Old Hot Springs Spa needs electrical help

Welcome to TFP.

Sounds like the relay contacts may have welded themselves together.

If you can do board level soldering relays can often be replaced.

If you have a multimeter you can pull the board with the heater relay and use it to diagnose if the relay contacts are closed with no power to the board.

@RDspaguy may have ideas how to tackle this.

Groot said:

One of the things I did try was to measure voltage at the coil side of the relays; both relays showed around 20A with heat turned "off", all the way to heat full on.

Click to expand...

So find the connection to the rotary control knob and see if it is opening and closing its contact.

There is probably some thermostat between the rotary control knob and the relay that may have failed and is keeping the power on the heater.

Is there an electrical wiring diagram on the inside of one of the panels?

What you measured was Amps, 20 amps. A relay is like an on/off switch that has another "section" replacing the human to push the toggle up and down.

You measured the load side, but the "human side" on a relay is a coil of wire that, when it receives an energizing voltage, turns into a magnet and pulls the contacts side closed. In your case the contact side has contacts that stuck together and the relay cannot turn off when the control side voltage is removed.

Your adjustable knob is going to a controller that compares its setting with that of a sensor (or two) and when setting is lower than actual sensed temperature your controller turns on the heater relay, which is stuck in the on position.

On the control side I'm guessing on/off signal side is 12VDC, which you can measure with a meter. I wouldn't bother though, since the relay is removable I'd replace it and see if the problem is fixed. I believe it will be.

Type relay into google and select images, scroll the results and the above will go from head scratching to ah-hah!

P.S. Love the logon name, on some sites I'm Grug...

Groot said:

heat control is an old rotary typ

Click to expand...

Pics please.

Groot said:

tried replacing the control

Click to expand...

What part exactly?

Groot said:

One of the things I did try was to measure voltage at the coil side of the relays; both relays showed around 20A with heat turned "off", all the way to heat full on. So, no change when messing with the heat control knob (?).

Click to expand...

I don't understand. Did you test voltage or amps? On the coil or load? If you have 20 amps on a coil it's on fire.

Groot said:

I'm guessing older systems like mine would not have some built in program to raise the temp of a cold spa to some baseline temp?

Click to expand...

Thermostats are a range, though some do have an "off" position, so the minimum temp is set by that. It may also have freeze protection which turns on pumps in the event of freeze conditions.

ajw22 said:

Sounds like the relay contacts may have welded themselves together.

Click to expand...

Yes it does.

ajw22 said:

you can do board level soldering relays can often be replaced.

Click to expand...

Older IQ2000 systems had independent relays, then they switched to the relay board. There may not be any soldering involved.

Groot said:

my spa still uses replaceable relays so an easy fix.

Click to expand...

There ya go.

Methuselah said:

In your case the contact side has contacts that stuck together and the relay cannot turn off when the control side voltage is removed.

Click to expand...

Not necessarily, but could be. In this system, a shorted thermostat will also cause this, until the hi-limit trips from overheat. I think it's still a manual reset switch on those.

Methuselah said:

since the relay is removable I'd replace it and see if the problem is fixed. I believe it will be.

Click to expand...

If the water is 45 degrees, that thermostat and freeze protection will run it non-stop until it warms up enough.

I will also mention that electrical surges are often covered by homeowners insurance. Check with your agent.

If I am reading this correctly, what is currently happening is your 30A GFCI breaker in the spa disconnect is NOT tripping but your 50A in the main panel is.

For a 50 A to trip when a 30 in the same circuit does not, tends to point me to a defective 50 A breaker. (Of course the 30 could be defective and there could be a fault, but the most logical issue lies with the 50 at this point)

There are two things that cause a breaker to tip - magnetic and thermal. Magnetic covers the "instant" tripping that happens with a low resistance fault. Thermal happens when there is a consistent overload of current. It sound like the thermal part of your breaker is bad.

Groot said:

I don't know if that was really the cause.

Click to expand...

I don't either, but if it had come to needing a new control system I'd have tried anyway.

Groot said:

why is my 50 A house breaker tripping (10-15 minutes after turning on outside GFCI breakers).

Click to expand...

phonedave said:

For a 50 A to trip when a 30 in the same circuit does not, tends to point me to a defective 50 A breaker. (Of course the 30 could be defective and there could be a fault, but the most logical issue lies with the 50 at this point)

Click to expand...

The 50 amp also has the pumps and such fed by the 20 amp gfci, but I agree the breaker, or loose connections at the breaker, are the most likely cause.

Groot said:

old temp control

Click to expand...

Yes it is! I can only recall seeing one of those particular controllers. That was early IQ2000. Not around for long, just a stepping stone between manual thermostats and fully integrated digital. What a gem! That thermostat board can be easily repaired by any electronics/computer shop, unlike the new ones. Post a pic of the circuit board/relays, if you wouldn't mind. I'd just like to see it.

Groot said:

How on earth those screws got that loose is beyond me.

Click to expand...

Alternating current is a vibration, or creates vibration depending on how you look at it, and can loosen terminals and wear through insulation. Very common issue, which is why I mentioned it.

Groot said:

tub was made in 1997, so quarter century ago...wait, can I call it Vintage?

Click to expand...

Since it was new my 2nd year in this business, I'd appreciate it if you didn't.

Groot said:

Quick update, relays seem be ok, with coil de-energized I have no continuity across the main power in/out terminals.

Click to expand...

Coil de-energized, continuity of main power ... no such animal, "power" would fry a dmm measuring continuity.

With input (220V service) disconnected the relay OUTPUT contacts should not read 0 ohms. Easier to replace the relay if it's cheap and doesn't have to be soldered since you're already in there. Even if it's good, they don't last forever.

Since the thermostat is replaced prime suspect is the relay for over temperature. That doesn't mean a tripping breaker or gfi isn't also bad, since they usually fail if put through a lot of over current trip cycles (usual fail mode is mechanical, i.e. fail to reset or tripping at lower than rated current).

As an fyi, my gfi is lifetime warranted...

Groot said:

Well, I'm sitting here typing my update enjoying a nice cold one...beer, not spa!

While I'm happy to have my spa back, I'm a bit embarrassed how long it took to figure out. Key learning from this thread: troubleshooting in cold weather, be aware system may override heater controls to get water up to some minimal temp (mine's 50 F). Oh, and listen to advice from smart people.

When I went behind my main electrical panel to replace the 50A breaker, I had to push a few wires out of the way to get access to the screws. One of the monster gauge hot wires (from the 50A) literally slid right out of the breaker! After a few clever comments, starting with "What the ...?", I tugged on the second hot wire and that too slide right out. So yeah, after like 6 turns on one and 4 on the other tightened everything up and I'm back up and running (with the old breaker). How on earth those screws got that loose is beyond me.

So, if I were to be handing out gold stars for advice, RDGuy and Phonedave seem to have nailed it

RDGuy, happy to share that pic. The tub was made in 1997, so quarter century ago...wait, can I call it Vintage? Will see how many more miles I can get out of it...

Thanks all for your support, it is much appreciated...Cheers!

Click to expand...

You would be surprised at how often electrical connections are not torqued enough, especially bigger ones. If you are not using a torque wrench to check the standards, you should be at least using a good screwdriver.

I started using Wiha Xeno Drive recently - Insulated SlimLine Xeno Driver #2 x 100mm

They are like a combo of Flathead and Phillps drives together. They only fit screws that are combo flat/phillips, such as the ones on electrical devices - but they grab extremely well.

Sparky Channel - does a good short video on them

Looks like you had two problems. Didn't you start with an overtemp condition?

The thermostat replacement might have fixed that, but it couldn't have happened if your loosened wiring wasn't passing current.

I'd guess the breaker heating (and cooling while troubleshooting) helped loosen the terminals.

Glad you got it running but if it's not completely reassembled I'd still consider replacing that relay. It will fail, thats the nature of the beast, just a matter of when (even if it's modestly overrated, there's MTBF - mean time between failure ratings for a reason).

phonedave said:

You would be surprised at how often electrical connections are not torqued enough, especially bigger ones. If you are not using a torque wrench to check the standards, you should be at least using a good screwdriver.

I started using Wiha Xeno Drive recently - Insulated SlimLine Xeno Driver #2 x 100mm

They are like a combo of Flathead and Phillps drives together. They only fit screws that are combo flat/phillips, such as the ones on electrical devices - but they grab extremely well.

Sparky Channel -

does a good short video on them

Click to expand...

I never heard about either drive types, but was able to torque the he♧♧ out of the screws without any slipping using a Robertson (square drive) bit.

Learned something new!

@Groot, I have a 28 year old Hot Springs Grandee spa which predates IQ2000 but I have modified it to use an IQ2000 system. It has the new 6 KW heater in it instead of the original 5.5 KW heater which died a long time ago. Those 30A heater relays the IQ2000 systems use were barely sufficient to handle the loads put on it by the original 5.5 KW heater and I think the new 6 KW heaters Watkins is using are just a little too much for them and this is why I was having heater relays fail at least once per year but probably 2 times per year in a lot of years. When they fail, they sometimes fail closed so your heater will constantly be on. If just the relay sending load current to the heater fails and the your high temp shutoff thermistor has drifted out of spec, the water may get very hot in your tub before the high temp cutoff thermistor does its job and shuts off current to the heater. If both relays fail closed, nothing will stop current going through the heater.

The 30A heater relays Watkins uses in the IQ2000 are off-the-shelf relays that you can get at DigiKey or Mouser a lot cheaper than you can get from Watkins. Buy spares when you buy them because they probably will fail within a year or so if you are using them in the originally designed heater circuit.

I have eliminated the problem completely in my tub by making a modification to the heater relay circuit suggested to me by @RDspaguy. In a nutshell, what I did was put a pair of inexpensive Chinese made 50A contactor relays into the circuit to carry the load current and only used the original 30A relays to trigger the contactors. The trigger signal on the contactor relays needs to only be maybe less than 1 to at most 2 amps so the 30A relays are now only asked to handle a very small amount of current and the 50A contactors are doing all of the heavy lifting but still only handling an amount of current that is way below (like half) what they're rated to handle. As such, nothing is stressed or pushed anywhere near its rated limit so nothing burns up and fails. The best part is that the cost of the materials and parts was minimal so the only real cost was my time which wasn't too bad because it didn't take me all that long to make the modifications.

I'm now halfway through my second winter of using this modified system and so far it has worked flawlessly and without a single breakdown or hiccup. Before the mods, I probably would've burned up at least 2 or maybe 3 sets of relays in the time since I made the mods, but so far, I've not had a single breakdown on that circuit and I don't expect to anytime soon. The heater circuit is now far better engineered and far more robust than Watkins' original design/implementation.

I took a lot of photos of how I did the modifications and have been intending to post them here but just haven't gotten around to it. If people are interested to know what I did and how I made these modifications to the IQ2000 heater circuit, I will post the information.