Is my pressure guage faulty?

[thomo2710]

Vaillant Turbomax Pro 24e

whenever i drain down my system my pressure guage does not move!!

it sits on about 1.4 bar when full and after i have drained all rads and boiler it still thinks there is 1.4 bar

When i fill it back up its guess work and i have no clue how much pressure is actually in the sysytem.

Once filled back up over the next 3/4 days it will creep at snails pace up and down a bit (not even .1 of a bar either way and stay there)

When i had the boiler serviced the guy said it was probably clogged up with crap over the years.

I have had a new pump fitted to the boiler and when the pump was off the guy fiddled with the metal clip think thats on the end of the wire coming from the guage but it still doesnt play ball.

Can guages actually go faulty? And do you think mine is or is there a blockage or switch/sensor failiure somewhere?

Thanks in advance

 

[Gasguru]

The gauge and/or the port where it connects to the boiler pipework is probably blocked. If the gauge is blocked you'll need to replace it. On the boiler side the port may need cleaning out..screwdriver/drill bit.

 

[thomo2710]

thanks gas guru,

i cant explain the connection bit to the pipe very well but the wire goes into this thin metal clip that u can turn and pull backwards and forwards but couldnt see how it came off.

just scrape around it to clean or do i need to get into it?

just filled boiler and system back up to test new pump works and been chasing air around for the last 3 hours so a bit loathsome to drain it all down again to get the pump back off to get to where the guage goes into the pipework.

no other way to clear the things?

 

[thomo2710]

http://www.clickonbathrooms.co.uk/vaillant-101271-pressure-gauge-thermometer-manometer.html

describes "that metal clip thing" better than i did!

 

[thomo2710]

can i just drain the boiler itself to take the pump back off to have a look at the guage or do i need to drain all the rads aswell?

 

[Gasguru]

Bleed all the radiators, screw the auto air vent cap shut, open the boiler drain, check the expansion vessel-see FAQs, when no more water comes out remove the clip and fix the gauge.

 

[thomo2710]

Ok all rads bled, pure water coming from then now

please confirm that:

screw auto air vent shut
the white knob is the auto air vent
http://i27.photobucket.com/albums/c197/thomo123/IMG_0409.jpg

open boiler drain
that is the little tap to the left of the filling loop
http://i27.photobucket.com/albums/c197/thomo123/IMG_0412.jpg

check expansion vessel
the plastic tube hanging down just to the left of the pump
http://i27.photobucket.com/albums/c197/thomo123/IMG_0411.jpg

does the clip just pull off? pull backwards or upwards as i noticed it pulls backwards put i couldnt pull it off (but i didnt try too hard to be honest in fear of breaking it)

also the car tyre valve on top of the pump - this should be shut tight? it came delivered shut tight but i have used it today to bleed air from pump?
http://i27.photobucket.com/albums/c197/thomo123/IMG_0408.jpg


thanks for your time gasguru


[/i]

 

[Gasguru]

Your assumptions are all wrong

Expansion vessel cap is behind the boiler on the red vessel up top.

Do NOT touch the white valve at the back on the right...thats' the safety valve.

The auto air vent cap is on top of the pump (your last picture).

Use the drain-off valves near the flow/return isolating valves.

The clip just pulls off.

You might want to consider getting someone in.

 

[Whitespirit66]

open boiler drain
that is the little tap to the left of the filling loop
http://i27.photobucket.com/albums/c197/thomo123/IMG_0412.jpg[/QUOTE]

The boiler drain is on the return pipe valve, to the left of the white knob in your first pic.

 

[thomo2710]

Your assumptions are all wrong

Expansion vessel cap is behind the boiler on the red vessel up top.

Do NOT touch the white valve at the back on the right...thats' the safety valve.

The auto air vent cap is on top of the pump (your last picture).

Use the drain-off valves near the flow/return isolating valves.

The clip just pulls off.

You might want to consider getting someone in.

think i might get my man back to change the pressure guage then!

I am just curious though and like to try to do things myself as knowledge is king (within laws of course) and i thought changing a pump and pressure guage wouldnt be such a hard thing.

I guess the hard thing to understnad is what all the connectors and valves actually are!? Once known you always know.

Found the expansion vessel valve - they hise that 1 dont they!!

What does that white safety valve do then? The service manual diagram suggests that it is the PRV as its got 15mm copper running through the wall to the outside world and thats the only pipe i have going outside! so the manual can take the blame for that assumption

Ill open that auto air vent valve then - just found the bit in the service manual which says it should be open 1-2 turns!

Drainoff valve - there is a little tap on the return pipe (similar to the 1 i linked picture too) but it has a solid end so cant see how water can escape via a piece of pipe - the only thing i could find thst had an open end was the 1 i linked a picture to to the left of the filling loop

i have been working off the diagram in Chapter 3 - 3.3 Functional Diagram

http://neighbourconstructions.co.uk/OLDWWW/PDF/Standart efficiency/turboMAX_pro_installation.pdf

Note - i dont want to be a gasman/plumber etc, i merely like to try to do things and like to learn and understand new things

Thanks gasguru

 

[thomo2710]

open boiler drain
that is the little tap to the left of the filling loop
http://i27.photobucket.com/albums/c197/thomo123/IMG_0412.jpg[/QUOTE]

The boiler drain is on the return pipe valve, to the left of the white knob in your first pic.

I thought that origianally - but its a solid end - or does the "whole end" unscrew?

 

[thomo2710]

update

pressure guage was blocked - i couldnt even get a sewing pin in it!

Replaced guage and now it moves and is working good.