Testing mains pressure

[abloke]

Hi all. I want to install a cylinder and conventional boiler, and replace the tank in the loft with an expansion vessel. I dont know what makes to buy yet so I wondered if there is a general ideal incomming mains pressure required for good operation of such a system and how can I test this myself. I dont mind buying equipment. Thanks in advance

 

[LUNAT]

HI

generally you can test without any equipment.
1.open stop tap full,open cold water tap a the sink full.
try putting your hand to stop the water. can you stop it ?
if you cannot stop then it means there is enough pressure.
2.open sink,bath,basin cold taps together .if water comes out
from all taps at a reasonable force then pressure is O.K

 

[andytheplumber]

The pressure is irrelivant You need to test the flow rate You need a proper gauge for that. You can have hardly any flow rate and lots of pressure. If you stick your thumb over a tap the pressure will build up and seem good.

 

[kevplumb]

so you fill a bucket and time it

 

[WDIK]

Hi all. I want to install a cylinder and conventional boiler, and replace the tank in the loft with an expansion vessel.

ok please explain what you really mean.


do you mean the hot water header tank?

 

[Trouble666]

A weir gauge is the correct piece of kit you need; Without sounding rude, it is quite self explanatory; Just put it under mains press. i.e CW tap, and it'l indicate the pressure of the incoming mains water

Hope that helps
Regards

 

[wiggikins]

A weir gauge is the correct piece of kit you need; Without sounding rude, it is quite self explanatory; Just put it under mains press. i.e CW tap, and it'l indicate the pressure of the incoming mains water

Hope that helps
Regards

A PRESSURE GAUGE MEASURES PRESSURE

A WEIR GAUGE MEASURES FLOW.

 

[abloke]

Thanks for the help chaps. I cant get my head round the idea of loads of pressure and no flow rate. Does it mean you can have a dribble of water but enough pressure to disperse a crowd of Poll Tax rioters?

Anyway, if I test flow with a weir guage and pressure with a pressure guage what are ideal readings to look for. I guess pressure is measured in bar, but what's flow measured in?

Thanks again everyone

 

[simond]

Q. If you had an open end of pipe from the water main stopcock wide open with water gushing out, and stuck a pressure gauge on the end, what would you get?

A> it would measure the static pressure, eg: 2bar.

Q. If you take the same piece of pipe, but turn down the stopcock to the minutest dribble, and then stick the same gauge on the end, what will it read?

A> After a short period of time, the same, 2bar.

However, if you measured the flow from the pipe with the stopcock open and nearly closed you would get very different readings.

In this way the static pressure reading for a property is not a reliable indicator of performance. It is the 'flow rate' that will primarily decide whether an unvented cylinder will be useful.

 

[megawatt]

A good and clear explanation of this.

 

[Softus]

generally you can test without any equipment.
1.open stop tap full,open cold water tap a the sink full.
try putting your hand to stop the water. can you stop it ?
if you cannot stop then it means there is enough pressure.
2.open sink,bath,basin cold taps together .if water comes out
from all taps at a reasonable force then pressure is O.K

View media item 216

 

[wms]

turn tap fully on take a one litre measuring jug. time how long it takes to fill then divide into 60 seconds this will give you the flow rate per minute its not exact but will give you a rough idea

IE jug takes 5 seconds to fill. 60seconds divided by 5 seconds time to fill the jug, equals 12 this gives you gives you a flow rate of 12 liters per minute no special tools needed.only a jug and watch

 

[Softus]

Are two jugs always better than one?

 

[wms]

 

[abloke]

Just want to say thanks to you all before this thread becomes Benny Hill-esque