Radiators Not Heating But Hot Water Works in Orpington or Bromley?
If your taps are hot but your radiators stay cold, the boiler probably isn’t “broken.” This is usually a circulation or distribution fault — and it’s one I see weekly across BR5, BR6 and Bromley.
If neither heating nor hot water is working at all, that’s a different scenario — start with no heating and no hot water help instead.
Boiler vs Heating Circuit — What’s Actually Happening
In most combi systems, hot water and heating run through different internal pathways.
If hot water works but radiators don’t, the boiler is firing — it’s just not pushing heat into the radiator circuit properly.
Most Common Causes in Local Homes
- Stuck TRVs (thermostatic radiator valves)
- Airlocks in pipework
- Sludge build-up (magnetite)
- Circulation pump issues
- Diverter valve fault in combi boilers
In older properties around Petts Wood or Shortlands, sludge is common — especially where systems haven’t been flushed in years.
Cold at the Bottom vs Cold All Over
Cold at the bottom? Usually sludge build-up restricting flow.
Completely cold? Often circulation or valve issue.
The difference matters. It changes the fix.
What Happens If You Ignore It
Running a system that can’t circulate properly puts strain on:
- The pump
- The heat exchanger
- The boiler itself
It can also lead to pressure behaviour changes. If your pressure is low too, check this: low boiler pressure explained.
When It’s Something More Serious
Occasionally, heating issues are linked to hidden leaks — especially if ceilings show staining. If that’s happening, read: ceiling leak from upstairs bathroom.
About SKR Plumbing & Heating
I’m Stuart — sole trader covering Orpington & Bromley daily. You can check independent reviews here: Checkatrade profile.
If I’m on a job, I’ll return your call as soon as I’m free.
Heating Circulation FAQ
Can I fix stuck radiator valves myself?
Sometimes gently freeing the pin works — but if unsure, it’s safer to have it checked.
Does this mean my boiler is broken?
Not usually. Hot water working suggests the boiler is firing normally.
Is sludge dangerous?
It’s not dangerous, but it reduces efficiency and can damage components over time.
How fast can you attend?
Call 07706 889 614 — I cover BR postcodes daily.
Radiators Still Cold?
If your boiler is on but heat isn’t moving, it’s usually a fixable circulation issue.
Call 24/7 – 07706 889 614