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Bathroom rad on gravity feed

Postby lee_007 » Thu Oct 04, 2007 9:21 pm

My bathroom radiator is only getting warm. I recently changed it for a heated towell rail when I refurbished my bathroom, but there was no change. It is seperate from the rest of the radiators which are pumped and is tied into the hot water cylinder loop. The inlet goes into the loft and is tied into the vent c/h and the return is tied to the return close to the boiler. I am getting water flow on both pipes, albeit the supply side only half the flow of the return. The inlet is scorching hot, but only getting a warm radiator at best. All connections are at the bottom of the rad, with the inlet slightly lower than the return which I suspect as part of the problem. I'm ok with most plumbing, but this one has me scratching my head somewhat. Anyone here who can tell me the fundamentals of gravity fed rads and how they should work? Any info would be greatly appreciated. Regs, Lee
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Simply Build It

Postby htg engineer » Fri Oct 05, 2007 12:38 pm

They will only get warm, to get the radiator hot, you will have to re-pipe it into the heating flow and return.

Never seen a or heard of a radiator piped into the primaries of a gravity hot water system.

I wouldn't recommend it and I definately wouldn't plumb one in like that.
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Postby lee_007 » Fri Oct 05, 2007 10:21 pm

Thanks for the advice htg engineer, seems the pipework in the loft was full of obstructions, so where the vent teed off into the supply for the rad I replaced the tee and elbow which where gunked up, and my radiator is nice and toasty again. I reckon there is a little more gunk in the pipework in the airing cupboard and will have a bash at that next week.

I have seen the exact same blockage problem in several pumped C/H systems before, where I changed a rad in a bathroom and could not get enough water back into the system and hence warm or cold radiators in the house.

Gravity fed bathroom radiators are not unheard of, I came across several during my bathroom installation days and some of my mates still in the biz come across them too. Its nice to have a warm bathroom when you do not want to heat the rest of the house. although you could use an electric immersion heating element in the radiator with a timer, or go completely electric altogether... The latter employing an electrician and putting heating engineers and plumbers out of work!

Anyway, all's well that ends well.


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