Spa heater issue

[SorryImaNewb123]

Hello Everyone,

Following a power outage, our hot tubs pump died It was not working for about 2-3 months until I ordered and installed a new pump. Everything works fine except something is up with heater now.

• The heater works when you first turn on the power to spa while is does the startup filter process. That startup process lasts about 20 mins (heater light is solid and water starts getting warm). But once that filter process is done, heater light goes off and water no longer stays warm.
• Additionally, the display reads 32 degrees. No error codes. I can press increase/decrease and shows temp increase/decreasing on the display, but the temp just immediately goes back to 32 and stays there no matter what. Before all this happened, when you press to increase the temp past a certain temperature I would hear a little click and the water would start heating. but now even if I increase to 104, it just immediately goes back to 32 degrees, no click, no heat.

I googled a bit and found that testing the heaters resistance with an ohms meter is a good start. So I powered off the spa and disconnected the heater cables from the gecko s class 2001 electrical board. The ohm reading on the heater assembly was very inconsistent. It jumped from various high numbers to lower numbers and back to higher numbers, then eventually goes to 0 after about 10-15 seconds. So not sure what this means as I don't know much about electrical.

Could the fact that I left water sitting in the hot tub for 2-3 months before replacing pump mess up the heating element? Maybe the power outage messed it up and I just didn't know until I got the pump working again? Something else?

 

[mas985]

Electrical heating elements behave a bit like an inductor so when you do a resistance measurement on it, it will read high and then eventually drop in resistance. However, it shouldn't drop much below about 5 ohms. What was the minimum resistance that it was reading? I am assuming this is a 240v heating connection correct? What size breaker is the heater connected to?

The issue could be the temperature sensor if the readout is always reading 32F.

 

[RDspaguy]

The fact that it started with a power outage that actually damaged a pump does not bode well for your control system. Add on an impossible sensor reading with no errors and I'm guessing circuit board, which means new control system.
First, test the sensor. Place it in a glass of cold water and take a resistance reading, then the same in hot water. The reading will be in the 10s of thousands of ohms, so set your meter accordingly. Post results.
A heater should give a steady ohm reading, I've never seen one decrease over time. It may jump a bit as you are making contact, but should be steady once the leads are touching. It should be between 10 and 16 ohms depending on the kw of the heater. 0 ohms is a dead short and would trip your breaker if turned on, as well as fry the relay. Test voltage at the heater terminals (one terminal to the other) when it's calling for heat. Post results.

 

[SorryImaNewb123]

Just an update that I ordered a replacement temp sensor and that resolved the issue! I'm very relieved it wasn't the circuit board as that would have been a lot of $$$.

I have 2 more questions that are somewhat related. Any help to try to prevent this from happening again would be appreciated.

1) What am I supposed to do with the thick metal ground cable that connected to my pump? It's just sticking out of the pump but not connecting to anything. It was the same on the pump that died during the power outage as well. Is it supposed to be just sticking out connected to nothing???

2) Is there anything else that could have prevented the power outage we had from killing the motor? The breaker that our hot tub connects to has a built in GFCI protected breaker similar to this one....

 

[wireform]

The copper wire is your bonding wire and should be connected where the other equipment on the pad is bonded to.
The gfci breaker isn't designed to protect the motor from a power outage but more about protection for anything powered that can be in contact with water.