DIY Doctor UK DIY Forums

Hi there, hope you can help me, we've been going round in circles for weeks, and shelled out money to plumbers who have replaced parts, serviced boilers, and its getting worse rather than better!

Our radiators are luke warm or cold, but the water to the pump, and hot water tank are boiling. The hot water is ok, and heats up, and we've had the valve that switches between the hot water and the central heating replaced. The boiler clicks on but not for long enough to raise the temperature in the house above 17C. I've felt the water in the pipe feeding from the boiler and thats boiling, so I reckon the water isn't moving away from the boiler, and thats why it doesn't stay on for very long, and doesn't always click on, when the thermostat clicks past the present temperature. The pump is noisier, but our plumber (!) said it was working. We have bled the system of air. We have put 'de-sludger' through the system (4weeks) and flushed it. We have had no joy with that so have de-sludged again and washed out couple of downstairs rads.

Please help - my fingers are freezing typing this! I'm going into a room with a bit of heat now.... the kitchen!

Yours hopefully......

i know your plumber said the pump is ok but it does sound like the pump. your boiler isnt stayin on long because it cant get rid of the heat so it just shuts down on overheat

[quote="keitht"]i know your plumber said the pump is ok but it does sound like the pump. your boiler isnt stayin on long because it cant get rid of the heat so it just shuts down on overheat[/quote]

hi, i have the same type of promlem here, the thing is that it is the last radiator on the line, downstairs have changed valves, flushed through rads and even the pipe work, but the prob is still there, rad did get hotter after this fix, but still not as hot as the rest of the rads, could this also but pump related, appreciate your advice.

i had a problem similar tothis a few years ago and the spindle on the pump had sheared off. even though the pump was indeed working , the impeller that pushes the water around the house wasnt spinning at all hence no heating. a new pump only costs about £60. good luck.

I THINK THE IMPELLER ON THE PUMP HAS SHEARED OFF THE ROTOR OF THE MOTOR. THE HOT WATER ISN'T BEING DRAWN AWAY FROM THE BOILER HENCE THE REASON IT IS SHUTTING OFF.

TO CONFIRM THIS- REMOVE THE CENTRE BLEED SCREW ON THE PUMP WHILE IT IS RUNNING. INSERT A SCREW DRIVER AND YOU SHOULD FEEL OR HEAR IF THE IMPELLER IS ROTATING.

GOOD LUCK!!! :wink:

zac try turning off a cuple of the rads that get warm like the one in the room above and room next to and see if it gets warm your system may just require balancing. iif it gets warm gradually turn the ones u turned off back on. or if you av thermostatic rad valve on it, it maybe faulty

Thanks everyone for your comments so far. We had a central heating guy come and have a look at it yesterday. He says we have got a blockage in a pipe near the hot water cylinder (and pump). He is going to power flush it after doing some pipe work, and is going to put a filter on the system to help prevent the problem re-occuring. Since we flushed out the radiators downstairs, we have got some heat upstairs (so probably needs balancing), but not enough BUT the pump is quieter?!. Downstairs is freezing - especially in this weather (ice everywhere outside!). The guys coming to do the work on Wednesday, so I'll keep you posted. I will question whether it could be something broken in the pump tho'. Until then, I'll be in the kitchen, or curled up next to the fan heater!!!!

Thanks again everyone for your input!

Just posted a similar problem myself. would appreciate an update once you have it solved :)

geordie geoff here, i had the same problem as this, one rad downstairs not heating, took rad off flushed it through, flushed the pipework till clear water came through (didn't take long either), re-assembled, to no avail, rad still not working properly, phoned a family friend, who incidently is a pluming & heating engineer, he advised me to [u]balence[/u] the system which i did, starting at the farthest rad ie (last one on line) & working towards the boiler. This has worked fine for me, all rads working correctly now. Hope this may be of assistance for you, and save you a probable large outlay of cash. Good Luck...