HOW TO PULL A VACUUM – Apprentices – Quick TRV change – Plumbing Tips

Posted on: January 2, 2017 by in Plumbing Videos
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HOW TO PULL A VACUUM – Apprentices – Quick TRV change – Plumbing Tips

How to pull a vacuum on a F and E or gravity fed heating system. Great for quick TRV, radiator valve changes and small jobs where draining the whole system can be problematic. Plus it will save you a bunch on inhibitor! This video is not for your average DIYer, more for the proper plumber and apprentice looking to learn, so don’t try this at home!




– Hey if you’ve been
lucky enough to stumble
across this video,
all about how to quickly
change a radiator valve over,
then great, we’re gonna
get to that any minute now.
Before you do, please
click on one of the cards
that’s appearing right
now, they’re available
throughout the whole of the video,
to subscribe to our channel.
We do lots of photos, lots of videos
of plumbing disasters all the time,
and you’re gonna love it!
So we’ll see you there.
Anyway, hope you’ve enjoyed
this video, hold tight.
I suppose you’re here to
learn about how to change
one of these radiator valves
real easy, real quickly.
Well let’s get down to it, hold tight.
– [Voiceover],
home of Find Your Plumber.
– So this video is a little bit naughty,
because I’m going to be
telling you how to do something
that maybe you shouldn’t
need to know how to do.
But sometimes, it’s actually easy
to change a little radiator
valve like this one here.
You just have to slap this knot off
and this knot off without
actually having to drain
the whole heating system down.
Now, on a gravity-fed heating system,
we call that pulling a vacuum.
And it is one of those
things you only do on a job
where you’ve only got a
very quick little bit to do.
It’s not like when you
change a radiator over
and doing a lot of part work.
It’s for actually doing just
little valve changes like this.
Quick and easy.
And the pros of doing this is
means you don’t have to drain
the whole heating system out,
which obviously saves you time,
but it’s also saves the
customer from having to put
another tub of inhibitor in.
Sometimes you get away with it,
although on this job here,
I’m always going to top that up.
I always have so many tubs
of inhibitor in the van.
Just a good idea,
whenever you do any work,
just to pump a little bit in anyway.
So then, what is a vacuum I hear you ask.
And I’m kind of already
while we’re doing this video
coming back to the idea that really,
this is just going to be interesting
for those of you who are
plumbers or apprentices,
not so much for your normal DIY,
because personally, I don’t
recommend they do this.
You need to have real good
knowledge of heating systems.
You need to have a good idea
of how to use all the equipment
how to rug out, and
all that sort of stuff.
And it’s very important that you’re quick,
because sometimes the vacuum can break,
and sometimes you do that
and you’ve got a three-story
house on top of your water.
It can be a bit bum-knippy,
put it that way.
Especially when you’re an apprentice.
So anyways, a quick demonstration
about what a vacuum is.
Imagine we got this straw here, okay,
and we’ve got a glass of water like this.
Now the top of the straw is if
you’ve got an F and E system,
so imagine there’s a
tin cup here at the top
and also a little expansion
pipe going in there,
the little vent pipe.
If we’ve got a system
that’s full of water,
so like that,
if we don’t bung the
expansion or the F and E tank,
which is what we’re
going to do in a minute,
when we start draining out,
you’ll notice the water comes
out straight away with that,
just falls out.
Which means, if you’re
going to take anything off,
like a radiator valve
or anything like that,
then that water’s going
to come out as well.
You’re going to have heating
systems throughout the water,
radiators, everything’s
going to be coming out.
You’re going to have be
like Ayrton Senna
to be able to get that off that quick.
Put it back on without
cracking a bit from problem,
especially if you’ve
got an old sludgy system
or something like that,
black water everywhere
doesn’t make a happy customer.
So let’s say, that we do
bung our own expansion pipe
and our F&E pipe.
Now I’ll do that by just
popping my finger over the end.
So we gonna pop her in
here just like that,
pop our finger over the end like so,
and then when we drain the system out,
you see that, all that
water stayed in the system.
If the bung breaks, and the vacuum breaks,
“blop”, like that, and that’s a whole
heating-systems’ worth of water.
So now we’re gonna pop up into the loft
and bung the system
and basically get it ready
to put a vacuum on it.
Steven! Can I borrow
your steps mate? Cheers!
Alright, so up in the loft,
this is the sort of thing
we need to look for.
So we found our tank,
there’s our expansion pipe
and there is our vent pipe or
whatever you want to call it.

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