Hot tub overheating

[Jimmie]

Have a hot tub that overheats to the point of blistering the insulating
cover. Temp sensors have been replaced, Electronics package has been
replaced ,accuracy of thermometer/thermostat verified. Disconnected heating
element and it still overheats. Cools down when it is completely shut
off(big disconnect on the wall) so source of heat is internal to the hot
tub. Doesnt make sense to me that the water is being heated through pumping
but I guess this is the only thing left. Any ideas would be greatly
appreciated.

 

[Guest]

Doesnt make sense to me that the water is being heated through pumping
but I guess this is the only thing left. Any ideas would be greatly
appreciated.

There are spas style tubs that are kept warm solely by the heat gained
from the pumping system. Sounds like a problem with the pump.

 

[Tim Perry]

There are spas style tubs that are kept warm solely by the heat gained
from the pumping system. Sounds like a problem with the pump.

got any referances/links to such a system?


used a clamp on ammeter to measure the current that the motor uses. measure
right at the motor. then measure the total amount of current supplied to
the hot tub at the breaker panel. if the current is much higher at the
panel there is a second heater hidden away somewhere that you haven't
located yet.

(test should be performed by qualified personnel)

 

[Jimmie]

Or a valve somewhere in the system almost closed.

Motor current is fine, no hidden heaters, no water flow restrictions. trying
to contact the manufacturer.

 

[Jim Douglas]

Are you sure Michael Meyers is not somehow involved in this problem. Sorry,
just saw the original Halloween!

 

[Bob]

If it is a Jacuzzi pump, they use a water jacket around the motor to
take advantage of the motor waste heat. Saves on the heating bill in
the winter, but unfortunately they can overheat the water if covetred
in a hot area during the summer. I am inCalifornia and it happens to
me all summer. The solution is to leave it uncovered, but make a
screen for the top so that it does not get crud in it.

 

[daestrom]

Motor current is fine, no hidden heaters, no water flow restrictions. trying
to contact the manufacturer.

Take a look for the rating of the pump/motor unit. That much power is being
put into the water. If a 1 hp pump/motor is 85% efficient, that means 0.85
hp is being delivered to the water in the form of pressure/flow. But in a
system such as a hot tub, all the pressure/flow energy of the water is
dissipated in the turbulance and is converted to heat.

So that 0.85 hp is just a 634 watt 'heater'. Of course, if you have a
larger pump/motor, it is really just a larger 'heater'. Usually this amount
of energy can only warm the tub so much, then ambient heat losses take over.
But if it's well insulated and covered....

daestrom

 

[Jimmie]

Have a hot tub that overheats to the point of blistering the insulating
cover. Temp sensors have been replaced, Electronics package has been
replaced ,accuracy of thermometer/thermostat verified. Disconnected heating
element and it still overheats. Cools down when it is completely shut
off(big disconnect on the wall) so source of heat is internal to the hot
tub. Doesnt make sense to me that the water is being heated through pumping
but I guess this is the only thing left. Any ideas would be greatly
appreciated.

Fixed my overheating problem even though I am still not absolutely sure of
the cause. Turned on the air all the time. Bubbles seem to help cool it and
the temp never rises more than 1 degree above the T'stat setting.