OH flashing on Control Panel

Old 12-30-07, 12:46 PM
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OH flashing on Control Panel

I have a situation where my spa has OH flashing on Control Panel.

This happened a few times about a year ago but stopped when I replaced my filter.

Recently my Main 2 speed pump quit and I replaced it. After replacing it the spa worked perfectly for about a week then I started to find that it had shut down and was flashing OH. Did some searches around the internet and in other forums and found that this is usually caused by either a faulty thermostat, Overlimit Sensor or main PC Board but none of the other discussions were close enough to my symptoms to help me focus in on a cause.

Here are my facts: Coleman 107 with Balboa controls. Just put in new filter and have tried running both with and without filter in place.

When come out and find OH flashing:

1. If turn power off and on at main breaker - spa starts up -heater starts without pump running - heater indicator light does not come on. Can tell heater is on by sizzling sound of boiling water in heater. Pretty quick goes to OH and shuts down.

2. If hit pump button and spa has not cooled off nothing happens.

3. If hit pump button and spa has cooled off pump turns on and correct temp shows and heater comes on and begins bring spa up to temp. Spa then works fine for awhile ie: comes up to set temp, responds appropriately to raising and lowering temp setting and cycles on and off to maintain temp for awhile but then eventually goes back into OH condition.

So -

Thermostat seems to be working ie: correct water temperature shows on display as verified by floating thermometer.

OH Sensor seems to be working as spa shuts down when temp gets too high.

Pressure switch? - Not really sure should it prevent heater from coming on as described in #1 above?

Would appreciate any help in troubleshooting!


Old 12-30-07, 01:41 PM
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Here are the causes for the "OH"

1 Overheat protection may occur if the pump is set to operate for extended periods.
2 In extremely hot weather, check for proper cabinet ventilation.
3 When the hot tub is in a filter cycle, make sure P1 low-speed is on.
4 Check slice valves/make sure that they are open.
5 Check for blockage in the filter cartridge, skimmer basket and pump intake fittings.
6 Check the alignment of the heater element in the heater housing to make sure it is straight a not contacting the sides.
7 Make sure the temperature sensor is installed properly.

One of these should be your problem...
Old 01-10-08, 10:13 PM
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OH flashing on control panel

What you are describing is dry firing of your heater. This is probably caused by a bad pressure switch. The heater should never fire when the pump isn't running the heater element will melt down if the hi limit doesn't catch it quick enough. I would start with replacing the heater pressure switch-good luck

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