Gaothfar Awaiting Email Confirmation
#1

Hi,
Can I just buy a TRV (thermostatic radiator valve) and fit it to my rad where the existing connection is? I know I will have to drain the system but wonder if the connections on the TRV are the same as the existing ones. I was thinking of buying the Myson one which is only about €7.
Thanks

ART6 Subscriber
#2

Should be a standard fit. The rads are generally all the same.

Twiggy69 Registered User
#3

Hi Gaothfar,
Not trying to hi-jack your thread, but I have the same job to do, I believe I have to replace 4 TRV's. Could you give me an idea where to get advice on how to tackle this job???

Gaothfar Awaiting Email Confirmation
#4

Replace? Do you have them fitted already? I found a thread on this site which explains how to get faulty TRVs working again.
In my case, I'm hoping to put them in those rooms which aren't used regularly during the winter and keep them turned down low.

Twiggy69 Registered User
#5

Yep, I've to replace the originals Myson's I fitted in 1993. They have been fine, but as we had the heating turned off over the summer, when we fired up the boiler, it only heats every other rad ,i.e. one hot,one cold, one hot, one cold etc

I had a plumber call in who recommended replacing 4 TRV's. To-night he arrived back and recommend I change my internal kerosene boiler for an external model - ballpark €4,500 !!!

Before I take this plunge, I intend to replace the 4 TRV's, flush out the system & see how the system operates. If that fails, I'll sell my soul for the new boiler!!!

Even before I take on with replacing the TRV's I would be interested in hearing about reviving faulty TRV's. Any links would be much apprecaited.

Regards,

T

IRISH RAIL Registered User
#6

Just buy some new heads for them and swap them over

Gaothfar Awaiting Email Confirmation
#7

Hi Twiggy,
Somewhere on these boards there is information on how to free TRV heads with WD 40 and a vice-grips. I haven't time to search for it but I'm sure you'll find it if you search.
Alternatively, I'd do as Irish Rail suggests and replace the heads - they're not expensive.
Can I suggest that this is no time to be buying a new boiler.
I'd take my time there and research alternatives.

Twiggy69 Registered User
#8

"Can I suggest that this is no time to be buying a new boiler.
I'd take my time there and research alternatives."


Hi Gaothfar,
I am intrigued by your comment above, I take it you are alluding to renewable alternatives. Any thoughts or pointers would be appreciated.

I will also look up the thread re the rad valves releasing, however, replacing the plastic controllers is not the answer, as the needle that controls the valve is part of the plumbing fitting attached to the rad.

Thanks for the advice
T

JamesM Registered User
#9

Twiggy69 said:
" I will also look up the thread re the rad valves releasing, however, replacing the plastic controllers is not the answer, as the needle that controls the valve is part of the plumbing fitting attached to the rad.


The "needle" sometimes sticks down after being off for the summer. Gentle tapping on the top usually frees it and it pops up on a spring.

Depending on where your boiler is, €4500.00 seems a lot for a boiler in a cabinpac. It does depend on how much pipe-work is involved. A modern indoor kerosene boiler will be more efficient than a boiler outside, because there will be very little heat loss with no pipes running underground out to a cabinpack or boiler house.
Jim.

derickmc Registered User
#10

Hi,

This is probably a stupid question but I have been advised to install thermostatic radiator valves to improve the energy efficiency of my house.

Are TRV's just regular valves i.e. with a random scale of 1 to 5 on them or are they something much more advanced i.e. like a cylinder stat where you can set an exact temperature to be heated to ?

Thanks,
D

youtheman Registered User
#11

derickmc said:
Hi,

This is probably a stupid question but I have been advised to install thermostatic radiator valves to improve the energy efficiency of my house.

Are TRV's just regular valves i.e. with a random scale of 1 to 5 on them or are they something much more advanced i.e. like a cylinder stat where you can set an exact temperature to be heated to ?

Thanks,
D


TRVs are supplied in two basic components:

1. a valve that replaces the existing valve. Your original valve is twist to close (3 or 4 full turns typically). The TRV valve is spring loaded, and the spring opens the valve (this is important to know if you ever want to manually close the valve).

2. a thermostatic head that contains a wax that expands/contracts with varying temperature (same principle as the thermostat in your car). As the wax heats up it expands and pushes the spring loaded valve closed, as it cools it contracts and allows the spring to open the valve.

I have them in my upstairs bedrooms as the literature supplied recommends a set temp. of 18 degrees (this is 2 on the 1-5 scale). So the number 1-5 corresponds to a set temp.

They recommend that the TRV head is as far from the radiator as possible (so that it senses the average room temp rather than the air immediately beside the radiator). So mine are installed horizontally (you can fit them either way). You can also fit them on the inlet or the outlet of the radiators, so mine are on the side closest to the middle of the room (avoid putting them behind furniture if possible, for the same reason).

If you were thinking of putting a TRV on every radiator in the house then you'd have to install an automatic bypass valve (in case they all close automatically together). My new condesning boiler has this bypass valve fitted internally.

My TRVs cost less than €20 euros each, well worth it I reckon.

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derickmc Registered User
#12

Cheers youtheman, I didn't realise that the TRV's took the temprature from the room and not from the rad itself.

Would I be right in saying they behave in more or less the same way as room stats then ? except room stats send a message back to the boiler to stop burning while the TRV just closes the and prevents the hot water from entering the rad.

Is there anything distinctive about TRV's to look at? I have valves on a number of rads with 5 settings. However the system is oldish, I have the house 5 years and the system was in place before that so I am presuming they are not TRV .. However you don't need to turn them several times to open or close them like regular old radiator valves either so I am not sure ..

youtheman Registered User
#13

The objective of any heating system is to increase the air temp to x degrees, and (hopefully) hold it there. So the TRV is designed to sense the air temp, and open/close the radiator valve to maintain it. If all the TRVs close then the boiler return temp will rise and the boiler will eventually cut out. So you could, in theory, have just TRvs and no room thermostat (but I wouldn't recommend it).

The TRV head is approx 2" diameter and 4" long, so it should be easily recognised. If you look under the plastic TRV head you should have a thread that you can unscrew with your hand to remove the TRV head, the valve will then have a small spindle that you should be able to push in to sense the spring pressure against it. If you put a hair dryer on the TRV head (in your hand) then you should be able to see the end move down as the wax inside expands.

I came across the following link which shows various recommendations for heating controls :
http://www.heatingcontrols.org.uk/Site/downloads/TACMAGuide.pdf

If you are used to looking at control diagrams then you may find it handy. I have System N.o 13 without the actuated valve on the inlet to the hot water cylinder (or the cylinder stat). So I have the boiler with the bypass valve built in, a timer, room thermostat (downstairs) and TRVs upstairs. Note the bypass valve in the circuit, and the fact that TRvs are not fitted to all radiators. It would be pointless putting a TRV in the same room as the thermostst as they would bascially be working against each other.

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Gaothfar Awaiting Email Confirmation
#14

You the Man

Mark0d40 Registered User
#15

Guys just registered but having issues with these badboys.
My whole house (newly extended and old cottage) have trv's on every rad, however I have thermostatically controlled wood stove (with back boiler) that when on and reaches temp pushes the heat supposedly around the rads. It seemed to work fine at the start but now most rads don't heat up, some do some don't, shall i just get them taken off? As in the summer we have solar but winter the stove is on and we want house warm, unlike traditional heating methods we don't need to lower temps as much, rather on or off will suffice.
sound like the trv's are the issue? i will take advice and tap them all to check they are released, I have bled every rad for gallons at this stage no joy with some rads
thanks
Mark

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