CCN1.....ACS...

[ChrisR]

Take screw cap of first,then adjust BP screw accordingly.

Yep, you'd be surprised how often guys don't know there's cover screw so try "adjusting" that!

You got there with the liquid/vapour thing, almost. If you want a quick action the vapour one is better, like for detecting a pilot is lit, but if you want a proportional thing, for use in a thermostat, the liquid one is better, so a bit the other way round from what you said on that.
Point I was getting at was that they can be used for opening a gas valve directly with no need for electric power, OR for operating a microwitch.
Expect to find both on the rig.

So you've just got thet oven 2 bypass? one bypass? thing to go...

 

[Gastel]

So you've just got thet oven 2 bypass? one bypass? thing to go

Right....so.......when tap on thermostat opened and pilot lit, gas opens full rate thru thermostat valve & into FSD/burner, when thermostat reaches required temp valve closes......but still maintains temp thru by-pass rate to burner, when stat cools down valve opens again (depending on setting) increasing gas to burner therefore increasing temp & so on.....if pilot was to go out FSD would close valve to burner?

 

[Terrywookfit]

Why are relay valves still covered in the assessment ??
(They were last year anyhow)

I have not even seen one for at least 20 years!! (well ok once every 5 years at acs )!

 

[ChrisR]

Terry they're still in the book I think. Of course I couldn't tell you whether they're in the assessment or not. But I , er , can't remember exactly what they look like

Gastel, nay lad, ovens (of this type) don't have pilots.

Needs a picture really, but I'll try:

Arrive at oven. No gas flowing.
Push knob - small amount of gas goes through. Light it.
Once the liquid expansion flame failure device is hot, it holds the gas valve open, to the bypass tube.
If the flames blow out, the leffd closes the gas off.
The main thermostat, typically a liquid expansion operated thermostat or rod type, opens and closes the main gas valve according to the temperature in the oven. Flames go down when temp reached, so the oven's at the "bypass rate".
See?
Now you're gonna tell me that's what you said, or meant to say...

 

[Gastel]

If I change the word "pilot" to flame doesn't that make sense??

Right....so.......when tap on thermostat opened and flame lit, gas opens full rate thru thermostat valve & into FSD/burner, when thermostat reaches required temp valve closes......but still maintains temp thru by-pass to burner, when stat cools down valve opens again (depending on setting) increasing gas to burner therefore increasing temp & so on.....if flame was to go out FSD would close valve to burner?

 

[chrishutt]

Take screw cap of first,then adjust BP screw accordingly.

Yep, you'd be surprised how often guys don't know there's cover screw so try "adjusting" that!

Unbelievable that there are still Corgi registered operatives out there who don't know how to adjust burner pressure on a MFC.

Gastel, you might like to know that you're not the only one learning a thing or two from ChrisR. There's some old hands (well, one at least) who thought they knew it all but are digging out the books to check after reading this thread. Anyway the best gas operatives are the ones who never stop learning - you're off to a good start.

 

[Gastel]

Cheers chris........means nothing tho unless I pass this bloody assessment!

 

[fitz1]

got to resit mine in april. are the questions more in layman terms now.last time i got 12 questions wrong due to marking the wrong one on my sheet.i.e i marked E when there wasnt an E in the question, it should of been D. but i didnt think the questions where worded well anyway.

 

[Gastel]

What did you fail on fitz? Got my appliances assessments on Mon,Tues......how did you find them?

 

[namsag]

Fitz . renewal is two papers we done flues and pipework seeing as 35mm is now part of core. Hardest part is a long winded calc on purge volumes.. About 32 questions on one and 26 on the other then there is a thing called a paws (spelling?) book which has pictures of dodgy installs etc and you have identify them and a few more question prob another 20 in total.

Papers should not take more than an hour each.

 

[fitz1]

didnt fail. when he asked me to check them i realised what i had done. regarding appliances- keep a look out for pieces of wire wool stuffed where it aint supposed to be and have a good look at the flues.always bypass on cookers and blocked jets and probably thermostats.take your time and check MIs.(burner pressures)

 

[namsag]

Also be careful if you have to ask for manufacturers instructions that they give you the exact ones and not something that is for slightly dif model

 

[ChrisR]

Right....so.......when tap on thermostat opened and flame lit, gas opens full rate thru thermostat valve & into FSD/burner, when thermostat reaches required temp valve closes......but still maintains temp thru by-pass to burner, when stat cools down valve opens again (depending on setting) increasing gas to burner therefore increasing temp & so on.....if flame was to go out FSD would close valve to burner?

Um. Keep it simple and precise. Look at the drawing and I expect the steps make more sense. Don't confuse the function of each part:
eg
when tap on thermostat opened and flame lit, is confusing the lighting, with the thermostat. It'll light at any thermostat setting
but still maintains temp thru by-pass to burneris confusing the temperature control with the bypass. The bypass is there only to keep the burner alight. The thermostat valve is there to regulate temperature.

You'll obviously get through fine with the knowledge you have, but it'll be easier if it's all clear in your mind.

There are lots of "surprising " candidates, like the guy who was on his 3rd 5year retake and didn't know let-by pressure.
I keep being told there's a liquid in a thermocouple
Many have no idea what a draught diverter is
Most don't know how to check that a FFD, on say a grey button gas valve, isn't letting by
Everyone condemns a wooden chimney which has a liner in it
Many think existing pipework has an acceptable leak rate
Most don't know why positive pressure boilers are dangerous
Apparently you can check for let-by by smothering the handle with ldf

A major problem is that candidates can turn up claiming experience when they don't have any. They have to get a signature of a corgi to say they have, but there's no shortage of liars, and no follow-up.

Still plenty of stuff I don't know, or find I've been getting wrong, by the way!

If a cable's in a plastic conduit but within 25mm of gas, is it OK? Regs say Insulating Panel makes it ok - plastic is insulating. I don't know!

Fitz as far as I've seen some of the questions are as daft as ever. There's a rumour that some of them are deliberately misleadng so CITB etc can be suspicious if everyone gets them right!

 

[Gas2Air]

My biggest advice is be calm, yes you will be nervous etc but ask if your unsure on anything and everything. They want you to be showing safety, competence and knowledge not some expert type who think they know it all, they will fail

I forgot to (i know) to lift the ckr lid on relight and purge, however i knew i had done wrong, mentioned it to the assessor and redid it again. They watch everything, but if you try and hide a mistake you will get an instant fail. You will get a few marks on the record sheet and almost all will have a quiet word with you to pass on 2nd attempt.

Ventilation and flueing are the biggies and in the written multi choice too.

I did mine in July this year and never had a control rig, just matched what control did to which item. Very straightforward that tbh.

 

[Gastel]

I did mine in July this year and never had a control rig, just matched what control did to which item. Very straightforward that tbh.

Wish my test was the same, we have the control rig set up with faults which we have to locate & repair then take burner pressures & check FSD's aswell, its trying to remember everything!

1 more question on purging.....when Ive commisioned appliance do I have to work out the purge volumes or can I get away with lighting at cooker as most purge volumes shall be under 0.03ft3 methinks

Chris, thanks for the advice.