TBOE radiators in new build incorrectly piped

[John.g]

I really don't think it makes much of a difference as after all its a pumped circulation system, its probably no worse than the conventional bottom to bottom almost universally used system which works pretty well to my mild surprise.

 

[chris watkins]

I need someone to explain why the return should be at the bottom and what difference will it make to the system.

When designing a heating system using rads a heatloss calculation is completed to determine how much heat is going to be required to keep the room at the required temperature (say 21C) when it is, say -3C outside. This is used to select a suitably radiator to do the job. As others have said the outputs the rad manufacturers state is based on being tested in a standard way (MW-air temp = 50) Here is the important thing in your case - they also connect up the rad in a certain way, typically Top & Bottom Same End (TBSE) if you change the way it is connected then you change the radiator ability to heat the room (stated output).
This is fine if you know how the rads are going to be piped up for instants in this country we mainly use Bottom Oppersite Ends (BOC) which is less efficient at proving heat from it, still that is not a problem we just make them bigger to allow for this.
TBOE connections like yours mean that the rads can be around 15% smaller than if they had been piped BOE, why?? because when they are piped with the flow (hotter lighter) water to the top connection & the return (cooler heaver) water out of the bottom you are working with gravity & not against it. God knows what effect on its output piping it up the wrong way is having on the outputs but effectively you have very much undersized rads which will not do the job they were put there to do. Very simply they are not fit for purpose as they are currently installed.
Don't take any more old crap about this from them, ask for the heatloss calculations for your property so you can see what is require & ask them once again to install them as per the designs.

 

[John.g]

Did or do they make BOC rads with a baffle plate in the bottom header to force the water upwards through "1/2" the columns and downwards through the remainder?.

 

[John.g]

Engineer came out yesterday as they had to rehang the radiator which was not hanged properly.

Also tightened the bolts which were loose to get rid of the leak in the Heat Exchange Unit.

Regards to the Delta Temperature.
The Exchanger has flow temperature set to 75 degrees. The return temperature using thermal camera is 50 degrees, I assume this is actually much more like 70 degrees as the incoming temperature was read as 53 degrees.

Anyway we still have a lot of air in the system, he said they will powerflush the system.

He is insisting it does not matter if the return is at the top.

Also stated 3 hours to increase the temperature of the room by 2 degrees is due to room size and that we are on ground floor.

After they remove the air from the system I will have to hire someone to get a report done.

I need someone to explain why the return should be at the bottom and what difference will it make to the system.

OK then I ran a 1400 x 400 mm double rad BTOE for approx 40 minutes and I can confirm that the performance is certainly affected, unfortunately I didn't have my temperature scanner but the last ~ 1/4 of the rad was much more noticeably cooler than the remainder apart from the top. I would estimate that the performance loss at ~ 20/30%, this would possibly reduce over a longer time period but to quote Chris Watkins..."they are not fit for purpose as they are currently installed."

 

[ImranF]

Thanks. You guys are brilliant offering great advice. Also you have common sense unlike the cowboys I am dealing with. As we are in our defects period I will fight to get this resolved. I will keep you guys updated but this could take some time.

I asked them how long would it take to swap the pipes and they said 2 hours. So do not understand why they simply won't just swap the feeds around.

 

[Chuck]

Regards to the Delta Temperature.
The Exchanger has flow temperature set to 75 degrees. The return temperature using thermal camera is 50 degrees, I assume this is actually much more like 70 degrees as the incoming temperature was read as 53 degrees.

Don't assume things that are central to the diagnosis of a problem.

The fact that the flow temperature was 'set to 75 degrees' does not mean the flow temperature *is* 75 degrees, particularly if your measurements say it's 53 degrees.

If you don't trust the temperature measurement, get another one made using a proper pipe thermometer. Alternatively, press your thumb onto the pipe and count in seconds how long before it's painful enough to make you pull it off. If you only get to one it's 75°C but if you get to more than ten it's 50°C.

 

[John.g]

Thanks. You guys are brilliant offering great advice. Also you have common sense unlike the cowboys I am dealing with. As we are in our defects period I will fight to get this resolved. I will keep you guys updated but this could take some time.

I asked them how long would it take to swap the pipes and they said 2 hours. So do not understand why they simply won't just swap the feeds around.

Got a few temperatures last night with "old" temp scanner but good enough I think for comparison purposes.

 

[ImranF]

I think a comparism between TBOE and BTOE would highlight what happens if you plumb it incorrectly.

 

[John.g]

Anything in the interest of science.
All temps taken after 40/45 mins, the BOE gave the fastest warm up from cold.

View attachment 37621

 

[chris watkins]

Anything in the interest of science.
All temps taken after 40/45 mins, the BOE gave the fastest warm up from cold.

View attachment 37621

View attachment 37622

I don't supposed you took the flow & return water temps of each one do you John? only what would have told us the heat out put. Interesting to see the heat distribution across them & the mean water temp 51.53 top, 60.93 middle & 59.2 bottom