Plumbers and Heating - Should I leave the TRV off one Radiator in the house?

sho_me_da_money

Firstly just want to say thank you to everyone that commented here. I think we'd all agree that Bendy's comment is like the Mona Lisa equivalent on this thread. Absolutely quality detail and I appreciate the time you have taken to write your response.

I suspected the same Bendy - when a radiator is oversized for its space, the lockshield could be leveraged to make it "weaker" than its original spec.

Sidenote 1 - I measured the space in the small hallway (1.3M (W) x 1.4M (L)x 2.3M (H)) and calculated the BTU (using an online calculator) should be around 2400-2600. All the new radiators I have bought are the Stelrad soft-line deco model (bar the living room) and I wanted the hallway radiator to match. The first hurdle was getting the right dimensions as the current 1980s radiator size was 400 x 700. The problem was that the softline deco line with closest dimensions was 600 x 600. The K1/Single Convector at these dimensions only outputted around 1700 BTU. Anything smaller in dimensions and the BTU was even lower. My only option was to go for a K2/Double Convector at 600 x 600 with a BTU output of around 3400. I figured more would be better than less and if needed, I could control power of that oversized rad with the lockshield by making it "Weaker"

Now one detail I missed out in the above, I configured my heating with a Netatmo smart thermostat. During black Friday, I purchased 3 x Netatmo Smart Valves (TRV) but I have not installed any of them yet. As much as Id like to replace my living room TRV, it simply looks aesthetically horrible - a big white TRV on a anthracite radiator vs a a slick chrome and anthracite TRV.

Given the new detail (re:smart valves) does anything in your above message need to change please Bendy? 

Sidenote 2 - I noticed the radiator that warms up the fastest are kitchen and the upstairs bedroom and bathroom. The boiler is located in the kitchen with the pipework going into the ceiling. Above the ceiling is the bedroom and next door is the bathroom. For these reasons I can understand why the kitch, upstairs bathroom and bedroom warm up the fastest. Strangely I think the living room is the last radiator to warm up in the entire house.

FreeBear

sho_me_da_money said: Sidenote 2 - I noticed the radiator that warms up the fastest are kitchen and the upstairs bedroom and bathroom. The boiler is located in the kitchen with the pipework going into the ceiling. Above the ceiling is the bedroom and next door is the bathroom. For these reasons I can understand why the kitch, upstairs bathroom and bedroom warm up the fastest. Strangely I think the living room is the last radiator to warm up in the entire house.

When balancing radiators, you would normally start with the radiator closest to the boiler, then work your way along the system. The last radiator to be balanced will be the one furthest away and slowest to heat up. It may take a few attempts to balance the system properly.

Bendy_House

sho_me_da_money said:

Firstly just want to say thank you to everyone that commented here. I think we'd all agree that Bendy's comment is like the Mona Lisa equivalent on this thread. Absolutely quality detail and I appreciate the time you have taken to write your response.

I suspected the same Bendy - when a radiator is oversized for its space, the lockshield could be leveraged to make it "weaker" than its original spec.

Sidenote 1 - I measured the space in the small hallway (1.3M (W) x 1.4M (L)x 2.3M (H)) and calculated the BTU (using an online calculator) should be around 2400-2600. All the new radiators I have bought are the Stelrad soft-line deco model (bar the living room) and I wanted the hallway radiator to match. The first hurdle was getting the right dimensions as the current 1980s radiator size was 400 x 700. The problem was that the softline deco line with closest dimensions was 600 x 600. The K1/Single Convector at these dimensions only outputted around 1700 BTU. Anything smaller in dimensions and the BTU was even lower. My only option was to go for a K2/Double Convector at 600 x 600 with a BTU output of around 3400. I figured more would be better than less and if needed, I could control power of that oversized rad with the lockshield by making it "Weaker"

Now one detail I missed out in the above, I configured my heating with a Netatmo smart thermostat. During black Friday, I purchased 3 x Netatmo Smart Valves (TRV) but I have not installed any of them yet. As much as Id like to replace my living room TRV, it simply looks aesthetically horrible - a big white TRV on a anthracite radiator vs a a slick chrome and anthracite TRV.

Given the new detail (re:smart valves) does anything in your above message need to change please Bendy? 

Sidenote 2 - I noticed the radiator that warms up the fastest are kitchen and the upstairs bedroom and bathroom. The boiler is located in the kitchen with the pipework going into the ceiling. Above the ceiling is the bedroom and next door is the bathroom. For these reasons I can understand why the kitch, upstairs bathroom and bedroom warm up the fastest. Strangely I think the living room is the last radiator to warm up in the entire house.

Was the Mona Lisa ever completed? Because my post certainly wasn't - FB has filled in a further important detail.

Cool - you do understand what's going on. :-)

Sidenote 1 - Yes, over-sizing new rads is actually a 'good thing' as you can get the same heat out as the old (smaller) rads with a lower water temp = economy savings due to better boiler efficiency. So, yes, if you have a choice, you do as you've done - larger rads, tweaked down.

Sidenote 2 - yes, that's also part of the balancing process, taking into account the greater flow pressure nearest the boiler, as FB says.

The living room rad - where is this located relative to the boiler? Anyhoo, the good news is that you can have your neat anthracite valves because it won't have a TRV. Instead, it'll effectively have two 'lockshield' valves, one which is tweaked to balance the rad, and the other which is used to turn the rad up and down - that's what I have on mine; two small neat anthracite manual valves. (In reality, the 'control' valve will also be just left unadjusted once set, and the room stat will do then do the work.

Smart valves - I take it these are controlled remotely by the Netatmo? These sound ideal for the bedrooms as you can programme them to be off during the day, and only come on morns and late eves for example. BUT, the same thing about 'balancing' applies - ALL the rads should ideally be balanced, and then the TRVs, smart or no, can do their job.

sho_me_da_money

Question - why does the radiator in the living room needs to be moved to the highest setting (5) when the TRV is replaced? The desired temperature is achieved at a setting of 4.

Am I right in saying 21 degrees isn't hit faster by moving from 4 to 5? Meaning, I could turn the valve to the 4 position, remove the TRV and away we go?

To answer your question about where is the living room located in relation to the boiler. Its the very next room - basically wedged in between the small hallway space and kitchen. However the piping on the boiler suggests the water goes UP to the ceiling, bedrooms, bathrooms and flows back downstairs. The only thing that throws that theory out of the water is that the kitchen radiator gets hot RAPID.

Bendy_House

sho_me_da_money said:

Question - why does the radiator in the living room needs to be moved to the highest setting (5) when the TRV is replaced? The desired temperature is achieved at a setting of 4.

Am I right in saying 21 degrees isn't hit faster by moving from 4 to 5? Meaning, I could turn the valve to the 4 position, remove the TRV and away we go?

To answer your question about where is the living room located in relation to the boiler. Its the very next room - basically wedged in between the small hallway space and kitchen. However the piping on the boiler suggests the water goes UP to the ceiling, bedrooms, bathrooms and flows back downstairs. The only thing that throws that theory out of the water is that the kitchen radiator gets hot RAPID.

Assuming all the control valves are open - eg TRVs at 4 or 5 - then any rad which heats up noticeably faster than the others is clearly unbalanced. Ie, its lockshield is too far open. It gets too much flow. It steals flow from the others. It's a very bad radiator.

Any rad which is slower to heat up, or struggles to do so, is likely to be suffering the opposite problem.

That's 'balancing'.

However, before messing with TRVs, make sure you note exactly where each one's starting position is.

All the rads with TRVs are capable of controlling their own heat output automatically. You set them to whatever temp that room requires - crudely, '2' will be around 18oC, '3' 20o-odd etc, something like that. As the room temp is reached, the TRV head starts to shut off the valve. You can actually feel this as you turn the TRV head; it gets stiff as you close it off - this is the point at which is actually starts to close off the valve.

As you say, opening the TRV from 4 to 5, where 4 is already waaay above 21oC (I think...), shouldn't make any difference to how quickly a room heats up to 21oC. When the room temp is at, say, 20oC, it doesn't matter whether the TRV is at 4 or 5 since both positions mean the valve is fully open. You will find the TRV is 'loose' at both these positions, which indicates that the valve is fully open, and only starts to show turning resistance when you go beyond 3 (at room ~20oC). Having said that, TRVs are crude devices, so some might not be that accurate and could start shutting off the flow at '4' so could make it heat slower than if at '5'. At '4', it might be beginning to shut the valve off.

The exact same thing applies to most room 'stats - the room won't warm up faster if you ask for 30oC instead of 22oC; it'll just run the boiler and supply heat until the desired temp is reached.  (Some exceptions, some 'smart' controllers note when they are getting close to the asked-for temp, so will start to ease off power.)

As regards removing the TRV head, as soon as you do this the valve is fully open, and remains so. If you remove the head, you'll find a metal 'pin' coming up out of the valve body - this is what's pushed down by the TRV head as the room heats up. If you push down hard on that pin, it should go in to the body against spring resistance, and pop out instantly when released.

And the reason why you do not have a TRV valve on the rad where the room stat is located, is because the two temp control systems - the TRV and the room stat - could easily end up fighting each other. Eg, if you set your room stat at 21oC and the TRV at '3', then your room will never reach 21oC and the boiler will keep trying to run. Why? Because the TRV will have shut off that rad at around 20oC...

Anyhoo, you want neat rad valves on your column rads? In that case fit two manual valves - call one of them 'lockshield' and the other 'control', but it doesn't matter as they will both stay at whatever setting you place them. And that setting should allow your sitting room to heat up at a decent speed, whilst also allowing all the other rooms in the house to do so too.

If you had a super-powerful rad in the sitting room, and its valves open too far, that room would warm up very quickly. But then it would shut off the boiler via the room stat, so the rest of the house wouldn't have had a chance to get up to temp. So, you'd tweak down the lockshield a bit to slow down how quickly that rad heats up/ limit its heat output. That then gives the rest of the room the same time to get to temp. 

Bendy_House

If you are planning to tweak any lockshields, and you are doing the 'first note down how open it is' job, if you find that a lockshield is much more than - ooh - a couple? of turns open, then there's a fair chance that it just hasn't been balanced at all, but just left nicely 'open' by the plumber.

Apodemus

All good stuff from Bendy_House but I would add a caveat to

Bendy_House said:

All the rads with TRVs are capable of controlling their own heat output automatically.

Remember that the TRV responds to the temperature at the TRV, which can be different to the rest of the room. If the radiator and TRV are positioned in such a way that a cold draft keeps the TRV colder than the set temperature, then the radiator may not switch off as expected. The opposite can happen if the TRV is affected by the heat from the radiator more than the rest of the room.

sho_me_da_money

Bendy_House said:

If you are planning to tweak any lockshields, and you are doing the 'first note down how open it is' job, if you find that a lockshield is much more than - ooh - a couple? of turns open, then there's a fair chance that it just hasn't been balanced at all, but just left nicely 'open' by the plumber.

So there is a problem with knowing the original position of the lockshield side.

- The radiators in Bedroom 1, 2 and 3 were removed 6 months back and the previous rad lockshield positions were not noted
- The radiator in the living room was replaced about 2 months back and the previous rad lockshield position was not noted
- The old radiator in the hallway is the only one that I will be able to take a note of the position of before replacement.

On Thursday, an Engineer will:

- Install Bedroom 1, 2 and 3 radiators
- Replacing hallway radiator and install a new one
- Replacing existing TRV and Lockshield valves on the vertical rad with the new double lockshield valves (per notes above)

The only 2 radiators that will not be touched and/or replaced are the kitchen AND bathroom rad. These are the old style rads but I am not interested in replacing these we are focussed on renovating Living room, hallway and the three bedrooms.

How do you propose this balancing occurs given the above?

I also have some Sentinel X100 inhibitor. Would you recommend this is poured in when all rads are installed?

Apodemus

sho_me_da_money said:

Replacing existing TRV and Lockshield valves on the vertical rad with the new double lockshield valves (per notes above)

I think Bendy was suggesting two manual valves and treating one as a lockshield, rather than two lockshields. You still want to be able to control this radiator without the hassle of using a spanner on one of the lockshield valves. I guess the suggestion is that while you could fit one lockshield and one manual, it might be neater and more symmetrical to fit two manual valves.

Another_Level

Good practice to not have a trv on all the radiators, usually the hallway radiator where the roomstat has temperature control and act as an interlock.

It's been mentioned about balancing the system, its important to accurately balance the system and see how it preforms afterwards. Further water flow coaxing may be required.

Take the trv heads/sensors for balancing. Using a couple of clip on pipe thermometers makes the job so easy