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

sho_me_da_money

Jeepers_Creepers said:

fezster said:

I've decided to place the thermostat in the living room and install the Netatmo Smart Radiator TRVs everywhere else. Why? Because the living room is one of those vertical Anthracite models that would look HORRIBLE with white Netatmo TRV.

All other Radiators in the house are white and look aesthically better with the smart TRV.

Just remember that this radiator (without a TRV) will then always heat up regardless of which other radiator is calling for heat. This would probably mean this room will overheat.

Ooooh - a good point!
Yes, when any of these other TRVs 'call for heat', the boiler will come on and the pump run. Hot CH water will go in to any other rad with an 'open' control valve. The room stat in the sitting room will have no bearing on this.
Hard to think of an easy way to sort this, but a zone valve fitted to the supply pipe to that rad would do it, controlled by a remote wall stat just for that room. Would access to this pipe be possible?

Interesting one here specifically on this point.

- So i had all my three smart TRVs set to hit desired temp (20 degs) from 06:00
- All rads are were configured to warm from a starting temp 18 or 16.5 degrees
- The only rad that doesnt have a SMART TRV is the vertical one in the living room. It does however have a standard TRV installed on it, which is set to between 3 and 4, which is fine to get to 20 degs.
- The wireless thermostat is also in the living room and set to 20 degs. Its placed in the central area of the room.
- All smart TRV enabled rads warmed up to desired temp pretty quickly

- Living room radiator at 09:00 (3 hours later) is still chugging away and wireless thermostat detects the room temp is about 18.7 degrees. Damn.

I then turned up the living room NON-SMART TRV to setting 5 (from setting 3.5) and the room starts heating up faster. Wireless Thermostat hits 20 degs and boilers turns off.

Now the thing I dont get, the setting between 3.5 and 4 is fine to hit 20 degs. Why the hell does it take me turning it up to 5 make the room warm up faster? I was under the impression that turning that setting lets more water to hit a higher temp like 25+ degs but why does that speed up the room warming to 20 degs? Shouldn't the flow of water to the rad on setting 3.5-4 be the same?

Sorry for the dense question....

fezster

sho_me_da_money said:

Interesting one here specifically on this point.

- So i had all my three smart TRVs set to hit desired temp (20 degs) from 06:00
- All rads are were configured to warm from a starting temp 18 or 16.5 degrees
- The only rad that doesnt have a SMART TRV is the vertical one in the living room. It does however have a standard TRV installed on it, which is set to between 3 and 4, which is fine to get to 20 degs.
- The wireless thermostat is also in the living room and set to 20 degs. Its placed in the central area of the room.
- All smart TRV enabled rads warmed up to desired temp pretty quickly

- Living room radiator at 09:00 (3 hours later) is still chugging away and wireless thermostat detects the room temp is about 18.7 degrees. Damn.

I then turned up the living room NON-SMART TRV to setting 5 (from setting 3.5) and the room starts heating up faster. Wireless Thermostat hits 20 degs and boilers turns off.

Now the thing I dont get, the setting between 3.5 and 4 is fine to hit 20 degs. Why the hell does it take me turning it up to 5 make the room warm up faster? I was under the impression that turning that setting lets more water to hit a higher temp like 25+ degs but why does that speed up the room warming to 20 degs? Shouldn't the flow of water to the rad on setting 3.5-4 be the same?

Sorry for the dense question....

Normal TRV's use a wax capsule to measure the temperature - it is very slow in reacting and can take 1-2 hours to adjust to the ambient temperature.

You should never have a thermostat in the same room as a TRV because you've effectively got 2 temperature measuring devices fighting against one another - just as you've experienced. The best thing to do (apart from fitting a Smart TRV to this rad) is to remove that thermostat from the wall and rely on other Smart TRV's calling for heat to heat up the living room.

sho_me_da_money

fezster said:

sho_me_da_money said:

Interesting one here specifically on this point.

- So i had all my three smart TRVs set to hit desired temp (20 degs) from 06:00
- All rads are were configured to warm from a starting temp 18 or 16.5 degrees
- The only rad that doesnt have a SMART TRV is the vertical one in the living room. It does however have a standard TRV installed on it, which is set to between 3 and 4, which is fine to get to 20 degs.
- The wireless thermostat is also in the living room and set to 20 degs. Its placed in the central area of the room.
- All smart TRV enabled rads warmed up to desired temp pretty quickly

- Living room radiator at 09:00 (3 hours later) is still chugging away and wireless thermostat detects the room temp is about 18.7 degrees. Damn.

I then turned up the living room NON-SMART TRV to setting 5 (from setting 3.5) and the room starts heating up faster. Wireless Thermostat hits 20 degs and boilers turns off.

Now the thing I dont get, the setting between 3.5 and 4 is fine to hit 20 degs. Why the hell does it take me turning it up to 5 make the room warm up faster? I was under the impression that turning that setting lets more water to hit a higher temp like 25+ degs but why does that speed up the room warming to 20 degs? Shouldn't the flow of water to the rad on setting 3.5-4 be the same?

Sorry for the dense question....

Normal TRV's use a wax capsule to measure the temperature - it is very slow in reacting and can take 1-2 hours to adjust to the ambient temperature.

You should never have a thermostat in the same room as a TRV because you've effectively got 2 temperature measuring devices fighting against one another - just as you've experienced. The best thing to do (apart from fitting a Smart TRV to this rad) is to remove that thermostat from the wall and rely on other Smart TRV's calling for heat to heat up the living room.

Hi mate,

I get the conflict part and that makes sense. Sorry if I misunderstood but what do you mean when you say "is to remove that thermostat from the wall and rely on other Smart TRV's calling for heat to heat up the living room"

Would a way to combat that problem be to remove the normal TRV from the living room rad, install a standard valve, leave it in the fully open position, leave the wireless thermostat in the living room with a temp set to 20 degs?

That would allow the wireless thermostat to be the authoritative device for temp in the living room without any competition AND being more accurate and faster reacting than a wax based TRV.

FreeBear

If the TRV valve and head are from different manufacturers, I'd suggest taking a look at the pin height. If the head is designed to work with a valve body with a short pin and you have one with a long pin, then it is quite likely water flow is being restricted and shut off too early. This is one reason smart TRV heads are usually supplied with an assortment of collars & spacers.

Rather than replacing the TRV (head & valve) with a conventional valve, you could just take the head off. It is only secured by a knurled ring..

sho_me_da_money

FreeBear said:

If the TRV valve and head are from different manufacturers, I'd suggest taking a look at the pin height. If the head is designed to work with a valve body with a short pin and you have one with a long pin, then it is quite likely water flow is being restricted and shut off too early. This is one reason smart TRV heads are usually supplied with an assortment of collars & spacers.

Rather than replacing the TRV (head & valve) with a conventional valve, you could just take the head off. It is only secured by a knurled ring..

Brilliant point actually. Just twist to the highest setting and screw off the TRV. I like that.

Saves me money plus i already have anthracite metal paint.

Jeepers_Creepers

sho_me_da_money said:

Jeepers_Creepers said:

Interesting one here specifically on this point.

- So i had all my three smart TRVs set to hit desired temp (20 degs) from 06:00
- All rads are were configured to warm from a starting temp 18 or 16.5 degrees
- The only rad that doesnt have a SMART TRV is the vertical one in the living room. It does however have a standard TRV installed on it, which is set to between 3 and 4, which is fine to get to 20 degs.
- The wireless thermostat is also in the living room and set to 20 degs. Its placed in the central area of the room.
- All smart TRV enabled rads warmed up to desired temp pretty quickly

- Living room radiator at 09:00 (3 hours later) is still chugging away and wireless thermostat detects the room temp is about 18.7 degrees. Damn.

I then turned up the living room NON-SMART TRV to setting 5 (from setting 3.5) and the room starts heating up faster. Wireless Thermostat hits 20 degs and boilers turns off.

Now the thing I dont get, the setting between 3.5 and 4 is fine to hit 20 degs. Why the hell does it take me turning it up to 5 make the room warm up faster? I was under the impression that turning that setting lets more water to hit a higher temp like 25+ degs but why does that speed up the room warming to 20 degs? Shouldn't the flow of water to the rad on setting 3.5-4 be the same?

Sorry for the dense question....

As Fezster says, wax TRVs are crude devices. You could set all your TRVs to '3', but I wouldn't be too surprised if this returned a 2 degree room temp variation between them. 
Almost certainly your sitting room TRV - set between 3 and 4 - was in a partially-off situation, so was reducing the output of the rad, to an increasing degree as the room warmed up. Ie, it prevented the room from properly heating up.

Jeepers_Creepers

sho_me_da_money said:

Would a way to combat that problem be to remove the normal TRV from the living room rad, install a standard valve, leave it in the fully open position, leave the wireless thermostat in the living room with a temp set to 20 degs?

That would allow the wireless thermostat to be the authoritative device for temp in the living room without any competition AND being more accurate and faster reacting than a wax based TRV.

That's the best solution given your current setup. Ie, the 'smart' TRVs sort out their associated rooms - that's all good - and the sitting room is then controlled by the wireless stat.

The only issue is, whenever any of the 'smart' TRVs call for heat, your sitting room rad (and any other remaining 'manual' rads) will also come on, and the room stat won't do anything about this.

Say your sitting room is nicely warm at 21oC, which is what the room stat in there was set to - so it's now switched off. All good. Then the smart TRV in a chilly bedroom tells that bedroom rad to come on - your sitting room rad will also come on for the same duration. Your sitting room could become 22, 23, 24oC...