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View the thread, titled "Rate of heating in a living room?" which is posted in UK Plumbers Forums on UK Plumbers Forums.
Okay; thanks very much.
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I might just get a convection heater, as opposed to an oil-filled one, as they appear to be cheaper. That is, unless there's any reason why not.
This one has the three settings of 0.75, 1.25 and 2.0 kW.
Stylec Electric Convector Heater in White - 2000W
Find Stylec Electric Convector Heater in White - 2000W at Homebase.
www.homebase.co.uk
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That should do the job and you can't go wrong for £20.
For interest, I have one of my rads (1.6kw) shut off for the past hour or so, when fully cool I will time it to reach full temperature again.
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With a room temperature of 20.3C and "cold" rad at 22C, it took 12 minutes to fully heat up. I would imagine that if the room was cold that the rad would take a few minutes more so ~ 15/17 minutes so perhaps your rad heating time isn't that outrageous.
My rad is a K2.
For interest, I have one of my rads (1.6kw) shut off for the past hour or so, when fully cool I will time it to reach full temperature again.
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With a room temperature of 20.3C and "cold" rad at 22C, it took 12 minutes to fully heat up. I would imagine that if the room was cold that the rad would take a few minutes more so ~ 15/17 minutes so perhaps your rad heating time isn't that outrageous.
My rad is a K2.
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So, I've used a 2 kW heater without the fan on so as to make it as similar to the radiator as possible. I placed it at the same room location as the rad.
I've had the heating off in that room so the unheated room had a temperature of 11 C. It took 2.5 hours to get the room temperature up to 20 C.
The heater cut out at 20 C, so presumably the thermostat cut in. I turned the heater off at this point so that I could determine how quickly the room temperature then dropped. It dropped from 20 C to 15 C in 1 hour.
I've had the heating off in that room so the unheated room had a temperature of 11 C. It took 2.5 hours to get the room temperature up to 20 C.
The heater cut out at 20 C, so presumably the thermostat cut in. I turned the heater off at this point so that I could determine how quickly the room temperature then dropped. It dropped from 20 C to 15 C in 1 hour.
With a high flow through it and a high return temp, this radiator will increase return temperature at the boiler substantially. What is the return pipe temperature at the boiler? If your whole system was balanced so each radiator had a 15deg drop you might surprisingly be able to increase boiler flow temp yet lower return temp so increasing overall efficiency.
I am a bit surprised that with one external wall that is insulated this room temp drops to 11 deg overnight. Is the whole house cold? Are the properties next door empty? Sort that window!
I am a bit surprised that with one external wall that is insulated this room temp drops to 11 deg overnight. Is the whole house cold? Are the properties next door empty? Sort that window!
Increase your boiler set point to 75C, this should give you a 2.4 kw rad based on the 50 deg rating, if its "only" producing" 2.0 kw it should still heat up your room in 2.5 hrs. Once you have a rough idea of what these column rads are actually producing then combined with the window mod as suggested, may mean that you can retain this rad with a boiler temp of 60/65C.
I know there are several pipes connected to the underside of the gas boiler. I could easily take the temperature with the contactless thermometer, however I wouldn't know which is the return pipe, or how this could be determined.
I'll look into that then.
There are people in the properties next door. I think one particular issue with this room, is that I have removed all the paint from the timber window frame in order to re-paint. It was previously painted closed over decades and this may have helped keep cold air out!
I have done this and set the boiler temperature to 75 C for the heating system. Starting with a room temperature of 12 C, it took 4.5 hours to get up to 21 C.
When I did this for the 2.4 kW heater yesterday the room temp started at 11 C and took 2.5 hours.
Well, if a 2 kw electric heater got the temp up in 2.5 hours and a "2.4" kw column rad takes 4.5 hours then its pretty obvious that its not producing 2.4 kw for whatever reason, maybe original spec very optimistic as someone stated so what options now?
The hottest pipe is the flow probably 22mm copper. Next hottest is the return. Often at opposite ends of the boiler. Measure after boiler on for 30 min or so.
The problem is your window, that's all.
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Perhaps return temp too high so boiler modulating down?
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I could look into the temperature drop issue referred to by gpbeck above. Though even if this is sorted, perhaps it won't make the major improvement which would be required.
It's possible to get a similar style of rad and similar size, but a different brand. This may be an option.
Athens Dove Grey Triple Column Vertical Traditional Radiator 1800x470mm | Bathroom Mountain
Designer bathrooms at everyday low prices
bathroommountain.co.uk
1800H x 490W 3 Column Vertical Raw Metal Lacquered Radiator - Mr Central Heating
Find out more about the 1800H x 490W 3 Column Vertical Raw Metal Lacquered Radiator at Mr Central Heating
www.mrcentralheating.co.uk
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I shall look at that.
Modern condensing boilers are looking for a DT of 20°c as stated above. You ramp up that flow to 75 on a system balanced to a DT of 15 then as gpbeck says the boiler is most likely going to modulate down. An imbalanced system doesn't affect efficiency but will affect burner output and this might not be helping.
As John.g says if the electric rad brings the room up to temperature quicker this suggest the problem lies with the CH radiator. The heat loss for a room, or building for that matter is the same regardless of the type of energy input.
I suggest rebalancing the system to start with to see if that changes anything. If at DT 20 and still the radiator proves problematic then I would suspect it is the problem.
As John.g says if the electric rad brings the room up to temperature quicker this suggest the problem lies with the CH radiator. The heat loss for a room, or building for that matter is the same regardless of the type of energy input.
I suggest rebalancing the system to start with to see if that changes anything. If at DT 20 and still the radiator proves problematic then I would suspect it is the problem.
True, but for a individual radiator if the deltaT was say 15C and you increased the flow through it to give a reduce deltaT of 4 or 5c then the radiator output has to increase as you are raising its mean temperature.
The rad in question doesn't specify any particular side for flow/return but most of these do say that the flow should be installed on the same side as the blank vent on the top including the ones with a diverter, Mossop might just check if his is this way, ie the blank vent is directly above the flow pipe, also in the picture of his rad they have two circled items in red.
This, from a different (Rad) brochure above.....
"Also due to the unique flow diverter built within all Revive column radiators the flow MUST to be on the same side as the permanent blank which is the opposite side to the air vent bleed valve."
The rad in question doesn't specify any particular side for flow/return but most of these do say that the flow should be installed on the same side as the blank vent on the top including the ones with a diverter, Mossop might just check if his is this way, ie the blank vent is directly above the flow pipe, also in the picture of his rad they have two circled items in red.
This, from a different (Rad) brochure above.....
"Also due to the unique flow diverter built within all Revive column radiators the flow MUST to be on the same side as the permanent blank which is the opposite side to the air vent bleed valve."
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A quick calc assuming a Kvs of 1 for both the TRV and the lockshield valve (and negligible pressure drop through the rad) gives a flowrate of 6.45 LPM at a 3M loss, equals 1.8 kw at a deltaT of 4C which we know just isn't true, I still think that there is a partial short circuit between the flow and return but I suppose we will never know.
As you suggested, the flow and return are at opposite ends of the boiler, and are 22 mm pipes.
I am using a Sealey contactless thermometer, so I don't know if it being contactless as opposed to being in contact is causing an issue, or if there is some other issue such as a partial shortcut as suggested by John.g above.
The boiler was running for 30 minutes before I began taking measurements, then I took temperatures on these two pipes over the space of 45 minutes. I got (in C):
21.4 - 18.0
18.3 - 13.6
15.2 - 13.8
14.8 - 17.0
14.5 - 16.5
18.6 - 15.9
15.5 - 17.2
16.4 - 18.0
15.9 - 18.2
15.4 - 17.5
15.4 - 14.9
14.3 - 16.8
The blank is on the right side of the rad directly above the lockshield which is also on the right. From what I have read earlier, the flow ideally should be connected to the TRV (especially since the TRV used here is not bi-directional), however as the lockshield valve is consistently hotter than the TRV, my suspicion is that this lockshield is connected to the flow.
Separately, I believe if someone wanted to change the drop between flow and return on the rad, there is a "pin" on the lockshield which is turned to achieve this. I've added a photo to show the valve, then with the "cap" off, then underside of the "cap". There doesn't appear to be a "pin" to turn, but perhaps it's just turned using a hex key instead?
Attachments
How many rads are on that circuit now?, if the boiler is running and even if cycling (which it shouldn't) if more than say 4 rads on then the flow temp should be at the boiler SP whatever that is now, 60C? and the return should be around 10/15C lower.
No, not at the moment, if the other rads are hot just now then they must be heated from your boiler so the boiler flow and return should be hot?, is the room stat turned up? and programmer calling for CH? otherwise you are measuring the wrong pipes, also the boiler should not be cycling with 4 rads on.
Yes, the flow/return pipes on the boiler were hot. The temperatures above are the sets of temperatures which I go on these two 22 mm pipes. It appeared that there wasn't one pipe which was consistently warmer than the other (which is strange).
I'm not sure what you mean by the room stat? Do you mean the TRV?
By "Programmer calling for CH", I expect this is "central heating", I just flicked the relevant switches on the controller to set the boiler running, and the central heating temperature increases to 60 C or so, so I presume the controller has called for the central heating.
I think you’ve missed the pipes and measured the wall behind.
When I attempted this the second time, I had the boiler on for 90 minutes in advance. I found that if I trigger the contactless thermometer about 5/6 times at the one spot, it settles more at one temperature. By doing this I was able to determine that the right hand pipe under the boiler is the flow as it was consistently hotter.
The boiler temperature for the central heating ranged between 58C - 64C.
However, there wasn't any substantial uptick in temperature readings when I took them at various intervals. For the two pipes, I got (in C):
18.3 - 19.6
17.3 - 19.0
19.5 - 22.0
17.9 - 20.9
18.9 - 22.9
16.2 - 21.4
17.6 - 20.0
18.1 - 22.2
18.0 - 21.5
16.3 - 21.6
These are two 22 mm pipes, one to the left and one to the right. There is one other central 22 mm pipe and two other 15 mm pipes to either side of this central pipe - all three of these are cold to touch.
The boiler temperature for the central heating ranged between 58C - 64C.
However, there wasn't any substantial uptick in temperature readings when I took them at various intervals. For the two pipes, I got (in C):
18.3 - 19.6
17.3 - 19.0
19.5 - 22.0
17.9 - 20.9
18.9 - 22.9
16.2 - 21.4
17.6 - 20.0
18.1 - 22.2
18.0 - 21.5
16.3 - 21.6
These are two 22 mm pipes, one to the left and one to the right. There is one other central 22 mm pipe and two other 15 mm pipes to either side of this central pipe - all three of these are cold to touch.
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Was the flow pipe too hot to touch? Should be if over 55 deg. If so your readings are wrong. If not too hot to touch then your boiler is not running.
It wasn't too hot to touch. So, there must be some boiler issue then?
It's strange though that I'm getting this temperature on the boiler flow, as when I'd measured the flow on the rad in question, I was getting 50 C or so.
Presumably the rad can't be hotter than the flow from the boiler?
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The pipes to the radiator are plastic and covered in a shroud above the floor. Maybe you're referring to the flow/return copper pipes at the boiler?
What would the tape on the copper pipes do?
The display gives an overall temperature for the heating system which when set to the recommended "e" setting where I usually have it, is usually about 60 C which it states on-screen.
I don't know if it can provide a specific temperature for the return at the boiler, it's a WB 30i, I'd have to check that.
Even if you can't take the temps you might consider watching the boiler cycling on/off with those 4 rads on and note the on and off times for say two complete cycles, then do the same with that one rad only, if you feel like it, you would have to close one valve on each side of the other 3 rads to achieve this.
I suspect that your boiler cannot deliver its minimum output (9kw?) with all that hot water returning from the living room radiator and so is constantly shutting down. Flow pipe should be too hot to touch.
Wind the living room radiator back down so outflow from it is 50 deg or so and you may be surprised.
Oh, and sort that window. Radiator will be fine.
I’m done now.
Wind the living room radiator back down so outflow from it is 50 deg or so and you may be surprised.
Oh, and sort that window. Radiator will be fine.
I’m done now.
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