Water Level Pressure Switch (Advice needed)

[GreggElectrical]

Hi.
I was called to a local hotel to find a fault. Fault was traced to commercial dishwasher in kitchen and more specifically the element.

Against my better judgement I decided to order one up and repair it for them (what could go wrong?) Whist changing the element the manager began to tell me how sometimes the machine spills water everywhere. After the element was fitted I began looking into the over flow situation. The fill level is controlled by a pressure switch below:

I adjusted the dials assuming this adjusted the fill level but no luck. I then found the pipes were all blocked with lime scale (the whole thing was bunged up everywhere). A good clean out and we are back in business. However I have now adjusted the pressure switch and I'm not sure how to set it back up again.

Can anyone tell me what each of the dials do? The switch is the one shown in the picture. There is a third dial at the top left barely visible in the picture.

Any help would be much appreciated.

Thanks

Austin Gregg.

 

[Amp David]

Think you'll need to find the manufacturer and get a data sheet or instruction sheet.

Not sure if all switches are the same you see, someone on here may have used the same one before though

 

[Deleted member 26818]

I believe the three dials are to control the 'Min' water level for the heater, the 'Min' level for the drain pump 'off' and the Max level for the drain pump 'on'.
You would need to establish what these levels are from the manufacturers and at the same time you could establish which dial controls each function.

 

[oldtimer]

One dial is the pressure you want the unit to switch to the other is the differentilal or the band that it switches ie if you set it for 2mbr then it would switch off an on if the pressure went just below but if you set the differential to say 0.6mbr then the switchwould call for water at 1.7mbr and switch it of at 2.3mbr.

check the manufacturers settings but also either have a pencil a a fine perminant marker and always but always mark any switch like this before you adjust it easy for me to say but its simple and it works and you can always go back to where you started from. I have seen this befor on a AHU where the maintenance guy tried to fiddle with the setting so when they called me out all I had to to was put everything back to the settings

 

[Knobhead]

Can't fault that OldTimer :yes:

 

[oldtimer]

Just to add to the example above the manager of the hospital pulled me into his office to give me a ballocking in front of his maintenance guy and his 2 labourers so he said your controls are crap they dont work and how come we have to pull you out every 6 weeks and you sort it within 10 minute and what are you going to do about it . I said to you want it sorted that it can never happen again he said yes so I walked over to the maintenance guy and pulled the small screwdriver out of his top pocket I then threw it in the bin and walked out the door. The look on that guys face was a picture indeed and the funny thing is I never got called out again

 

[Knobhead]

I had similar with a PLC program I’d written. A couple of times in a shift the system would go haywire. It got to the stage that I’d had enough of getting a rollicking for what was operator error. The plant operator had got it in his head he could work the machine faster in manual.

I arrived at work on afternoons to be greeted by a bunch of managers, someone had nearly been killed by this machine. They were after my blood! I let them have their say and then asked them to come to the PLC station, I’d got something to show them. I call up a register table, and then asked what time the accident happened. “At 22:34 the machine was turned to manual, it was at position XX, the machine conditions were YY”.
No one knew I’d programmed a spy in the cab in to the machine. I didn’t get any more complaints after that for some strange reason.

I don’t like pulling dirty tricks like that but why should I get the aggravation.