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[pscocoa]

I have a room 4.8 m by 3 m by 2.3 m high with 1 bay window North Facing - double glazed.

I want to change the radiator from a horizontal to vertical but am really not sure after looking at a couple of BTU calculators on line that what I have in mind will be sufficient.

The one coming out is single panel horizontal 6ft 10ins by 1ft 6 ins and according to calcs I need for the room size about 3200 BTU rating therefore a smaller vertical rad would be ok.

http://www.radiatorshowroom.co.uk/ovale_polished_vertical.html

Am I on the right lines for the narrower style ratings do you think eg somewhere between the 295mm and 413mm widths? The range is just an example - billions to choose from but the narrower width the better

[Kevin Wood]

I think the 6'10" radiator might have had more output than that based on figures for new rads of comparable size, but depends on design I suppose. An older style rad without any fins on the back would have had considerably less output for the size. How effective was the previous rad?

Now we have TRVs, balancing radiators isn't such an issue, so you can afford to err a little, especially on the larger side, but you want it as narrow as possible.

Of course, the same heat output might feel cooler when it's vertically mounted as the heat won't fill the room as effectively, especially if the old radiator was under the window.

[Marks DTM Calib]

My experience is that the vertical rads need to be scaled to a larger size in order for them to heat the room as effectively as the horizontal variants. In fact they rarely work as well full stop, form over function.

[Marks DTM Calib]

Interestingly, I find its more essential to balance the rads with TRV's than with no TRV's

[Kevin Wood]

Interestingly, I find its more essential to balance the rads with TRV's than with no TRV's

In what respect? I was thinking a slightly oversized radiator for the room would not result in it getting too warm with a TRV.

..or are we taking about balancing flow?

[Marks DTM Calib]

Interestingly, I find its more essential to balance the rads with TRV's than with no TRV's

In what respect? I was thinking a slightly oversized radiator for the room would not result in it getting too warm with a TRV.

..or are we taking about balancing flow?

Balancing flow

What I have observed is that if you dont balance a system (e.g. with the TRV's heads removed/set to max) you can often observe one or two rooms that dont warm up as well because the main thermostat (which has to be in a non TRV controlled area) shuts the heating off before the optimum temperature is reached.

Which is no surprise as the balancing is done to give the rads fairly equal temperature differentials and hence given the rooms an even rate of warmup.

The TRV's function is simply to shut off the rad when the room is to temperature

[Kevin Wood]

Ah, OK. In that case I agree.

[pscocoa]

I think the 6'10" radiator might have had more output than that based on figures for new rads of comparable size, but depends on design I suppose. An older style rad without any fins on the back would have had considerably less output for the size. How effective was the previous rad?

Now we have TRVs, balancing radiators isn't such an issue, so you can afford to err a little, especially on the larger side, but you want it as narrow as possible.

Of course, the same heat output might feel cooler when it's vertically mounted as the heat won't fill the room as effectively, especially if the old radiator was under the window.

Thanks to all - yes Kevin this is a very old rad - no fins.

What also comes into play is that we basically have (in the past) all doors open so heat is circulating around all rooms as our house design allows full flow in a form of interconnection and I am thinking that we can get away with something smaller as we quite often turn the stat down due to heat build up.

[Taxi_Driver]

Interestingly, I find its more essential to balance the rads with TRV's than with no TRV's

In what respect? I was thinking a slightly oversized radiator for the room would not result in it getting too warm with a TRV.

..or are we taking about balancing flow?

Balancing flow

What I have observed is that if you dont balance a system (e.g. with the TRV's heads removed/set to max) you can often observe one or two rooms that dont warm up as well because the main thermostat (which has to be in a non TRV controlled area) shuts the heating off before the optimum temperature is reached.

Which is no surprise as the balancing is done to give the rads fairly equal temperature differentials and hence given the rooms an even rate of warmup.

The TRV's function is simply to shut off the rad when the room is to temperature

When i balanced my system approx 2 years ago....i found the rads upstairs got hotter than they did before. I leave the TRV's on max now(except in the 2 spare bedrooms, about 2 out of 5 on the scale) and let the room stat control the house temp. The only rad i balanced then unbalanced on purpose was the bathroom rad as before balancing used to get hot when hot water only was selected....after balancing didnt get hot with only hot water on (did with heating on) and as its a towel rail rad decided it was better to get hot with only hot water on (and its not in the primary circuit so strange why it should get hot with only hot water selected but it does!). I also turned the bypass valve off....right or wrong...but i couldnt see the point of pumping hot water around in circles going nowhere.

[martin42]

Bypass valve is needed on some combi systems,usually a 15mm ballofix valve connected between flow and return or a rad that had lockshield valves on and both opened to allow a decent flow rate,and with the non adjustable cap heads on.

[Marks DTM Calib]

You need a bypass on an s plan system so when the stat says enough heat and shuts the zone valve, the pump overrun on the boiler can continue to circulate the water.

Not needed on a y plan