Questions from a 4th year Apprentice

[Newbiegoeasy]

Re: Questions from a 4th year Apprentice

Aw man now I’m really confused lol! I guess i should be content with what Dave says; it’s a bit of a non argument and I’m better concentrating on learning how to fault find and fix things rather than random questions. That is basically what my boss has said before too. I just hate not knowing things, you know?

Is there any really good electrical theory books you guys would recommend?

An insulation tester? Unless there is a setting on my multimeter to test for low insulation – then no.

[electrofix]

Re: Questions from a 4th year Apprentice

an insulation tester test at a voltage of 250 or 500 volts still known in the trade as a megger. A bit like biro and thermos flask who brought them out first

but you should also be familiar with a pat tester

as far as theory is concerned learn DC theory first than move onto AC later as its more complex than you think. get a grip of Ohms law its fundamental to understanding how electricity works

what you could do with is an electricans course just for the theory.

Dave

[timdowning]

Re: Questions from a 4th year Apprentice

City & Guilds 7202 Level 1 is a good place to start.
This will give you the basics & will lead onto other courses which you can tailor to suit your needs. Predominately moving to a qualified Electricians status…

[Newbiegoeasy]

Re: Questions from a 4th year Apprentice

Okay! Fridge freezers!

Is there an easy way to diagnose fridge freezer problems? For example:

(Assuming the obvious that the appliance doors are sealing correctly, is loaded correctly inside, is not too hot/cold in the room itself etc. We are talking about actual faults with fridge freezer units specifically)

1. Freezer compartment ok but fridge compartment too warm – in need of thorough defrost, if problem persists then shortage/chokage of gas.

2. Compressor running. Both fridge and freezer compartments too warm – shortage/chokage of gas.

3. Compressor not running. Both fridge and freezer compartments too warm – thermostat or compressor problem.

That should be enough just now to get some discussion going…

[Martin]

Re: Questions from a 4th year Apprentice

1. You answered that
2. You answered that
3. Electronics also suspect, but yeah you got the other possibilities covered

Has your boss lightened up any since you last had training issues?

[Newbiegoeasy]

Re: Questions from a 4th year Apprentice

My boss is an animated, frustrated person who goes off on long winded tangents. And has always been this way. With, like, everything in life. So most of the time you ask a question you get an animated, frustrated, long winded answer. But the fault also lies with me. I make the same mistakes over and over, and I find it hard to focus. For someone who has never, ever, had a previous interest in engineering – I find it hard for my brain to adjust to the purely logical way of thinking. I’m sure that must be frustrating.

We are on good terms. Don’t get me wrong with any of this topic. It’s just there are some things I never got a simple straight answer for. And for someone 4 years down the line, I find this unacceptable imo. It would be easier for me at this stage to seek a little clarification elsewhere rather than get my head bitten off/be made to feel stupid.

So, with that said :rotfl: :

1. I get confused with frost free and normal fridge freezers here. I understand that with frost free there is a fan in the freezer that simply blows the cold air up from the freezer to the fridge via duct behind the plastic moulding at the back. If this gets blocked with ice then a thorough defrost is needed. However, on a normal unit, what would stop the fridge from cooling efficiently? The same principle? Just the insulation being blocked with ice?

3. When you say electronics also suspect, do you mean if there is a digital board/thermostat?

I also get confused how to tell wether a compressor is not running due to a faulty thermostat, or an actual compressor problem? Is there any hints, tips or tricks to tell the difference?

Thanks again!

[boselecta]

Re: Questions from a 4th year Apprentice

As Martin says you have to put pressure on your boss to get you a insulation tester as your fault finding will always be limited with a multi meter.

This really is a good question you have asked and not a easy question to answer. You have been given some good theory regarding AC here.

The basic theory is right here but within the complex circuitry of individual modern machines the ‘hot’ wire can be either the live or the neutral and does switch bonding from one to another. It takes a while to get your head around.

Good reading here:
http://www.eetimes.com/document.asp?doc_id=1272972

[Martin]

Re: Questions from a 4th year Apprentice

Newbiegoeasy wrote:1. I get confused with frost free and normal fridge freezers here…….

3. When you say electronics also suspect, do you mean if there is a digital board/thermostat?……….

I also get confused how to tell wether a compressor is not running due to a faulty thermostat, or an actual compressor problem?

OK so lets pile some information in here for you, starting with: –

http://www.ukwhitegoods.co.uk/help/fix- … rigeration

http://www.whitegoodshelp.co.uk/frost-f … g-fridges/

[Newbiegoeasy]

Re: Questions from a 4th year Apprentice

Great info! Having read through everything twice , I do still have some questions though if that’s okay?

NOTE: I have not been taught much about fridge freezers simply as it is something we don’t really do. It is hard for us to get the parts for American style ones so we just don’t look at them and almost any fridge freezer with a digital board seems like more hassle than they are worth in terms of spending both time and money on them. We don’t re-gas either. We replace the odd traditional thermostat but not much else.

Therefore, i have not come across a lot of fridge freezers. However, i dislike feeling like I’m looking at an alien object when i do come across one and would like to know more of their inner workings!

1. The “thermostatically controlled air flap to control the airflow into the fridge” …how common are these for failing? I have never even heard of these!
And are these pretty specific to American style fridge freezers?

2. Do most frost free fridge freezer have a defrost heater? Or, again, is this pretty specific to the American style?

3. Are defrost timers even inside modern fridge freezers? Or built-in to the PCB? I’ve never heard of these either :/

4. In regards to non-frost free fridge freezers, if they do not have a fan blowing up cold air from the freezer to the fridge, then what regulates the temperature of the fridge? Are there 2 different compressors and thermostats?

[Lawrence]

Re: Questions from a 4th year Apprentice

That’s odd as if you are an apprentice for who I think you are ,you carry out warranty work for a manufacturer that produces a wide range of refrigeration,predominantly side by sides ,or is that why your questions mainly relate to side by sides ?

[Newbiegoeasy]

Re: Questions from a 4th year Apprentice

Sorry, i don’t follow. Side by sides? We don’t do any refrigeration warranty work.

[Martin]

Re: Questions from a 4th year Apprentice

Newbiegoeasy wrote:Great info! Having read through everything twice , I do still have some questions though if that’s okay?

Wow! These questions keep on coming don’t they?

Let’s compress the answers because you and your company don’t mess with fridges then there is little need to dwell. But it is only polite to help a fellow ‘in the trade’. 😉

1: Yes very common source of trouble.
2: They all have.
3: In all types. Electronic controlled are built within the circuit.
4: Two separate evaporators, two stats or Thermistors.

I have a couple of questions for YOU : What make of insulation tester did your boss supply you with in the end? And how are you getting on with using it?

[Newbiegoeasy]

Re: Questions from a 4th year Apprentice

Look, I have already asked a lot of questions here and am really gratefull for all the advice. If I’ve outstayed my welcome please let me know.

I spoke to my boss and I was told that everything I need is on my multimeter and also that we don’t do PAT testing anymore. Apparantly, as long as I can open an appliance and follow and understand the wiring, how the wiring and mechanics work and relate, and test for live and neutral – then I’m okay. There are some circumstances where we would test for reaistance but they are few and far between. I’m not sure if that is good enough? But to be fair, for most of the work we do in this high pressure fast paced environment – our diagnoses are rarely wrong.

I like getting the opinions of you guys here and always think up more questions regulalry. That is, if I’m not being too pestlike at this end of ‘the trade’ 😛

[Andy jones]

Re: Questions from a 4th year Apprentice

So does your boss not insist on doing insulation tests after a repair??

[Newbiegoeasy]

Re: Questions from a 4th year Apprentice

Nope afraid not

[Author]

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