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New Towel Rail in Loft Extension but it Won't Heat up

Postby Sudders » Mon Feb 13, 2017 10:30 am

Hi all, wonder if I can pick your brains for a minute please....

I've recently installed a new radiator and towel rail in an old loft extension with no previous heating but I can't for the life of me get the towel rail tho heat up.

I've Tee'd off from the 1st floors (floor below) flow and return and using 15mm speedfit pipe came up into the right side of the eaves in the loft. From there I used an elbow joint then continued the run for about 5 meters where it comes through the plasterboard to the position of the new full radiator.

Here I T'd the flow into the rad then kept the run going into the left side of the eaves and then along for 5 more meters till it joins into the back of the towel rails copper pipe via another elbow. The return pipe has the same run except teeing into the other side of the rad.

The new rad gets lovely and toasty but my problem is that the towel rail doesn't. Infact, most of the flow pipe after the new rad' s T doesn't.

I've bled all Rads and checked the system pressure and there doesn't seem a problem there, although, before refilling the system I added cleaner to the towel rail so am not entirely sure if it's cleaner fluid or system water I'm bleeding...

My thoughts....

1 - not enough pumping pressure to get to the end of the run?

- but the boiler is a 24 kW with only 8 previous Rads installed and the new rad gets very hot.

2 - a problem with the new towel rail valves somehow blocking circulation of the water?

- I cracked the valve nut on the flow side and after a minute the water started to get hot. This was the only time that section of pipe had got hot.
- if the valves were dodgy would the rest of the heating circuit work?

3 - the pipe run in the left side of the eaves takes a sort of 'rainbow' shape as it goes over the entrance hatch in the wall and is therefore higher than the towel rails valves.

- could this section of pipe have an airlock stopping the circulation of water?

Sorry this is quite long but wanted to give as much info as possible.

Any advice and help would be gratefully received!!


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Postby Anto255 » Fri Feb 17, 2017 4:51 pm

Of ur heating system is an open system then it won't be strong enough to heat up rad in attic.
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Postby stoneyboy » Wed Feb 22, 2017 7:53 pm

Hi Sudders,
Suggest you turn off all radiators except the towel rail and see if it then gets hot, don't forget to bleed the towel rail as you do this.
If it does get hot you will need to balance the system, if it does not try fitting a bleed valve in the top of your rainbow loop.
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