Radiator hot at top cold at bottom. Whats wrong?
Posted 17 September 2007 - 07:58 PM
1 of my radiators is cold at the bottom, but hot at the top. Whats the likely cause and how do I fix it?
Posted 17 September 2007 - 08:22 PM
If the rad is a modern thin steel unit check for any corrosion/rust around the ends. If that's bad then consider replacing the rad. Otherwise drain system, remove rad from wall and flush out with hose in the garden. Consider doing other rads while it's drained. Refill and test, then if all ok then put the right qty of corrosion inhibitor in.
There are various chemical sludge removers and system cleaners you can try but if the system is really full of the stuff they may not work well and the dreaded "power flush" of the whole system maybe required.
Shop around for the best deal on a power flush. Some companies like British Gas have had a bad reputation for trying to charge £600 and hinting that they may refuse to cover repairs under their maintenance plan unless you agree to it. You can find it a lot cheaper if you shop around.
If you do have a BG contract then check the small print. I believe they charge for the first power flush after you sigh up but subsequent ones are free.
Posted 17 September 2007 - 08:41 PM
Posted 18 September 2007 - 06:43 AM
Posted 18 September 2007 - 08:11 AM
It was just a thought... and worth checking before British Gas try and sell you a "gas softener" or something!!!
Posted 18 September 2007 - 09:28 AM
Posted 18 September 2007 - 10:08 AM
Posted 20 September 2007 - 08:21 AM
I've got a similar problem. The pipe up to the rad valve (TRV) is very hot, but the rad only gets luke warm. Will I need to replace the TRV or is there a way of adjusting them internally? The valve itself is only a few years old.
Posted 27 September 2007 - 12:58 PM
Sorry I didn't get back quicker. I wanted to be sure it was cured, then I got distracted!
When BG came the guy said the system had air-locked. He turned all the other TRV's to off and the cold rad one to max, turned the master stat up for 10 mins and let it run. This has cured it!
Posted 01 October 2007 - 11:14 AM
Posted 19 October 2007 - 10:16 PM
I've tried bleeding them, but that doesn't help.
I then closed all the TRV's when the heating was on and opened the radiators one by one, from the bottom of the house - this seemed to help a few of the radiators, but still the problem persists on the others.
I did notice that one radiator is hot at top and hot at the bottom - near the TRV, but hardly even warm at the bottom on the other end.
Can anyone please help?
Posted 20 October 2007 - 06:55 AM
However if you read the above postings first, you will know it could alternatively be black sludge. Do you know for sure that inhibitor was put into the system 12 months ago on commissioning? Did this problem occur last winter?
Posted 21 October 2007 - 11:35 PM
I think the radiators were hot (top and bottom) last winter, but can't be 100% sure. we have however had 2 extra small radiators added since then, so the system was drained etc.
I doubt inhibitor was added to the system on comissioning, should it have been? Could lots of radiators be full of sludge already?
Posted 22 October 2007 - 07:02 AM
Posted 22 October 2007 - 09:27 AM
jos... I think its you, i notice also have posted about problems with your megaflow not heating up also
this must be linked with the rads not getting hot also.
are you sure that its all plumbed in correctly
you have added 2 radiators onto the system, where did you connect onto the system?
is your system a Y plan or S plan.
Y plan is a 3 port motorised valve.
S plan is min 2 x 2 port motorised valves or more.
Is the boiler temp low, med, high?
And do you have an AUTOMATIC BYPASS VALVE. check if you do have a bypass that its not open too much that it lets the heat go straight back to the boiler. IM THINKING THIS COULD BE THE PROBLEM.
You say the rads are weak, and the megaflow is also, but the pipes going into and comming out the megaflow are hot.
boiler pump, or bypass,
Posted 25 October 2007 - 11:34 AM
If the system wasn't properly flushed on install, and no inhibitor added on install or after the 2 radiators were added in the summer - then I assume this could be partly the cause of the issue?
Also one radiator (top of system) is always needing to be bled - every week.
I appreciate your help!
Posted 25 October 2007 - 01:25 PM