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Jul 19, 2012
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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!!

Cheers

Suds
 
yes it's possible there is an air lock. in the first instance I would turn off the rad that is working to see if the other one gets any heat. if it does it will be a case of balancing the two ads so they both heat up.
 
yes it's possible there is an air lock. in the first instance I would turn off the rad that is working to see if the other one gets any heat. if it does it will be a case of balancing the two ads so they both heat up.

Thanks for the reply,

I've tried balancing by turning down/ off all other reads in the house and the hot water still didn't want to travel to the towel warmer... Probable air lock yes?
 
Turn off all rads except towel rail, then with heating on, open vent in towel rail and drain off 2 litres of water. Be prepared to increase pressure at boiler and also check valves are bi-directional.
 
Leading on from above, have you put straight thermostatic valves on the towel rail? If so check the direction they are going as they usually only go one direction.
 

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