Currently reading:
Rate of heating in a living room?
Discuss Rate of heating in a living room? in the USA Plumbers Advice area at PlumbersForums.net
Normally, you will get/buy a pair of radiator vaves, one will have a plastic wheel head with which you can open and shut as required, the other (return end, recommende) will also have a plastic wheel head but this is only a cover and turning it has no effect, you just pull this up and open and shut this valve with a adjustable spanner, if your system is balanced then this valve will be set to 1/16,1/4,/1/2, or whatever open and don't touch this again, hence the lockshield name, you just the replace the plastic cap and if you wish to shut off the rad you just shut the the other one, when its reopened then the rad is still balanced.
You said
"At the larger value side (thermostatic) I measured a temperature of 54.2 C and at the smaller value side a temperature of 56.7 C. There were sometimes variations, but generally it's about 2.5 C colder on the thermostatic valve side "
This means to me that you have a thermostatic radiator valve (TRV) installed on the return and a wheelhead valve at the flow end, normally, it is recommended that the TRV is fitted on the flow side and the wheelhead on the return, they can be installed as yours appear to be but then the TRV must be of the bi directional type, ie, two arrows on the valve body, some installers here say that even if bi directional that they should always be installed on the flow side, mine are all on the return.
Can you post a pic of both to make sure we are talking about the same thing?
You said
"At the larger value side (thermostatic) I measured a temperature of 54.2 C and at the smaller value side a temperature of 56.7 C. There were sometimes variations, but generally it's about 2.5 C colder on the thermostatic valve side "
This means to me that you have a thermostatic radiator valve (TRV) installed on the return and a wheelhead valve at the flow end, normally, it is recommended that the TRV is fitted on the flow side and the wheelhead on the return, they can be installed as yours appear to be but then the TRV must be of the bi directional type, ie, two arrows on the valve body, some installers here say that even if bi directional that they should always be installed on the flow side, mine are all on the return.
Can you post a pic of both to make sure we are talking about the same thing?
068 Traditional TRV Angled Brushed (Satin) Nickel Thermostatic Radiator Valves - Column Radiators 4u
Radiator Valves 4u, Radiator Valve > Thermostatic > Traditional, Brushed (Satin) Nickel, Height: 133mm, Width: 87mm, Depth: 55mm
www.columnradiators4u.co.uk
The link above shows the valves which I have installed.
I've had a look and I do not see any arrow(s) indicating any direction. I re-took the time for how long it takes the rad to get to maximum temperature when the heating is already fired up, and it takes up to 20 minutes for the radiator to reach maximum temperature.
I re-took the temperature at the valve ends and I get:
53 C at the TRV end, and 57.10 C at the lock-shield valve.
So:
a) I'm consistently getting a higher temperature at the lockshield end
b) the retailer states that they "always recommend installing the wheel head on the flow in and the lock-shield on the return"
c) I do not see any directional arrows
d) the rad itself can have the flow/return attached to either side
So perhaps it could be concluded that the valves are not bi-directional, and that the flow/return pipes have been attached to the wrong valves?
Your pipework is OK as the rad has no special instructions, the TRV and the Lockshield should be swapped, ie the TRV on the flow & lockshield on return but what actual difference this makes to the flow I've no idea, perhaps none. I've never seen that type of TRV and looking at its spec it doesn't say Bi directional but I would suspect not.
Heat up time of 20 minutes seems very long but again if these are cast iron maybe normal, I'm sure some one on here can advise, the measured flow/return temps of 57.1C/53C, with a deltaT of 4.1C even though still low IMO are possible but if its not normal for the rads to take this 20 minutes heat up time then the hot water may be partly short circuiting and not giving you the output of a 35 deg rad, ie 5177 BTU or 1.52kw.
Practically speaking my only suggestion is to get hold of a oil filled rad or equivalent, turn off the rad, set the electric heater to whatever power settings are available and that should point you in the right direction. My oil filled rad has three settings, 0.8kw(2730BTU), 1.2kw(4094BTU) and 2kw(6824BTU)
Heat up time of 20 minutes seems very long but again if these are cast iron maybe normal, I'm sure some one on here can advise, the measured flow/return temps of 57.1C/53C, with a deltaT of 4.1C even though still low IMO are possible but if its not normal for the rads to take this 20 minutes heat up time then the hot water may be partly short circuiting and not giving you the output of a 35 deg rad, ie 5177 BTU or 1.52kw.
Practically speaking my only suggestion is to get hold of a oil filled rad or equivalent, turn off the rad, set the electric heater to whatever power settings are available and that should point you in the right direction. My oil filled rad has three settings, 0.8kw(2730BTU), 1.2kw(4094BTU) and 2kw(6824BTU)
It's a steel radiator, just in the style of a traditional column rad.
Do you mean an electric oil-filled rad which has an electrical plug which is plugged into the electrical socket on the wall and is unconnected to the central heating system?
Okay; thanks very much.
[automerge]1607356724[/automerge]
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
Last edited:
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.
[automerge]1607373674[/automerge]
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.
[automerge]1607373674[/automerge]
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.
Last edited:
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.
- Messages
- 298
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?
- Messages
- 298
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.
[automerge]1607464690[/automerge]
Perhaps return temp too high so boiler modulating down?
Last edited:
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
[automerge]1607464889[/automerge]
I shall look at that.
- Messages
- 2,558
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."
Last edited:
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.
- Messages
- 298
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.
Last edited:
- Messages
- 298
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.
Reply to Rate of heating in a living room? in the USA Plumbers Advice area at PlumbersForums.net
Similar plumbing topics
- Question
- ShowerSmellProblems
- Plumbing Jobs | The Job-board