I have been following the various threads look for info, but nothing has jumped out at me yet. Here's my equipment-

Circa '95 Hot Springs Classic (the dog dish model)
220v to main pump and to a two element heater box
110v to circ pump, Watkins Silentflo 5000
(I believe) all original piping/plumbing

Situation- with the thermostat on low or off, and no heat coming from heater, the tub will run anytime I ask it to. Lights, circ pump, main pump are all energized. If I turn it up and hear the "click", everything will run for between 3 and 8 minutes and then will trip the little red reset button marked "heater" on the control box (high temp trip?). Now nothing is working. I can reset, but it will trip right away. I let it all cool down, come back and get 3 to 8 minutes with everything working and hot water coming into the tub through the return on the inside wall (I can feel the heat on my hand).

I thought this might be a circulation problem and the heater overheating- the box does get hot to the touch during the few minutes after it powers up and before it trips. I removed all three of the canister type filters to improve flow in case they were clogged- no help. I also get full jets. I have not disconnected the inlet or outlet side of the circ pump, as I can see bubbles moving and hear flow in the tubing. Not sure how much should be passing through- so maybe this is the culprit. What is the best way to check for appropriate flow through the circ or through the heater or through both? Any other ideas?

Also- there is a port on the heater box where a temp probe is plugged in. It doesn't seem to matter whether it is in the hole or not. There are two other temp probes coming from the control box and not plugged into anything, just laying in a dry area under the control box.


Dave, Atlanta

It sounds like the temp probes have been pulled loose.....and perhaps the spa high-limit is inserted in the heater...(or the circ pump flow is indeed too low, or maybe even the heater high limit has malfunctioned)

The high-limits are easy to recognize... the sensing bulbs will make it easy to identify which one goes where...

The smallest bulb, in both length and diameter is the heater high limit... it should be inserted fully into the drywell of the heaterbody.

The fattest bulb belongs to the thermostat, it should be inserted (along with spa-high limit, the long, thin sensing bulb) into a drywell that is either located in the control box, or on the base of the tub.

You should be able detect water flow from the circ pump simply by feeling it return to the spa. The return fitting is near the light in a 1994...(yours cannot be any newer than a 1994) just feel inside the spa for circ pump flow... i'm guessing the circ pump is bad... just guessing, though

Swine- you hit it on the head I think. I disconnected the outflow side of the pump and fired up the circ motor- it spins but wasn't pushing water, at least not enough to feel pressure on my finger. Sounds like the impeller or something has gone out. Do they make a rebuild kit for these? This could be a low cost fix. Thanks!!