Radiators dont heat up very well

A question about : Radiators dont heat up very well

Hi, We have a Worcester Bosch condensing boiler which is about 2years old now. However although we get hot water from it our radiators barely get warm. The radiators are the original ones from when the house was built which is about 30 years ago. Do we need to replace them or do they just need flushing out or whatever is done. Its not the fact they might need bleeding cos thats been done. Thank you

Best answers:

• There are all sorts of reasons why this could be happening. What is your boiler model/type? Do the rads "barely get warm" at the top or at the bottom? Does the pipework get hot and the radiators not? You may have a faulty three port (Y plan) or zone valve (S plan) or internal divertor valve if you have a combi. You may have crud in the rads. You may have a pipework blockage preventing circulation and if its an older system still using an F&E tank in the roofspace the pipework associated with that would be the first place I'd be looking for a blockage.
  TBH you really need to get someone in to look at it but in the meantime if you can provide some further detail about your system we may be able to narrow it down a bit for you.
  Cheers
• To me it sounds as thought the system needs bleeding and refilling. Do the radiators feel warm at the top, but cooler near the bottom? This means the radiators need bleeding. If this is a closed system, there will be a pressure dial somewhere near your boiler and I think the website for Worcester Bosch has detailed instructions on how to fill and pressurise your system. You need to do this about every 6 months
• Could you say a little more about your system? Boiler type/model? Tanks in roof with standard HW cylinder in airing cupboard? Any motorised valves? No tanks in roof but unvented cylinder? No cylinder at all? etc etc etc. Thanks
  Cheers
• Putting a new boiler on with old rads can cause problems eventually as crud/rust from the old rads/pipes can clog the boiler. You may need this checking and flushing and a rust inhibitor added. How is you water pressure assume you've got good pressure at the guage 1.5 - 2 bar.
• How warm is the house? I can't imagine needing the radiators hot at this time of year to be comfortable. Maybe the room thermostat has decided the room is warm enough and switched the radiators off. Also, if the house is nearly warm enough, it should only make the radiators warm, not hot.
• Thank you for all replies. Do any of you know approximatly how much it would cost for them to be chemically flushed before we go down the road of having new radiators.
• Isn't a WB Greenstar covered by a 2 year warranty (as long as the 1st year annual service has been carried out by an WB approved RGI)? If so isn't it worth getting WB out on a warranty repair basis to establish if there is a fault on the boiler itself?
  Assuming that the install was properly done and registered and that it's not yet gone out of warranty of course.