The circulation pump will cycle on and off until good pressure or flow is achieved. This can be due to restricted flow (dirty filter) or air (or debris) in the pump intake, but can also be due to a faulty pressure switch or flow switch. It can also happen if your circ pump is working intermittently, or if your heater is causing a flow restriction. 

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On 12/16/2021 at 12:08 PM, RDspaguy said:

Remove filters.

Post pic of circuit board when ready light is off. 

  1. Removed filters - no change
  2. Board pics while ready light is off: https://imgur.com/a/gE3hMEf

 

On 12/19/2021 at 10:40 AM, imlost said:

The circulation pump will cycle on and off until good pressure or flow is achieved. This can be due to restricted flow (dirty filter) or air (or debris) in the pump intake, but can also be due to a faulty pressure switch or flow switch. It can also happen if your circ pump is working intermittently, or if your heater is causing a flow restriction. 

With help from this forum back earlier in this year, we were able to diagnose that the circ pump was likely faulty and overheating causing it to cycle on and off. I replaced the circ pump back then and it resolved that particular issue.

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It happened again so I was able to test before resetting the breaker...

While the HTR ON light is illuminated:

  1. Probing black to white: ~240V
  2. Probing black to green: ~120V
  3. Probing white to green: ~120V

After resetting the breaker, there was no visible change to the board indicators/lights and voltage read the same as above.

I did notice that the ground crimp connector was a little loose.

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I checked the mains voltage coming to the spa (at the spa terminals) and it's a 3 wire cable (black, red, white) and neutral to ground was reading 120V. My understanding is that neutral to ground should read 0V. I don't know why that would be the cause of the issue either way since cycling power to the spa resolves the issue for a while. Not to mention that it's been wired that way for a while - at the very least for almost a year as I had my home's service panel replaced earlier this year.

So I'm completely stumped by this... This is my thinking so far:

  1. COULD be the control board since cycling power resolves the issue for some time
  2. NOT LIKELY the control board since it is supplying the heater 240V
  3. NOT LIKELY a flow issue...
    1. Control board not indicating a problem with pressure switch/flow
    2. Removing filters does not resolve problem 
    3. Can visibly see circulation at all times
    4. Can hear/feel circulation pump running
  4. COULD be the heater because it's receiving 240V
  5. NOT LIKELY the heater because it's resistance is 14Ω... Which I think is appropriate... Although this I'm still unsure about because I'm finding different information all over... Some say the heater should read around 9Ω... Others say between 9-20Ω. Only consistent info is if it's 0 or greater than 20, it's definitely shot. Maybe as it runs for a while and the components heat up the resistance rises too high?

So here are things that might be tangentially related...

  1. Replaced my home's service earlier this year
  2. Replaced the spa's circulation pump earlier this year
  3. Replaced spa cover ~4 months ago
  4. Last spa dump/refill was sometime in October... Used Ahh-Some spa cleaner for the first time

 

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Power is supplied by two breakers. Post a pic of the wiring diagram and the breakers.

Remove the small circuit board and check the back. Post a pic.

You say the heater has the right resistance (ohms) and is getting 240v black to white. If that's the case, it's heating. 

If the circ pump is turning off it's probably the pump itself. Test the circ pump voltage when it stops.

The voltage from neutral to ground sounds like a bad breaker, but could be something else. Do you have 120v red to white and black to white?1792933695_Screenshot_20211222-173957_SamsungInternet.thumb.jpg.ba282f2bcb1a834519145f9cabd5fa9b.jpg

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I'd like to see the connections at your breaker panel, and also your sub-panel. Your main panel should have a single, 50 amp double-pole breaker with 4 wires going to the sub panel. Your sub panel should have 2 gfci double-pole breakers (not single pole) - 20 and 30 amp. If your problems started when your panel was replaced, I'm betting something was wired incorrectly. Post pics.

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Thanks for your ideas and advice so far. I was only able to take another look at it just now due to the chaos of the holidays... By the way, happy holidays!

I was able to take the relay board off to inspect the back and it appears I have 2 blown contacts - 1 going to one relay and 1 to another relay. I've updated the imgur album with the additional photos (blown contacts, wiring diagram, etc...): https://imgur.com/a/gE3hMEf

I imagine it's likely this is the cause of the original issue and will get that relay board replaced. However, it still seems very strange that the output voltage to the heater was still 240 V but the spa is staying consistently 2-4℃ below the set temperature.

But for additional clarity and to definitely rule some of the other things out:

  • The circ pump had consistent 120 V while the issue was present.
  • As for the neutral-to-ground issue, turns out the white was marked/tapped off black at the breaker/sub-panel but not at the spa... So it wasn't a neutral but was hot. So the voltage to ground is correct. 
On 12/24/2021 at 9:51 AM, imlost said:

I'd like to see the connections at your breaker panel, and also your sub-panel. Your main panel should have a single, 50 amp double-pole breaker with 4 wires going to the sub panel. Your sub panel should have 2 gfci double-pole breakers (not single pole) - 20 and 30 amp. If your problems started when your panel was replaced, I'm betting something was wired incorrectly. Post pics.

The problem didn't occur when the panel we replaced but only now. You are also correct with how the panel/sub-panel is laid out.

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Any reason why you think it isn't wired correctly? Keep in mind, the white wire that is connected to terminal slot 3, is not a neutral but a hot wire. It was only taped/marked at the subpanel.

The spa was installed and used for over a decade, so I would think it was wired correctly. I wasn't the owner during the install but for the past 5 years, the wiring from the sub-panel to the spa has not changed. And has functioned fine during those years with the exception of some components failing presumably to age since many were the original parts.

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Ah, I see now. 

I don't work with this brand of breaker much, but most gfci breakers have the neutral connection in between or behind the hot connections. If that is the case, your breakers are not wired properly. It also appears that you have #12 wire for the 20 amp and the 30 amp circuit, but it's hard to tell in a picture. The 30 amp needs a #10 wire.

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You'll need the Watkins 77119 replacement board. Be careful, it's wired a bit differently than your current board. Also, be sure to notch the aluminum frame around the contact that has clear/orange tape over it. Don't remove that tape.

If you main board has never been replaced, leave the jumper on 18v (not 12v).

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On 12/29/2021 at 6:24 AM, imlost said:

You'll need the Watkins 77119 replacement board. Be careful, it's wired a bit differently than your current board. Also, be sure to notch the aluminum frame around the contact that has clear/orange tape over it. Don't remove that tape.

If you main board has never been replaced, leave the jumper on 18v (not 12v).

Thanks. I'll post a follow up when I have the new board installed.

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  • 5 weeks later...
  • 3 months later...

Follow up: The replaced heater relay board died.

After replacing the heater relay board, the spa appeared to be functioning correctly. However, when the spa was at temperature you could hear the relays click on and off several times per minute. I'm assuming that a few months of constantly switching on and off eventually killed it.

I have since replaced the entire IQ2020 pack (main board, heater relay board, new thermistors) and everything is again functioning correctly - this time the relays are not constantly switching on/off. 

 

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