IQ 2020 Control Board Question

[John Moore]

Can anybody tell me what the constant red LED on my control board means? The LED is located next to the marking D21 and below marking F51. The other LED's that are lit are Limit OK which is constant green and PWR ON which is flashing green. On the outside of the tub the Hotsprings Logo lights are both flashing too.

I have checked the and fitted the following;

1. New filter.

2. New High Limit Sensor.

3. Checked circ pump for air lock - all clear.

4. Tried new circ pump but to no avail.

I want to confirm these LED's before I start investigating possible blockage.

Cheers

[imlost]

From my research, I've not been able to find info on what the D21 LED is for. It seems that steady red is normal function, though. 

My money is on the pressure switch (or flow switch) needing replacing.

[John Moore]

Many thanks for your reply. I shall investigate that further.

[RDspaguy]

Post pics of circuit board.

Many IQ2020 systems do not use a pressure/flow switch. The flow switch connection on the board may just have a jumper on it. If not, you can jumper that for testing. If it works while jumpered it is an open switch, which can be a bad switch, a chewed wire or loose connection, or a flow issue.

I recommend replacing both thermistors at once. You can test them with an ohm meter in the 20k ohm range.

[John Moore]

Many thanks. I will put a jumper across the flow switch connectors to see if it is the flow switch that's open. When you say thermistors, do you mean the Control Sensor and High Limit Sensor as I replaced both of these as the High Limit Sensor was defective?

[RDspaguy]

Yes, thermistors are sensors. 

[pdelahaye]

I've no idea how much these IQ2020 PCB's have changed over the years, but on my 2009, when the red LED is lit, it's indicating the board is calling for the Heater to be on.  

It required the pressure switch to either be working or bypassed to make the red light come on.

 

There are some pictures here of my IQ2020 PCB for comparison.  I don't have a Power LED, only the limit one, so it sounds like it might have changed a bit.

[RDspaguy]

The power led is on the control panel, not the board. They have not changed much visually, but some systems are obsolete and not compatible with new replacement relay boards, which have visually changed several times.

[Elad]

I have a similar issue with red light by D21 and flashing green power on indicator light on my IQ 2020. The 30 switch on my breaker usually trips randomly in the middle of the night every 1-2 days as well. 
 

any idea what might be going on? 

Photo here

[Spa Owner]

Did you ever resolve this issue ? 

I have the same issue - steady red light by D21 and the only other light is steady green voltage light. Checked power through all wired connections, and I get the right voltage.

The control panel wasn't getting any power, so i thought that it was broken. I replaced it with a new one but even that did not get any power. Is my board itself gone?

[pengu222]

Did anyone find the issue ? I have the same problem