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TRV - thermostatic radiator valve

  • 01-10-2008 1:57pm
    #1
    Closed Accounts Posts: 31


    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


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Comments

  • Registered Users Posts: 2,632 ✭✭✭ART6


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


  • Registered Users Posts: 258 ✭✭Twiggy69


    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???


  • Closed Accounts Posts: 31 Gaothfar


    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.


  • Registered Users Posts: 258 ✭✭Twiggy69


    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


  • Closed Accounts Posts: 1,097 ✭✭✭IRISH RAIL


    Just buy some new heads for them and swap them over


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  • Closed Accounts Posts: 31 Gaothfar


    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.


  • Registered Users Posts: 258 ✭✭Twiggy69


    "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


  • Registered Users Posts: 1,775 ✭✭✭JamesM


    Twiggy69 wrote: »
    " 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.


  • Registered Users Posts: 66 ✭✭derickmc


    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


  • Registered Users Posts: 1,265 ✭✭✭youtheman


    derickmc wrote: »
    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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  • Registered Users Posts: 66 ✭✭derickmc


    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 ..


  • Registered Users Posts: 1,265 ✭✭✭youtheman


    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.


  • Closed Accounts Posts: 31 Gaothfar


    You the Man


  • Closed Accounts Posts: 2 Mark0d40


    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


  • Registered Users Posts: 1,265 ✭✭✭youtheman


    Mark,

    I can't tell from your query exactly how your system is configured, but I'd recommend some basic fault finding.

    1. turn all the radiator TRVs to max temp (i.e. configure them to be fully open).

    2. wait until the heating system is stone cold, then turn on. The water should heat up, the TRVs should be fully open (because the air temp. is below the set point) so your radiators should heat up. If after 10-15 minutes, the pipes are hot but the radiators are cold then it would tend to indicate a TRV problem. It could be the valve or the head (see step below)

    3. Unscrew the TRV head from the valve. There is now nothing to hold the TRV valve closed, the spring in the valve should open it and your radiator should heat up. If Step 3 works then it suggests the TRV head, if Step 3 fails then it suggests the TRV valve.

    When I installed my TRVs some of them didn't initially work so I had to remove from the wall, take into the back garden and flush with a garden hose. My experience (so far) is that the TRVs don't like gunk in the water.


  • Closed Accounts Posts: 2 Mark0d40


    thanks youtheman - a very fitting moniker, I should say I have removed the control knob, form maybe 5 rads and as our system is wood only, we have no heat in the system for half a 24 hour period anyway, we don't get fire on until about 4pm, so from that perspective yes I start from cold.
    So despite that I still see no marked improvement.

    The one thing I can say is ther eis a build up of heat and the foot of every pipe, almost waiting to get into the rad, below the TRV so it does seem as thought the TRV is the problem, this is with and without the temp control knob.
    thanks


  • Registered Users Posts: 1,265 ✭✭✭youtheman


    Mark,

    1. make sure the manual valve on the other end of the radiator is at least partially open, maybe open it fully (but remember how many turns it took, so that you can restore it afterwards).

    2. remove the TRV head (just unscrew). Try pusting the pin head in and out a few times (to make sure the spring is not stuck). They should fail open, with the pin out, but maybe they are stuck closed. If there is some gunk stuck under the seat of the valve then this might help move it.

    But if heat is gettin to, but not through, the valve then you might be better replacing them. They're not expensive, less than 20 euros each. I got three separate types before I decided to use 'Heatline'.


  • Registered Users Posts: 2,409 ✭✭✭sullzz


    hey mark , the rads that dont heat try removing the trv head and press the pin on the valve itself as sometimes these stick down if left closed for a long period of time if stuck hit the valve with something th free the seating , also check that the head is closing by turning it open and closed and making sure the inner part is going up and down, if all is fine with what i have just said you probably need to balance your system


  • Registered Users Posts: 161 ✭✭Pope John 11


    Does anyone know where is the best place to buy TRV's. I checked B&Q yesterday & they cost €30:eek:.

    I assume this is expensive....hoping to find a place that is open today if possible.


  • Closed Accounts Posts: 31 Gaothfar


    I paid €13 or thereabouts in Cahills of Gort a few months ago.


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  • Registered Users Posts: 161 ✭✭Pope John 11


    Thats good....could you deliver one to me in Dublin


  • Closed Accounts Posts: 31 Gaothfar


    Just found the box. The brand is Danfoss and they were €14 each.
    And Pope John Eleven, how do you get into Dublin? Is there public transport?


  • Registered Users Posts: 1,265 ✭✭✭youtheman


    I paid €9.95 each, plus VAT at 21%.

    I bought three different types before I settled on Heatline units.

    I was looking for Danfoss units but couldn't find them in Cork.


  • Registered Users Posts: 533 ✭✭✭chuck eastwood


    Hey lad's. couple of quick question's. Just moved into a house with a bog standard heating system. I'm going to put a digital thermostat in along with a new timer.I also want to fit TRV's but should i put them on the inlet or outlet on the rad's .Its a gravity fed system so i'm wondering what auto by pass should i put on the system to protect the pump. Any help would be great


  • Closed Accounts Posts: 672 ✭✭✭items


    I have my suspicions over TRV's due to their location, TRV's are fitted at pretty much a cold area, bottom area of rad is where cold air is drawn / pushed to rad, as rads heat by convection, cold at bottom hot out top. Many people brought this up with TRV manufacturer and to get over it, some TRV's are supplied with extra option of a movable sensor, its just a small box, box reads room temp and sends information back to needle control at rad valve through a metal type cable. The box is still fitted in a suspicious area as the cable is not long enough to locate at ideal area.

    Fitting a house with TRV on all rads can be expensive compared to very little if not any benefit gained. I would sooner use cost of TRV to go towards fitting more room stats and breaking system down into more zones.

    If heart set on TRV's have them fitted to flow pipe, most TRV's can be fitted on either flow or return but I find when TRV's are fitted on returns, balancing system can sometimes be a nightmare as no control over restriction part of balancing.

    I find best energy efficient results is to break heating system into zones, living /dining areas, sleeping areas, kitchen / utility areas, halls and landings etc. Each zone is controlled by room stat fitted in a proper area, away from windows and doors, stats controlling motorized valves, as room reaches set temp stats will shut off motorized valves, when room temp drops stat calls for more heat, motorized valve opens. This way I know heating to rad is coming on or off depending on room temp. With TRV's I've no idea whats happening, slightest thing like a curtain can throw a TRV off, thats if they even work at all.

    When you buy a TRV you'll notice written on box, TRV may turn rad off when room temp matches TRV setting, In all my days working on heating systems, I've never once found a rad with TRV fitted being off while room was roasting, cant even remember finding a rad with TRV fitted being a different temp (cooler) than any of the other rads in same house fitted with TRV's.

    I've always wanted to take some readings of rads fitted with a heat sensor and try to work out if they do actually work but its almost impossible, instead of wasting time trying to figure out if they do work, I just dont use them. Each to their own I guess.

    About the by pass, just leave one rad without TRV, smallest one like bathroom even en suite if fitted.


  • Registered Users Posts: 533 ✭✭✭chuck eastwood


    Thanks, i was thinking the same thing about the trv's. but it would be a nightmare to zone this house. The reason i thought about putting them on is that i have 3 of the existing valves leaking so while i drain the system i wanted to do as much work on it now as i can. would you be able to give me a few tips on balancing the system ?


  • Closed Accounts Posts: 672 ✭✭✭items


    The first Thermo type valves I ever fitted were for hot water control @ cylinder, these type of thermos do work as I can tell by feeling pipe after TV to feel if water is hotter or colder. These TV's work because sensor is in direct contact with cylinder heat, just have my doubts over TRV's because that small sensor located inside TRV head is not really in contact with anything only air, all sorts of things can obsure the air reading as mentioned above, curtians, kids toys, location of valve etc. After first thermo type valves started to work, I think everyone else jumped on band wagon.

    Having said all that, its just my opinion, the big wigs and such find they do work, as far as I know I think grants are given in some form to up date heating by use of TRV.


  • Registered Users Posts: 8 baldeagle


    I'm looking to get programmable TRVs so that i can 1) split the house into more zones (simple TRVs would suffice for this, i know) but also 2) to regulate different temps at different times of the day in the different zones.

    Example, I only want to heat the bedroom after 21.00 in the evening while the downstairs sitting room should be heated from 18.00 to 22.00 (just rough times as an example).

    Anyone know where i can purchase such Programmable TRVs?

    This is what i'd be looking for 'Honeywell HR40' http://europe.hbc.honeywell.com/products/pdf/en0h0243-ge25r1001.pdf

    Thanks


  • Registered Users Posts: 533 ✭✭✭chuck eastwood


    you can get them here. I have bought gear from these guys before. Those trv's are about 50 bill's each. Lot of money but if your only putting them in one or two room's.Take you a hell of a long time to make your money back

    http://www.heatingcontrolsonline.co.uk/thermostatic-radiator-valves-c-28_37.html


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  • Registered Users Posts: 8 baldeagle


    Thanks Chuck,

    Found this link for a site in Germany. Less than a tenner for P&P so may just go with them as they have the Honeywell HR40 that i'm after (my dad's got those and hasn't had a single issue). Also, the HR40 is compact and easy to use/prog. I've seen other models were it's over complicated to prog and/or bulkier than the HR40.

    Only question remains now is if the German rads/pipe dimensions (my dad's in Germany) are the same as in Ireland. I believe they are, but will report back if/when I found out.

    http://www.fairtrader24.com/xtcommerce/product_info.php?info=p3_Honeywell-Raumtronic-HR40-elektronischer-Heizkoerperthermostat.html


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