ACC Spa Controller – PSOL and PSOH Errors – What are they and how do I fix them?


PSOL and PSOH Errors are common on the ACC Spa Packs – especially during initial setup and testing. Firstly, whilst it is frustrating for sure, this is not something to worry about; usually there is an easy fix. In this article, I will explore the common reasons for these errors and explain how to fix them.

What are PSOL and PSOH Errors?


On the topside controller (the keypad that controls your jets) you will see these error messages if there is a problem with the unit. Basically, PSOL means Pressure Switch On Low and PSOH means Pressure Switch on High. In short, usually this is due to a water flow problem.


The unit is equipped with these pressure switches so that it can sense when water is moving through the unit. What the unit wants to avoid is turning the heater on and running it dry or “kittling” the water if there is in fact water flowing through the unit.


These switches or sensors are there to protect the heater and stop the unit overheating.


Why do I get the PSOL and PSOH Errors?


The short answer to this is that the controller cannot sense any water flowing through the unit. This is when the errors occur. You can try pressing the “mode” key to clear the error, but usually, you will need to do a little more fault finding first.

PS You will get this error if there is no water in the tub and you try to power up the controller too.


What generally are not causes of PSOL and PSOH Errors?


As a general rule, these are not hardware problems. Generally, it is not the physical hardware that is at fault. This is especially true of this is a new hot tub or a new controller. The chances of the pump or the sensors being faulty is very slim indeed.


Common Causes of the PSOL and PSOH Errors and how to fix them


Air Lock


You have just filled the tub and are testing – if this is the case, then the chances are that you have an air lock. This is especially true if you have just filled directly into the hot tub for the first time and you have not filled through the filter or the skimmer – whichever is at the highest point.


You need to let the air out of the system. An easy way to check if you have an air lock is turn on the pump and see if you can see any “action” in the water. Try turning it to high speed – you should see lots of flow in the water even on low speed.


Check the pump is running by putting your hand being the pump – you will feel the fan running – although you can usually hear the pump running. If it is running and no “action” in the tub, you have an air lock.


I have an article here on air locks and how to resolve them.


(side note here – if the pump is getting very hot quickly then you have not wired the unit up for 230V and you are putting way too much current through the pump at 115V stop immediately and check the setup.)


Gate Valves Closed


This may sound an obvious one, but you must have both the gate valves open on the system to allow for the water to flow. Double check that they are both open before you turn on the pump.


Obvious, I know, but it does happen, make sure they are open.


Filter Installed the Wrong Way Around


This one is another common error. The filter, when you install it needs to be installed the correct way around. The filter housing will have an arrow on and that arrow should be pointing in the direction of the water flow. If it is not, you need to cut it out and change it around.


The filter has a flow valve inside that will open when there is too much pressure, if the filter is in the wrong way around, then this will not happen, it can’t open and will cause flow problems that can cause this error.


Testing without any Physical Jets in the System


This is one that you may think would not be a problem, but in fact it is. If you are trying to test the system and you have no physical jets screwed into your plumbing, then you will get the PSOL or PSOH errors.


The reason for this is that the sensors require there to be back pressure on the jets. If there are no jets, then no back pressure is created and the water just flows out, unrestricted. This causes the error as the controller cannot tell if there is water flow or not, so to prevent overheating, it shuts down the system.


Fit your jets, they just screw in, then you will be able to clear the error and run the system.


Suction Drain Blockage


Out of all of them, this is the least likely to be the problem. However, if there is a blockage on your suction line, then you will get the PSOL or PSOH errors. Likewise, if all the jets are closed and there is too much pressure – but again, very unlikely.




Usually, if it is not something simple like a gate valve inadvertently closed, then these PSOL and PSOH errors tend to arise from air locks after you have filled the system. Follow the steps in my air lock article and you will be able to clear it. If all else fails, empty the water, and refill slowly through the skimmer.


Hope that helps


Happy “error free” hot tubbin’



Can I Help You?

If I can help you in any way I would love to hear from you. You can get in touch using the form below.

Thanks - Andi


Hi, Andi here. I own and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Today, I've helped over 1000 DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi

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