Need some quick education!

[r5ran]

Hi, I have owned a relatively trouble free 2008 Hot Springs Vanguard since new, but now have been fighting a very intermittent problem for over a year now (I will address this actual issue in another post soon). While I know the basics of how a hot tub works, I do not know the specifics of what each component sensor does and the proper sequence of everything for proper operation.

As a now retired mainframe computer tech, with all their attached peripherals (large production printers, check sorters, disk libraries, etc...) fixing complicated electro-mechanical monsters was my daily job. However, we were educated on how these things actually worked, so you could troubleshoot problems systematically. I truly felt, that if I understand how something is suppose to work, I can figure out the problem when it doesn't. My issue though, is I have not found some type of educational video or article that actually explains the detailed and exact process and role of each hot tub component or sensor, and what happens if their is a failure of each. Sure I have read some schematics and articles/videos that helps you troubleshoot the basics, or advice from forums on what component to replace, but nothing that explains the big picture and why this component is likely the fix.

So, is their any type of educational article or video some one can suggest that would give me this basic education and understanding I need? While any suggestion is appreciated, something related to what HS uses, with the circulation pump would be best.

Thank you in advance, Randy 

[imlost]

Randy, 

I'm not aware of any specific source of information that will help you. I'd just ask specific questions regarding the problems you're having. Also, it always helps to post pictures of your system. 

[RDspaguy]

Watkins, the folks that make hot springs, use invensys controls and their designs are proprietary and protected by patent. You will not ever get what you are looking for unless you work at or maybe hack in to invensys. 

Just describe your issue and post the pics, we'll see what we can do.

[r5ran]

I guess by the lack of other responses, I suspect you are probably right, and their is not much out there in the way of basic documentation. While I realize HS does things a bit differently, I'm not asking for a complete electrical schematic of the system board, I would just like some theory and basic operational  points.

I know it's a very simple system that many other companies use. A small pump pump runs continuously, drawing water through a filter, then into a thermostatically controlled heating element, which then delivers the clean and heated water back into the tub itself. There are only a few sensors or switches that monitor this process, a high-limit thermistor, a control thermistor and a pressure switch ( their may be more?). If I knew what each of these actually does, and their role in the sequence of operation, that alone would be helpful.  I know the high limit thermistor monitors the temperature of the heating element, and shuts off to protect it from overheating, but not sure what the other components role are in the big scheme of things.

While their seems to not be much documentation on this, I am sure their are many knowledgeable and  experienced people out there, (like yourself) that know this info very well. A few simple paragraphs would enlighten myself and many others.

BTW- I may have diagnosed my intermittent issue I have been fighting and mentioned earlier, and am putting together a post on that soon.

Thank you, Randy

[RDspaguy]

On 1/23/2022 at 8:20 AM, r5ran said:

know the high limit thermistor monitors the temperature of the heating element, and shuts off to protect it from overheating,

The computer compares thermistor readings. A discrepancy of a few hundred ohms (less than one degree) can trigger errors.

On 1/23/2022 at 8:20 AM, r5ran said:

but not sure what the other components role are in the big scheme of things.

Pressure switch indicates low flow issues and shuts off certain components. This can be faulty parts or flow restriction (dirty filter for example). 

Since the placement of the thermistors is at opposite ends of the heater, and will therefore trigger errors from low flow even without a pressure/flow switch due to temperature discrepancy, this is bypassed in some watkins systems (and other) systems. Never bypass a manufacturer installed safety device.

High temp readings (3 degrees above set temp) will turn off the circ pump.

Watkins are "smart", but not user friendly in that every error gives the same stupid flashing light. Other systems show specific errors on the display, which makes them much easier to troubleshoot.

There are 3 LED indicators on the board, "lim ok", "control unplugged", and "htr on". These help to narrow things down.

Hope that helps.

[r5ran]

Yes, it does help. Thanks for you efforts.

I agree about the stupid diagnostics and the simple flashing red light. I wish they had something that gave you a bit more info, but this is old tech nowadays. I think when they updated this model mid-2009, they did add some real diagnostics and error codes.

Reminds me of my furnace (hot water boiler) I just replaced in my home. The new one is the exact same model as the 30 year model it replaced. Even looks identical on the exterior. Only real difference is the new electronics board has a complete set of sequential lights for each step of the ignition process , and an LED screen for error codes. So much easier to diagnose. But that's progress. 

Thanks again, Randy