Central Heating Exam Questions NVQ

[Gavin2008]

Just take one of my NVQ exams not sure how I did. Could do with some help with the answers to these questions if anyone can shed some light on them. I know there are lots of answers but the questions I have are multiple choice. So please pick from the ones below. Thanks for the help.

Q. where would you find the wiring diagram for a fully pumped system?

A. Manufacturers instructions or the building regs?

Q. When the hot water is running some radiators are heating up. Is there
a problem with.....

A. The pump or the valve?

Q. The pressure test is 1.5 times the working pressure but for how long?

A. 30 mins / 60 mins or 90 mins?

Q. How do you remove flux from the system?

A. Get the system up to working temp then drain down?
Turn the stat up to full or put the corrosion inhibitor in the f & e tank?

 

[sonray ltd]

Mi - valve - 60 - get the system running and drain.

 

[Mohammed786]

im revising central heating and i want to see if i got these questions right please could u have ago thanks

1 Theconnection of an open vent pipe and a cold feed pipe, can be made to a fullypumped system using

a)an automatic air vent
b)an injector tee
c)an air separator
d) adiverter valve.

6 Azone valve in a pumped heating circuit is designed to

a)isolate the circuit when the desired temperature is reached
b)permit the system to be heated to temperatures above 100°C
c)stop the pump vibrating on its fixing mountings
d)prevent water from the flow and return pipes mixing.

10With reference to hot water heating, an injector tee would be used where

a) areturn pipe from a gravity fed cylinder and a return pipe from a pumped heatingcircuit are combined
b) acommon cold feed separates to feed the hot water storage cylinder and theheating pipework
c) aflow pipe from a cylinder and a flow pipe from a heating circuit are combined
d)the secondary open vent pipe and the primary open vent pipe are combined.

11 Amid position diverter valve

a)provides priority circulation to the hot water circuit
b)provides priority circulation to the heating circuit
c)feeds both the hot water and heating circuits simultaneously
d)is used to discharge water from the system if it overheats.

12When fitting thermostatic radiator valves, a general principle to follow isthat

a)all radiators should be fitted with thermostatic radiator valves
b)at least one radiator should be fitted without a thermostatic radiator valve
c)only radiators on a dwelling’s first floor should be fitted with thermostaticradiator valves
d)only radiators on a dwelling’s ground floor should be fitted with thermostaticradiator valves.




17In a combined hot water and central heating system, including a feed andexpansion cisternwith gravity primaries and pumped heating circuits, the

a)warning pipe to the F & E cistern may be connected to that of the cold waterstorage cistern
b)water level in the F & E cistern must be adjusted to 100 mm below the floatvalve whatever the
finallevel
c)water level in the feed and expansion cistern should be set to allow sufficientroom for thermal
expansion
d)open vent pipe for the primary circuit may be connected into the secondarycircuit.

20Which one of the following assists in the removal of flux from heating systemspipework?

a)Hot flushing a system as part of the commissioning process.
b)Adding soap solution to the system after testing.
c)Setting the working system temperature above 60ºC.
d)Installing all pipes with a fall away from the drain valves.

 

[mountainman]

U give us your answers first!

 

[Mohammed786]

I hope this helps if there are any wrong will/could you correct them thanks
1) A
6) A
10) B
11) C
12) A
17) C
20) A

 

[Dannypipe]

You've not got them all right.

 

[Mohammed786]

ok ....

 

[Dannypipe]

Well mate, I don't just want to give you all the answers as that won't teach you anything. Which ones are you not sure about?

 

[MattWeth]

Another thread that you're asking for answers to your questions...

Get your head in your books / course notes - us answering your questions won't teach you anything.

 

[Mohammed786]

1

11
&
17

 

[PlumbBobBob]

i make it three or it could four by now

 

[Dannypipe]

Quite happy to help him, but as said, just telling the answers is ok for a member of the public who wants to know out of interest....however for a would be plumber, you should learn properly to help commit it to memory.

Don't worry, every day is a school day and even the most experienced plumbers don't know it all.

 

[Dannypipe]

OK - Start with number 1 - you are indeed wrong.

What help would be fitting an AAV to the cold feed/open vent? Have a think.

 

[Mohammed786]

1, 11, 17 plz or even all thank

 

[Mohammed786]

Number 1 is c

 

[Dannypipe]

That's what I would go with. Do you know why?

 

[Mohammed786]

No but im going to read it up....

 

[Dannypipe]

Well, you wouldn't need to release air with an AAV. You have an open end. (The open vent). You wouldn't need an injector tee, and what use would a divertor valve be.

So it can be useful to seperate water and air, and help the system vent. It isn't always required, and more often than not, you will NOT find one installed.

 

[Dannypipe]

Remember there are strict rules regarding the distances of the cold feed and the open vent. Get you head in your books and read up on this.

 

[Dannypipe]

Next - I make it that you have number 10 wrong.

 

[Mohammed786]

10) a thanks

 

[Dannypipe]

Hmmmm. He seems to have gone!! Scared him off?


If he returns, (I'm off out).

Tell him to look at the pic I will post......

Let him know that I make it that he actually got 11 correct...but not 12 (in my opinion any way!).

17, I'd agree with him on c, though its an annoying question.

Oh and as for 20, I would agree. A is the answer.

Good luck in your future career. Keep studying. Its a very satisfying way to make a living but as said, every day is a school day.

 

[Mohammed786]

Thanks

 

[Dannypipe]

Correct!! Click this photo and you will see how it works.

 

[Mohammed786]

Thanks alot