Thermostat problems..........

[tjcarothers]

G'Day All,
I need some help diagnosing a problem, please.

We have a Tiger River (Hot Springs) spa, older model. It is not big, but does great for its size for us. We are having temp problems, though. One Day, I will go out to check things, and the temp will be at 101 deg (my wife likes it warm) just like the thermostat setting says. It will go that way for a week or two. Then suddenly, I will find it at 110 or above. I turn down the thermostat, let it cool, then turn it back up 'til I here it turn the heater on. It will be set at about 85 deg on the dial. It will be there for a couple of weeks, then I will find it at 85 deg (burr!!) and I turn it back up and start all over again.

So, I am asking for help to diagnose the problem without replacing everything 'til I find it. What steps can I take to isolate it? How can I check the temp sensor? How would I determine the circuit board voltages and switching?

Any help would be appreciated.

TJ.

 

[Alfred Beachport]

The temperature sensor is probably a heat-sensitive resistor.

I would start by checking the wires going to the sensor itself, and making sure that all of the contacts are good. If it connects to the circuit board with solder joints, I'd touch those up. If screw terminals, clean them. If it's a plug connector, pull it and spray it with contact cleaner (the DeOxit sold at Radio Shack is excellent).

It's not a bad idea to go through the electronics of an older spa and just make sure that all the wire connections are clean and solid. The metal in them oxidizes, and that oxidation increases the resistance.

An intermittent problem like this does suggest a sketchy connection.

Also, if the temperature control itself is a simple potentiometer, it may be dirty or damaged. I was surprised to discover that Raypak used a standard non-sealed pot for the temperature control on my heater.

 

[spishex]

I've had problems with the potentiometer style controls on Tiger River spas getting corroded (pic of control in question below). There are two boards on this controller, either could be the issue. You might also need the new sensor.

Post your progress. If you need parts for it, Backyardplus.com has served me well and he'll help you out with diagrams and so on.