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Thermostatic Radiator Valves – Plumbing Tips

– Plumberparts dot co at uk. Honest reviews and advice. Sponsored by Bing, welcome to today’s
Plumberparts dot co at uk video. Today, we’re gonna look at
thermostatic radiator valves otherwise known as TRVs. They individually control
the temperature in the room to an individual radiator. Firstly, we’re gonna have a
look at how to change them, and then we’re gonna have
a look at how they work. I hope it’s very informative. Hold tight. So, how does a thermostatic
radiator valve work, and what’s the difference between that and a normal radiator valve. Well, firstly, a normal radiator valve is just a valve that moves up and down and shuts off the flow of
hot water from the boiler into the radiator, just
like the tap on a bathtub. The main difference with a
thermostatic radiator valve is that it automatically
controls the amount of hot water going into a radiator
according to the current heat of the room that it’s situated in. There are two main types of
thermostatic radiator valve. One uses a spring that
expands and contracts, and the other uses a wax jacket
that does exactly the same. For this video, we’re gonna
look at the spring type, because they both work
in a very similar way. So, we have a spring that is made of metal that is very susceptible to
the temperature around it. If the room is cold, the
metal will be contracted because when metal is
cold, it is contracted. Therefore, the valve jumper will be open and hot water will be allowed
to flow into the radiator. If the room is warm,
the spring will expand and that valve will be pushed down and the flow to the radiator will stop. And that’s how they work. A very common problem I
have with customers is, sometimes they’ll come
in, the room is cold, the radiator, when they
feel it, blazing hot, and yet they still go to the
thermostatic radiator valve and open it up more. That’s completely pointless. The room is cold, the radiator’s hot, therefore, the thermostatic radiator valve knows that the room is cold, and it’s trying to heat it up. If you go into a cold
room and feel the radiator and it’s hot, do not touch the
thermostatic radiator valve. Only touch it when you go
into the room, and it’s cold, and you find that the radiator is cold. Also, another thing you need to consider, is where you can actually instal thermostatic radiator valves. If you have house with two
rooms, in one room you have the room thermostat, which controls the whole heating system, and one radiator. In the other room, you
have another radiator and that has a TRV on it. Don’t put a TRV in the room that has the room thermostat in it. The reason for that is,
if the TRV closes down, and the room thermostat
is not satisfied, it will never knock the heating
system off to the whole house, and you won’t get any saving. That room thermostat there
needs to have an exactly true reading of the maximum capacity that the heating system can give out. Therefore, the radiator in the
room with the room thermostat should have a lock shield
on it that is fully open. So let’s go back to the house,
and find out how you actually change a lock shield over for a TRV and really how easy they are to instal. I’m assuming you all
know how to drain down a heating system already. Finding the lowest point
in the heating system and drain off, taking your hose
outside and opening that up and making sure that the water supply is turned off to the heating system. Next, you allow air into all the radiators that you want to change in the TRVs. Generally, if you’re a
bit worried about this, let air into every radiator in the house. You should hear the air sucking. (air hissing) As soon as you see your
hose outside stop running, that should indicate
that the heating system is drained down and you’re
ready to change the valve. Let’s have a look here. As you can see, we’re removing
this old lockshield valve here, which is just an on and off valve. So, now that we know the
system is all drained down, we can loosen that off. Now’s the time just to
make sure that the water has drained out of the system. As you can see it has. And then we can loosen off
the 15 mil pressure fitting on the bottom. (metal banging) As you can see, our new
TRV isn’t going to fit on this current radiator insert. All new TRVs are supplied
with a new insert, so this one here will need removing. There are special tools to do this. You can have a hexagonal
tool that goes in like that, a square tool, a lug tool cut in here. This is quite an old one as you can see. Today I’m gonna use this
one here because we’ve got hexagonal fitting on there. Now often you can just lift
out and it may get out. But generally, you’ll have
to just put the spanner on like this and then
wind it out like that. (metal banging) There’s the old insert out, and that’s the old valve
completely removed. Now we need to PTFE this thread. Do that by having the
PTFE on there just hold it with your thumb and wrap it round like so. Do that about 10 times I’d say. Insert into the radiator and then tighten up. (metal banging) The old nut and olive on here
should still be fine to use. But if you’re not happy, you
can just pull the nut off and use a pair of grips
to pull the olive off. But today what we’re gonna
do is just wrap a small amount of PTFE around the
olive to ensure a watertight seal on the bottom of our new valve, and then we’ll apply our new valve. Once you’ve wrapped the
PTFE around the fitting we are ready to push the fitting back on, tighten up that bottom joint first, lift this up into here like so. (metal banging) Tighten that up like that. Remove the top cap, and that will show the actual valve jumpers. You see that moves up and down. Put the valve to five so it will go on. There you go. You have now a working TRV. I hope you found today’s
video informative, and that we’ve given you an idea
about how a TRV works and how to instal it. If you need anymore help
or anymore information, or you feel you’ve missed
something out, do let us know through our channel. And as ever, favourite and subscribe. Have a lovely day and I’ll
see ya’s laters, hold tight. Plumberparts dot co at uk. Honest reviews and advice. Sponsored by

  • Never use a thermostatic head vertical, heat from under wil it make close faster than it normally should do.
    En why are people grips so much instead of 2 spannners?
    Grips will damage your valve and there is no need to do that. Use 2 spanners al the time!

  • We just have a thermostatic valve and lockshield installed but the radiator is cold. How do I turn on the radiator with the new type lockshield?

  • Great video. Very informative especially the part about not fitting a TRV to radiator in the same room as main thermostat. Many thanks.

  • First thing i noticed is that the installation of the TRV is not optimum and it's a basic mistake made by 90% of plumbers installing TRVs. The TRV should be mounted in the horizontal, not vertical, as recommended in the UK HVCA DOMESTIC CENTRAL HEATING INSTALLATION SPECIFICATION. This reduces the impact of heat gain from the pipe and gives a more accurate reading of room temperature by the valve sensing head. On the Vertical, the sensor head can be 6-10°C above space temperature due to heat gain from piping, as opposed to approx 2°C if it was mounted in the horizontal. In otherwords, the valve senses 27°C in the room, when its actually 20°C.

  • Thank you! I live in the US and have Myson radiators on a boiler system. The system was not installed with TRV's in each room and I would love to have them. Do I just need to make sure there is a bypass before I install these so the hot water will continue through the rest of the zone? This sounds dumb but nobody here knows anything about this system (it was brought here and installed by the previous owner who was from the UK) when I call any professionals they have no idea…

  • How important is it to fit the TRV to the inlet side of the rad and is it essential that the arrow cast on the TRV body follows the water flow? I'm looking at a Draytron TRV4. Many thanks

  • Brilliant video, just swapped out 2 valves for TRVs today following your instructions, super easy when you know how, cheers!

  • Hi my hot water in is in the bottom of the radiator as in this video but some people say we need to place it upside of the radiator to make it work efficiently because the heating air rises up so if the valve is placed up the heating air will rise up and valve will get the real temperature then. What do you think?

  • Would keeping a TRV fully open in the same room as the stat be of any benefit, or do you still recommend converting to a lockshield? Ta muchly

  • great, useful vids.
    I recently moved into a house we're the only radiator not to have TRV is in the bathroom.
    Our thermostat for the boiler is a wireless one.
    your video says you shouldn't have a thermostat in the same room as a radiator with a TRV, I do understand the reason behind this.
    At the minute I got the thermostat in the living room with the TRV set at 5 (max) to try and leave the radiator open and stop any interference with the radiator switching off before the thermostat is up to temp. but i do think sometimes the radiator shuts off before the thermostat is up to temperature, also I'm finding is the bedrooms don't seem that warm which are all set to 3.
    Any suggestions of any other way around this, there isn't a radiator in the hallway.

    Also the TRV's are labelled 0 – 5, is there a set standard of number to room temperature

  • Great video must get the wife to watch this ,i have explained til ime blue in the face,she just will not leave the bloody things alone. she has been married to me for 41 years ,yes ime now 70.retired old school plumber,but will she learn not in a millions years women.

  • With the rad in the hall with the the room thermostat you said locksheild fully open? What about the other side the manual valve with plus and minus? I don’t think my locksheild has ever been fully open only about half a turn thanks

  • Links to the tools I use everyday here:

    Plus, follow my Vlog “TimesWithJames”:

  • Great vids and advice mate. Question: how do I line up/bend the copper pipe to the trv when its slightly out by a couple of millimeters? Thanks!

  • Thanks great vid clear and informative, just what I needed. I wasn't sure the TRV would fit into the same space as The old type valve, but now I see how it's done. Just one question please ? can I use the old nut on the feed pipe or do I have to remove the old one and it's olive ? cheers…. Chris.

  • You seem to have forgotten the problems with TRV , 1. don't ever fit if you have long drapes, 2, don't fit if you have a settee in front of the rad ,3, don't fit if you have a radiator cover, and don't fit to every rad encase your boiler has an over run on it .. don't forget to mention to keep the cap to shut the trv completely off if you decorating a room in cold weather.. and want to remove the rad…

  • Keep trying you will learn the trade eventually, almost there young man .. a few more years of studying and you will get there. 7 out of 10 for effort . but do try harder …

  • I am installing a new radiator. However, the new radiator has a 25mm thread and the heating system is 15mm. Can you get a 15mm – 25mm TRV?

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