# Rex C100 PID going crazy, just wants to blow up the house!



## ShaunChris (May 4, 2015)

So I own a Fracino Piccino that had been pre-modified by it's previous owner with a RKC Rex C100 PID.

The PID worked well for the past 2-3 months.

Temp was set to 94 and shots pulled were great.

However the machine somehow started leaking water underneath, sent it for repairs to one of Fracino's official repair companies in the Manchester area.

Came back to me and the machine isn't leaking anymore, but somehow the PID is messed up.

*PREVIOUSLY*

*
*Switch on the machine, PV (Present Value?) shows something like 20 degrees, then it slowly climbs to 94 degrees within about 5 minutes, and holds steady.

SV (Set Value?) is at 94 degrees.

*NOW*



*
*Switch on the machine, PV shows something like 20 degrees....

SV is still at 94 degrees.

Then PV climbs...

PV hits 94 and keeps going...

PV hits 120 and keeps going...

PV hits 150 and keeps going...

Still with me?

PV hits 200 and keeps going...

PV hits 250 and keeps going... (Is it even possible for the boiler to hit 250?!!?)

Somewhere around the 300 mark PV just defaults to 4 circles.

Apparently that's the code for "Overscale, temperature too high".

Well, colour me surprised.

Anyway, that's how things are now.

Two main issues I suspect:

Either somehow the software in the PID got changed and some settings are massively off.

Or something is disconnected or whatnot within the boiler itself.

Any suggestions?

I've dug up the guide for the RKC Rex C100 and promptly got lost in the technical magic that a blockhead like me does not understand.

I've tried using the autotune function two ways:

1.) Press and hold SET until ATU comes up, set it to 1, and let it do it's business

2.) Same as step 1 but I set SV to be within 20 degrees of PV.

Both have the same result, the AutoTune light keeps blinking to show the machine is learning...

PV goes up....

Up...

Up and away...

Until I get 4 circles indicating OverScale / Temperature too high again.

Any ideas guys?


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