Cold spots in the home are common during the heating season, and many households in Bordon, Whitehill, Liphook, Alton and Farnham experience them every year. The good news is that many causes of cold radiators and unbalanced heating can be identified and corrected with simple DIY steps. This guide explains what to look for, how to put things right, and when to call a professional.
Understanding the causes of cold radiators and unbalanced heating
When some radiators heat up fully while others stay lukewarm or completely cold, it usually comes down to one of a few common issues:
- Trapped air
- Sludge build-up
- Incorrect valve settings
- Pump speed or circulation problems
- Poor system balancing
In older properties around GU35, GU34 and GU9, these problems can be made worse by ageing pipework or changes to the heating layout over time. Before making any adjustments, it helps to start with a few simple checks.
Quick checks you can do now
These straightforward checks often identify the cause of the problem within minutes:
- Is your boiler pressure between 1.0 and 1.5 bar?
- Are all radiator valves fully open?
- Do your room thermostats and TRVs call for heat?
- Is the boiler running without fault indicators?
If anything is off, correct it first and re-test the system. If the issue persists, move on to more targeted troubleshooting.
Bleeding radiators to remove trapped air
A common cause of cold radiators is trapped air, particularly if the top of the radiator feels cold while the bottom is warm. Bleeding allows air to escape so hot water can flow properly.
To bleed a radiator:
- Turn the heating on and wait for radiators to warm.
- Switch the heating off, then locate the bleed valve.
- Use a radiator key to open the valve slowly.
- Let the air hiss out until water flows steadily.
- Close the valve firmly but gently.
After bleeding several radiators, check the boiler pressure again and top up if required. Homes in multi-storey layouts—common in parts of Liphook and Alton—often need bleeding more regularly due to air migrating upwards in the system.
Checking TRVs and lockshield valves
Thermostatic radiator valves (TRVs) regulate the flow of hot water into a radiator. If they stick or seize, the radiator may stay cold regardless of boiler operation. Gently removing the TRV cap and pressing the pin a few times can help loosen it.
Lockshield valves sit on the opposite end of the radiator and control how much water flows through the circuit. Their position is crucial for avoiding cold radiators and unbalanced heating, especially in longer pipe runs such as those found in larger homes around Farnham.
Before adjusting the lockshield valve, note its starting position so you can return it if necessary. These valves are sensitive, and even small changes affect flow.
How to balance your heating system for even warmth
Balancing ensures all radiators receive an appropriate share of hot water. Without balancing, the radiators closest to the boiler often get too much flow while distant ones remain cold.
To balance a system yourself:
- Turn on the heating and allow all radiators to warm slightly.
- Identify radiators that heat too quickly; partially close their lockshield valves.
- Open lockshield valves further on radiators that lag behind.
- Make small adjustments and recheck after 15–20 minutes.
This process can take time but often restores even temperatures throughout the home. Properties in GU35 and nearby areas with extensions or loft conversions may especially benefit from a proper rebalance.
Dealing with sludge and circulation issues
If a radiator stays cold at the bottom but warm at the top, sludge is usually the culprit. This build-up restricts water flow and reduces heating efficiency. While mild sludge might respond to DIY flushing attempts, significant debris often requires professional cleaning.
Circulation issues can also stem from the heating pump. If the pump speed is too low, radiators far from the boiler may struggle to warm. Increasing the pump setting by one level can sometimes resolve this, but only do so if you are confident identifying the pump controls.
If in doubt, continue with the remaining troubleshooting steps rather than adjusting pump speeds excessively.
Checklist: When to call a professional
- You suspect heavy sludge in the system.
- Radiators stay cold even after bleeding and balancing.
- Lockshield valves appear damaged or seized.
- The pump is noisy, excessively hot or not circulating properly.
- Boiler pressure drops repeatedly.
Homes in Bordon and Whitehill with older heating systems may reach a point where DIY adjustments can only do so much, and a deeper professional investigation is the safer option.
Maintaining an even and efficient heating system
Once you resolve cold radiators and unbalanced heating, routine maintenance helps keep things running smoothly. Bleed radiators annually, check TRV movement at the start of heating season, and monitor boiler pressure monthly. In areas such as Liphook and Alton, where hard water is common, consider inhibitor additives to protect the system from corrosion and sludge.
Even small improvements to flow and temperature balance can significantly increase comfort while reducing boiler workload and energy bills.
For reliable help with persistent cold radiators and unbalanced heating, book a visit at https://www.embassygas.com/book.