Panel blinks OH and stops

[VS1957]

I have an older model Northwest Spa.

The model is a 620D 240V. They use Balboa Instruments for the internal components.

The tub has been working fine for several years. Now when I turn the tub on it will run for 1 to 2 hours but then shuts off with an "OH" reading? If i press the temp button it will start again and run for another hour, but then shuts off with the "OH" reading.

Any idea's on what the problem is?

[Mary]

If the spa has a temperature display on the top side panel verify that the temperature on the display matches the actual water temperature in the spa using a thermometer. Have you gotten any other messages on the control panel like FLO or any others? What is the actual water temperature?

[VS1957]

The temp on the display is correct. It matches the water temp.

It is not an overheating problem because I keep my tub at 100 or below. I replaced the heating element (it had a small leak at the terminal)but still comes up with the OH display.

It does not seem to matter what the water temp is. The tub has been off for 2 days and the water temp is at 60. When I turn the tub on, it will run for 1 to 2 hours and heat the water up 15 degrees, then shuts down with the OH reading? If I press the temp arrow up it will start again and run for a while but keeps shutting back down with the OH display. I have had no other display error other then OH?

[Mary]

I don't think the heating element would be causing this. More likely a temperature sensor problem. After the spa pump has been running for a while is the water flow coming out of the jets the same as when you first turned it on? Are there any slice valves on the spa, if so make sure they are all the way open and not slightly closed.

[obie]

I have the same issue. I replaced the sensor and checked the slice valves and they are opened, could it be the circut board (Mother Board) ?

[MaryH]

If the filter is not restricting water flow and the sensors are new then yes it could be the circuit board causing this. We try and go through every possible senario before replacing the board but sometimes it is necessary. Is the water in the spa the same temperature as what you have it set at and maintaining this temp?

[obie]

Yes - It gets to the temp I set it at, but when the OH reading is displayed and blinks it stops heating and working. When I push the temp down button it starts to work again for an hour or two.

[obie]

Yes, the temp is the same. When I get the OH reading and the temp goes down from not running the temp is correct when I push the down temp button and the temp reading is displayed. I'm pretty sure the OH reading will come on in @ 2 hours if the pumps are running or not. Is there anything else I can check before replacing the circuit board?

[MaryH]

The sensor you replaced, was that the high limit? Is it the one on the heater? Is the heater coming on when the pump is not running? Unless you have a small circulation pump the heater should never come on without the pump running. If it is and you don't have a small circulation pump that runs 24 hours then it very well may be the circuit board.

[obie]

The sensor I replaced was the (Balboa, High limit & Temperature sensors). I set the temp at @ 92 - when it hits that temp it maintains it then eventually the OH reading comes on. The unit ( Suntek ) is around 14 years old should I replace the circuit board or the whole Balboa unit. It has the origional heating unit?