Issue with Radiator connected with 8mm Piping to existing 15mm Copper

[KNCowans]

Hello all

I have an issue with One Radiator that I hope you can offer some advise on.

I had a Type 11, 1000mm x 600mm Radiator Installed in the Living Room which had no Radiator prior, in 2018.

Even though the Radiator got Hot it never sufficiently Heated the Room.

In 2022, I had the Radiator replaced with a Type 21, however, this too is not Heating the Room sufficiently even though it should be more than capable of doing so.

All of the other Rooms get to their Set Temperatures in approximately 1 Hour, however, the Living Room struggles to get up to Temperature in 4 Hours, sometimes longer.

The Radiator was connected to the existing 15mm Copper Pipework utilising 8mm Plastic Pipes.

Could the use of the 8mm Piping into the 15mm Copper be the issue?

I have had the System Balancing checked, multiple Times and it is correct.

Thanks in advance

Kevin

 

[oldbuffer]

1. If the balancing is truly correct, and other radiators are heating in a reasonable time, I would think it unlikely that the microbore is the problem.
2. How did you size the new radiator? On-line calculator or manually. It may simply not be big enough to heat the room.
3. What size is the room? How many exterior walls? Area and type of windows?

 

[KNCowans]

Hello

Thanks for the Reply.

The Radiator was Sized by the Heating Engineer and was intentionally Oversized.

The Radiator is a Type 21 at 1000m x 600mm and Rated at 1345 Watts (1121 Watts was recommended by the Radiator Calculator)

The Room is 3.9m x 3.0m, Two Exterior Walls and New UPVC Double Glazing, approximately 2.5m2.

Thanks

Kevin

 

[Ltnman]

Search YouTube on how to balance a central heating system.

 

[cross thread]

Is the rad getting hot across its surface area ,

 

[Chivas69]

Does the rad eventually get too hot to touch?
If you turn the other rads thermostats to zero does it get hot quicker?

 

[Johntheo5]

If you have a heat gun measure the rad flow and return temps as accurately as possible, also the room temperature, its easy then to calculate the actual output of that rad.

 

[KNCowans]

Hello

Thanks for the Replies and apologies for not Replying sooner, I have been dealing with some things.

I decided to check the Balancing for myself, I have never done it before so researched it as much as I could prior to trying it.

First of all I checked to see how much the Lockshield Valves were Open.

The Five Radiators had their Lockshield Valves Open approximately ¼ of a Turn and the problem Radiator had its Lockshield Valve Open approximately 1 Full Turn, which from what I had researched seemed excessive.

I proceeded to follow the instructions Ifor Balancing the Radiators and what I ended up with was that the Lockshield Valves on the 5 Radiators were barely Open whilst the Lockshield Valve on the problem Radiator was Open approximately ⅛ of a Turn.

Currently, it seems to be working quite well, I shall see how it is in the coming Days.

Thanks

Kevin

 

[Agile]

You cannot properly balance rads without any way to measure the flow and return temperatures.

But I can because I traim myself to measure temps by touching them.

 

[KNCowans]

Hello Agile

I am aware of that hence why I purchased a Differential Thermometer.

I managed to achieve an 11⁰C Drop, give or take a Degree across each Radiator, except for the Living Room Radiator as I was unable to get a reliable Temperature Reading.

Thanks

Kevin

 

[Johntheo5]

What flow/return temps are you getting?

 

[KNCowans]

Hello

I am using Weather Compensation so the Flow and Return Temperatures fluctuate.

Thanks

Kevin

 

[Madrab]

Not having all the required information - what's above/below (heated room/air gap under floor) - ceiling height (2.4m) - floor type (suspended) - wall type (cavity) - window facing (south) - then I have added some standard defaults

Quite simply - it seems that rad is not big enough for the room.

Of course a lot of calculators can be very different but even with a just 'off the top of my head' assessment, given that room size, it would certainly need a larger rad than is installed. Given the fact that the rad is heating up but the room is still cold would seem to bear that out.

 

[Johntheo5]

Ideally, Kevin, the 11C dT should be done, IMO, with a high flow temperature, by doing this, then you will get the highest possible output with a lower flow temperature (WC) which can increase the condensing benefit considerably. If you set up a dT of 11C at 75C flow temperature, you will get the rated output of the rads and for example if the WC determined that you only need a flowtemp of 40C then the rad will emit 29/30% of its rated output, but if the 11C dT was set up with a flow temperature of say 45C then the flow temp would need to be 45C to achieve the same 29/30% output so WC curve would need to be higher, also, even though rarely required, the rated output of the rad at 75C will then only be 76% of its rated output and the dT will then be 29C which will trip a lot of gas boilers.

 

[Agile]

My simple rule of thumb of 100 W per sq meter would make that rad output about right IF the flow temperature was about 82C or at its design temperature.

So are there any undisclosed heat losses? Leaking windows? Vents to the outside?