UFH diagnosis
Underfloor Heating Not Warming Up — Why & How to Fix
Cold room with UFH on is almost always one of four things — and only one of them is the boiler.
When a wet UFH system doesn't warm a room, our first four checks are always the same: cover depth over pipe, insulation below the pipe, manifold balancing, and boiler flow temperature.
Get one of them wrong and no amount of running the system will fix it.
Four common failure modes
| Symptom | Likely cause |
|---|---|
| Long warm-up, then room heats | Screed too deep over pipe — needs longer runtime |
| Room never gets warm | Insufficient insulation below pipe |
| Some loops warm, others cold | Manifold not balanced or airlocked |
| System runs constantly | Boiler flow temp too low for radiator+UFH combo |
Screed depth rules
- 30mm minimum cover over pipe for Cemfloor
- 35mm minimum cover for anhydrite
- Anything less than 25mm risks pipe shadowing
- More than 75mm makes UFH sluggish and inefficient
Frequently asked
UFH not working?
Tell us the screed depth and boiler setup. We'll diagnose remotely if we can, or send someone with a thermal camera.