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Support => Plumbing, Gas fitting and Drainlaying Apprentice Support => Topic started by: sharks on March 31, 2010, 10:47:30 PM

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Title: help with a exam Question
Post by: sharks on March 31, 2010, 10:47:30 PM
Hey guys, sitting my rego in june , just came across a question I cant work out.

Give four reasons why gas pressure in an installation may be insufficient at times of high consumption?


I have come up with two answers I think are correct, need two more

1. pipe size to small
2. low supply pressure


thanks
Title: Re: help with a exam Question
Post by: hefzibah on April 01, 2010, 10:01:51 PM
When doing any exam, make sure you put down an answer, even if you are unsure. but first write the answer that you do know followed by the answers you are unsure of, markers will mark first 4 , 6 ,7  etc answers.Answering your question write down anything that will affect an installation, incorrect size of GMS is another answer.. hit the books and good luck..
Title: Re: help with a exam Question
Post by: crusty on April 05, 2010, 10:18:33 AM
The filter in the meter regulator could be packed with dust.
Title: Re: help with a exam Question
Post by: crusty on April 12, 2010, 10:43:36 AM
Another thoght just came to mind!  The orifice in the regulator is possibly too small to carry the volume required on high demand.
Title: Re: help with a exam Question
Post by: crusty on April 12, 2010, 01:21:03 PM
Another thought just came to mind!  The orifice in the regulator is possibly too small to carry the volume required on high demand.


I must be loosing my marbles! A couple of other things that cause regulators to act up pressure wise are: May have a broken or fatigued pressue spring.  And also a blocked breather hole which will prevent the diaphragm from moving either up or down, so the pressure will be high or low depending on the inlet pressure.
Title: Re: help with a exam Question
Post by: yzhardy on May 16, 2010, 12:36:42 PM
I would put it this way:

1. Inadequate pipe sizing.
2. Incorrect sizing of GMS or first stage regulator
3. LP Gas unable to evaporate sufficiently from the bottles.
4. (Possibily) Blocked line filter.....