disk tstat on hot tub

[junkhound]

Asking here as someone may know hot tub details.

GD filled with hot water from gas WH and tripped the bimetal disk protection t-stat. I was able to reset OK, etc.

However, the Genesee Hot SPrings hot tub has a small 3/8 dia vinyl tube connecting the overtemp control box and 'somethng'
It has hardened with age and proke off the nipple to the contorl box. Sealed bothends with wooden dowel plug and silicone, after resetting the overtem tstat hot tub heats, draws 21.4A, etc. etc.

What I dont know or can find out on the internet is what that hose does or controls. No observed differnece in operation with it plugged. When broken, both ends squirted water at just gravity pressure.

Annehave any idea what that controls? The end at the overtemp tstat connects to the water flow thru the heater, no idea where the other end goes, it dissapears nto the tub insulation.

 

[ptonsparky]

In the distant past when I occasionally worked on HTs those tubes went to pressure activated switches. The PB being available to tub occupants.

 

[kwired]

i never seen an overtemp sensor that didn't have sensing device in the main flow off the heater. You make it sound like there is a vinyl tube going to an overtemp sensor of some kind?

 

[junkhound]

The overtemp sensor is a klixon type bimetal switch mounted against the calrod enclosure. The 1/2" vinyl tube is something not directly related to the overtemp sensor, jsut in the same physical general location. , All I can think of it is some kind of 'burp' tube for trapped air bubbles in the circulating flow, but it goes DOWN from the overtemp module.

 

[Jraef]

The overtemp sensor is a klixon type bimetal switch mounted against the calrod enclosure. The 1/2" vinyl tube is something not directly related to the overtemp sensor, jsut in the same physical general location. , All I can think of it is some kind of 'burp' tube for trapped air bubbles in the circulating flow, but it goes DOWN from the overtemp module.

As Tom said, it was common in early days, before reliably safe LV control panels, to use pneumatic tube switches to turn things on and off in the hot tub. You usually had one to toggle the main pump on and off, two for the temperature (up and down), one for the light (if any) and possibly one for the air valve to get bubbles. Sometimes the heater was on a thermostat outside, the bubbles were on a manual valve and there was no light, so all you had was one button that toggled the pump on or off.

They still sell these systems to the nervous nellies, but most now just come with a little control panel that works at 12VDC.