Sparky advise wanted

[ggf]

Hi I have been a time serverd electrician since I left school,and have been very lucky to have been disciplined in domestic commercial and industrial,my spacialty is control boards and boiler wiring.
I have just been asked by a refrigeration company to start wiring all there cold rooms and freezers installations, so I have wired in a few now, but I must admit its like the first time i wired in a s plan on a domestic boiler system, or commercial boiler, I don't have the first clue what and why..
So I have found myself spending hours trying to research to learn, but your industry seems to be like getting into castle grayskull,
Please could you offer any advise on control courses? that i may attend or any good books that can help me?

[al]

Check out Ellis training, I've used them for apprentice training and found them excellent.

http://www.ellistraining.co.uk/courses/electrics

[Rob White]

.

Are you any good with schematic wiring diagrams?

Are they expecting you to build the panels and all the equipment or
are they wanting you to wire all the component parts together?

As you know there is a big difference between designing and building
and just wiring all the bits together.

All the courses that teach will be at a fairly basic level, they will
explain what is what and how they work with each other but in
truth they won't go into great detail.

You have the best grounding in what you do already all you need now is to take
that to the next level. The training on offer might not do that for you, you know
more now as an electrician but you just need to apply that t o a fridge.

I know I'm teaching you to suck eggs and I don't wan't to sound patronising
but you are in a very grey area, stuck between electrical and fridge.

The only way to do it is by doing it and normally that would be under the
supervision of a fridge electrician. You are doing the right thing and have not
fallen into the common trap of assuming fridge controls work the same as
heating controls.

First things first are you expected to design the panels and controls or are you
just expected to wire up all the pre-built component parts?
Secondly can you read a schematic?

Regards

Rob

.

[ggf]

Hi Rob thank you for your reply, All is expected is just to wire up, If they wish for me to build a control panel then I can do so, but normally I have a better understanding how they work, I can read schematics but i can't seem to find any.
For example I have a walk in fridge, they have told me its working on a pump down cycle, I have a controller, Hp/LP switch Evap fan, condenser unit and solenoid valve to wire, If I have a diagram jobs a good one as thats my bread and butter.
Due to the fact I can't find any diagrams I let this one go, as i don't want egg on my face, but I am now very keen to find how its done as knowledge is power. if you can offer any help it would be very appreciated Rob

[Rob White]

.

Unless it is designed and built by a company you won't find a schematic
for the whole system, more than likely you will find individual schematics
for the individual components and you will then link them together.

See the controller and that should have a drawing.

Normally the controller switches the evap fan and defrost and
either the liquid solenoid valve or compressor. If the the controller
switches the the liquid solenoid valve then the LP switch, switches
the compressor on and off on pressure. The HP switch if separate
from the LP, controls the compressor only.

see

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCInFjcOWk8kCFYE6FAodcuQBnw&url=http%3A%2F%2Fwww.lae-electronic.com%2Fscheda.php%2Fcod%3DAD2-5%2Fkey%3D58&psig=AFQjCNEDrw684eCDT0gDSCcRu698bOpRbw&ust=1447702569650249

http://www.lae-electronic.com/backend/prodotti/img_upload/img3_3/070523085880_AT2-5BS4E-AG.jpg

http://www.berndt-contec.de/wp-content/uploads/2012/08/AC1-5TS2RW-B.gif

http://www.berndt-contec.de/wp-content/uploads/2012/08/AC1-5PS1RW.gif

Regards

Rob

.

[ggf]

Rob thank you for your reply, and for the information, so would i be correct in saying-
Evap fan and defrost wired into the controller, the compressor terminal will be connect to the Liquid line solenoid valve, take a perm live out to a isolator then through the LP switch to control the compressor.
So when the fridge gets to temp the controller switches the compressor relay which drops power to solenoid valve, causing the compressor to pump all the remainder into the receiver until the LP switches off.

[monkey spanners]

Rob thank you for your reply, and for the information, so would i be correct in saying-
Evap fan and defrost wired into the controller, the compressor terminal will be connect to the Liquid line solenoid valve, take a perm live out to a isolator then through the LP switch to control the compressor.
So when the fridge gets to temp the controller switches the compressor relay which drops power to solenoid valve, causing the compressor to pump all the remainder into the receiver until the LP switches off.


Thats how i do them, though i would power the compressor from a contactor and overloads, you can then fit a NC auxiliary contact to the contactor to feed the crankcase heater.

[Rob White]

.

Monkey beat me to it :D

Rob

[ggf]

Monkey and rob thank you for your advise and help, very much appreciated advice-

[Tayters]

Not many books that explain that kind of stuff. Best way I found which it looks like you've already sussed was to figure out existing wiring diagrams (yep, even photocopied them and took them home, beats a night out. Hmm) and ask about bits that didn't make sense of have a play about on an existing system. Found I had to ask a few people before getting a proper answer, Skelator setting a few traps along the way.

I have found this forum the most help with specific questions.

Older systems seemed a bit crankier. For example defrost feed might come from an NC auxillary off compressor contactor so heaters can't heat when compressor operating. Venner defrost timers? Jeez, got it easy now with electronic controllers. Most systems standard but always a leftfield one to make you think.

Cheers,
Andy.