Aqua pro model 50HC heater

[Jpollock]

We bought a house last year with an above ground pool. It worked fine last year but the heater doesn't seem to want to work this spring. It's showing "E3" in the display. The owners manual shows an error code EE3 which means low pressure. Could that be the issue? If so, what causes it and how do I fix it?
thanks

 

[danpik]

A quick online search shows that that is indeed a low pressure fault. Is the filter clean? Do you have a variable speed or two speed pump that you could turn up?

 

[Jpollock]

I already cleaned the sand filter twice. The water is now clear. I made sure all the fittings were tight. It is a single speed pump from what I can tell (Hayward SP5610). I thought the pressure gauge was at zero but it's actually all the way around the dial against the pin at zero (ie. showing super high pressure). I can't see that being normal?
any other thoughts on what my problem might be?

 

[danpik]

It is possible that you have a faulty pressure switch. A simple jumper across the terminals can confirm this if you are positive that you have adequate pressure from the pump.

 

[Jpollock]

I think there's super pressure by the volume being pumped into the pool compared to last year.
where might I find the pressure switch on a Hayward matrix pump?