I plan to add a radiator into my attic room and run it off the 1st floor central heating loop. It will be a smallish rad. Is there any reason I cannot just add it onto the end of the existing loop - My main concern is whther the addition height will cause problems.
I can't see there being a problem, if you have enough water pressure to fill your system already and your boiler output is sufficient to take another radiator (total output of rads must be less than or equal to total output of boiler) then adding an extra rad should be fine, just T in. You may need to throttle the lock shields a little to get the balance right to force the hot water up there.
Htg engineer, just out of interest why does the vent pipe need to go 18" above the F&E tank? Presumably it's to allow for expansion when the water gets hot. However, water will equalise level between the tank and the vent pipe. I would have thought the critical issue here would be to allow sufficient space in the F&E tank between the water level when cold and the overflow outlet from the tank and that, provided that the vent pipe goes over the top of the tank and it's open end is higher than the overflow, it would be OK.
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