Commercial help

[Tom Mead]

Hi I am a gas safe domestic installer and am looking to move to New Zealand. As part of this they expect me to complete a theory paper on commercial package burners of which I haven’t got a clue!.
Can anyone explain to me the concept of the below diagram I know what all the valves are called but am unsure on how this gas train operates?.
I specifically need to know which route the start gas takes ie through valves 9 or 11/12?.

 

[bacon_sandwich]

i would expect the slow opening valve to be the main, so i guess the fast opening is the start valve

 

[Tom Mead]

That’s what I initially thought. But valve 7 is also slow opening fast closing which is before and covers both routes so isn’t a fool proof way of looking at it.
This is the answer I need from it below but until I know how it operates I haven’t got a chance. I know all the rectification stuff but I’m unsure if there is 2 fans on a package burner???.

 

[Tom Mead]

All these q’s relate to that schematic

 

[Brambles]

The schematic is numbered in the operational sequence. If you sketch out a P and I D, the answers to the first questions will drop out.

The second set of questions relate to general philosophy and good practice of burner management systems not just the schematic.

The object of the question is to see if you have the skill and ability to “backfit” the operational logic to a schematic. The normal process is to draft the P and I D, then develop the schematic.

 

[Tom Mead]

Thanks. That’s the problem they have given me this but I’ve no basic knowledge on how commercial burners work. I need a basic understanding of what components are within a commercial gas train.
Eg: in the first page of questions it asks : The controller starts the fan to purge the ———- and ————

Then on the next page g asks: Why does the system start the burner in the first place
And question h asks: Why does the controller start the fan as the second step.

What does starting the burner mean is there a second fan in a commercial burner???, I need help with a basic understanding of the components, thanks for reply’s so far.

 

[Brambles]

Tom,

Are these questions from test papers for the New Zealand PGDB (Plumbers, Gas Fitters and Drainage Board) exams? If not, what are they for?

If so, you need to know the syllabus and the NZ rules and regulations. For gas, it is not dissimilar to the process that you go through in the UK to become gas safe registered. That is to say you need to know the regulations inside out and be able to apply your UK technical skills to answer the questions. In my view it is in some ways harder than qualifying in the UK. You have to qualify for both LGP and Natural Gas together, the papers are not multiple choice and are generally 3 hours in exam conditions. They supply the regulations and appropriate formulae for you (ie. open book).

My recommendation would be that you look at the syllabus and read the NZ regulations before trying to do test papers. The test papers then give you an indication of what you need to revise further. Just doing the test papers won’t give you the breadth of knowledge that you will need for the exam.

There are probably courses run in the UK to get you fully up to speed for these exams.

I assume that you are already Gas Safe Registered in the UK? If not, that might be the best starting point for you.

Hope the above helps and good luck

 

[Tom Mead]

No they are from the skills assessment company that the PGDB use to transfer our uk qualifications over to say that our apprenticeship in the uk is equivalent to theirs.

In NZ they do commercial as part of apprenticeship whereas here we don’t so they have given me this one module to answer to get a certificate which then allows me to start doing the PGDB exams.

I am gas safe here (residential) for 18 years just never done anything on commercial and need some background knowledge.

 

[bacon_sandwich]

https://www.rielloburners.co.uk/images/content/downloads/RIELLO_40_GS20D_20063817-1.pdf

The above link is for a well known international burner manufacturer for the commercial sector. The process of starting a burner is quite well described , hope it helps.

 

[oz-plumber]

Hi Tom,
I have no idea why this diagram and questions are part of the regulations.
These relate to a completely different class of gas work, in Australia anyway.
We are governed by the same regulations and follow the same practices.

Did they send you the forms hard copy or did they email them to you.

I would love to see the questions on the forms - just to see what questions are asked.

PM - me

 

[Tom Mead]

Emailed them to me there are q’s on air blast, nozzle mix, diffusion neat gas as well as stuff I’m familier with. I’ve posted above some pics of the q’s they need answering. Will pm you.

 

[Tom Mead]

Thanks bacon will have a look now.

 

[Brambles]

The schematic that they have given in the question is for a Taymac, LPG low pressure hot water boiler.

 

[Tom Mead]

Cheers will look into that brambles. Am I looking too deep into this?, question g is why does the system start the burner in the first place

I took this to mean something in the burner head is started up first ie a second fan or something special that happens in the burner head before the air fan runs. Are they literally meaning why is the appliance started in the first place????.

 

[Gasmk1]

I took this to mean something in the burner head is started up first ie a second fan or something special that happens in the burner head before the air fan runs. Are they literally meaning why is the appliance started in the first place????.[/QUOTE]
Yes

 

[bacon_sandwich]

I read it as a call for heat, i.e. thermostat / timer etc

 

[Tom Mead]

lol what a pointless question

 

[bacon_sandwich]

well yes and no. Its the first thing you need to check when you go to a fault "heater not working" - i know its bizarre but in my world its a good percentage of"faults" are not burner or burner controls but simply someone has turned the stat right down, then gone home. Next shift come in and report "its very cold " to supervisor , lol

 

[Tom Mead]

Yeah I suppose I just thought from a testing perspective they would be going a bit deeper than a switched live.

 

[Brambles]

Bacon Sandwich is correct - it is not a trick question. From my interpretation the object of the question is to get you to draft out a control system around the piping layout that they have given you. Equally, they could have given you a control system philosophy Nd asked you to draft out a suitable piping layout.

The way to answer this type of question is to draft out the process logic on a blank piece of paper first - check it works, then answer the individual questions. If you do it piecemeal, ie. answering the individual questions in an adhoc manner, you will probably miss a key step.

Logic starts ( I cannot draw it out on here, but in words

Boiler commissioned and set to operation, valve 4 manually opened, thermostat calls for heat, fan on, air pressure differential achieved, gas valve 7 opens, gas pressure (8) is achieved, purge to pilot valve (12) commences....

You may also find it easier to draft out the burner test procedure - that often helps crystallise your understanding of the operating sequence.

On a final point try to use NZ not UK terms to describe items.

Hope this helps to get you going

 

[Tom Mead]

Yeah I’m fine with it all I expected it to be something else. As I’ve not done any commercial before I didn’t know if a burner was different to a domestic in its operation in some way which I now know it’s all pretty much the same theory just on a different scale.
Thanks for everyone’s help I submitted it last night so will see how I get on.

 

[snowhead]

Having just returned from N.Z following a 3 week visit to my Son who's temporarilly living /working there, I have few relevant comments.

It's a lovely place to visit and holiday.

But if I had been considering moving to N.Z, I wouldn't be now.
The main reason being the rediculous price and quality of property nowadays and the fact you can't initially choose where to live.
Property prices have risen dramatically in recent years due to excessive immigration, the reason now why they are so strict on who and how many get in.

My Son is renting a 5 year old 4 bed house currently valued at £750k. (may seem cheap to U.K southeners).
As is common with most N.Z properties it does not have central heating, just a log burner in the lounge /diner which also faces North (where the sun shines from down there).

The original N.Z houses were built on relatively large plots, so nowadays it's not unusual to see 3 or 4 other houses built very close together in the back gardens.

 

[Tom Mead]

Depends where you live Auckland, Wellington and Queenstown are mental expensive but I am not a great lover of cities anyway.
Outside of these areas it’s still cheaper than the uk, yes you no longer have acres and acres but you can get a 500m2 plot with 3-4 bed house on it for £300k ($550k) easily enough.
We want to go for the scenery and lack of people. This country is so overcrowded now a day out at the beach is a truly awful experience on a hot day the only place I’d move in the uk is Scotland but then you got the small issue of the weather