Central Heating Pressure Calculator: Get Your Boiler Pressure Right
Calculate correct system pressure, expansion vessel size, and cold fill pressure for your central heating. Avoid boiler breakdowns — free tool, no sign-up.
⚡ Instant Results 🔓 100% Free ✅ No Signup 🎯 99% Accuracy 🏗️ Used by Pros
🔧 Pressure Quick Preview
🎯 Cold fill: 1.2 bar | 🛡️ Max: 2.5 bar
Stop Boiler Pressure Problems – Professional Central Heating Pressure Calculator
Wrong system pressure causes boiler lockouts, leaks, and inefficient heating. Our plumbing calculator helps homeowners, plumbers, and contractors calculate the correct cold fill pressure and expansion vessel requirements for any sealed heating system.
- ✅ Solve: Boiler pressure too low/high, frequent refilling, pressure relief valve leaks
- ✅ Precision: Calculates based on property height and system volume
- ✅ Result: Optimal cold fill pressure & expansion vessel size
Key Benefits
- ✔️ Prevent boiler breakdowns
- ✔️ Stop pressure relief valve dripping
- ✔️ Extend boiler lifespan
- ✔️ Trusted by 12,000+ UK heating engineers
⚙️ Free Central Heating Pressure Tool
Enter your system details — get correct pressure settings & expansion vessel sizing
Vertical distance from boiler to highest radiator/floor
Estimate: 10-15L per radiator (standard), 5-8L per radiator (compact)
Check vessel label — typically 0.5-1.0 bar
📊 Your Heating System Results
— bar
Hot operating pressure: — bar
Recommended expansion vessel: — litres
Status: —
📏 Ideal cold: 1.0-1.5 bar 💧 25,000+ calculations
Smart Features For Perfect Heating Pressure
Height Calculation
Accounts for building height (0.1 bar per metre).
Volume-Based Sizing
Calculates expansion vessel correctly.
Temperature Expansion
Water expansion factor based on max temp.
Vessel Pre-charge
Accounts for existing vessel settings.
Pressure Status
Shows if your system is within safe range.
System Type
Works for sealed or open vented systems.
Mobile Ready
Check pressure on the go.
100% Free
Unlimited calculations, no signup.
How The Central Heating Pressure Tool Works
1️⃣ Enter property height & system volume
2️⃣ Select max temperature & system type
3️⃣ Add expansion vessel pre-charge
4️⃣ Get cold fill & operating pressure
Why Use Our Heating Pressure Calculator
⚡ Instant Diagnosis
Know if your pressure is wrong.
Know if your pressure is wrong.
🎯 Precision
Stop guessing pressure settings.
Stop guessing pressure settings.
💰 Save £££
Avoid boiler breakdowns.
Avoid boiler breakdowns.
🚫 No More Leaks
Prevent PRV dripping.
Prevent PRV dripping.
🏆 Professional
Method used by Gas Safe engineers.
Method used by Gas Safe engineers.
Perfect For Every Heating System
🏠 Homeowners
- Check if boiler pressure is correct
- Understand why pressure drops
- Know when to repressurise
- Prevent costly breakdowns
- Improve heating efficiency
🔧 Plumbers
- Quick system commissioning
- Expansion vessel sizing
- Diagnose pressure issues
- Professional reports for clients
- Reduce callback complaints
🏗️ Contractors
- New build commissioning
- Multi-storey properties
- Large commercial systems
- Meet building regulations
- Reduce installation errors
🛠️ DIY Enthusiasts
- Learn pressure principles
- Top up pressure correctly
- Understand expansion vessels
- Avoid over-pressurising
- Save on service calls
Why Choose Speedy Jet Plumbers?
👨🔧 Real plumbing experts – Gas Safe registered engineers
🏆 Trusted by 5,000+ UK homeowners & businesses
⚡ Fast response – emergency same-day service
💰 Affordable transparent pricing & free estimates
🔧 Free tools + honest advice, no hidden agenda
Central Heating Pressure FAQs
What should my boiler pressure be?➕
For most UK homes, cold fill pressure should be 1.0-1.5 bar when the system is cold. When heating runs, pressure may rise to 2.0-2.5 bar — this is normal expansion. Use our calculator for your specific property height.
Why does my boiler pressure keep dropping?➕
Common causes: leaks in pipework or radiators, faulty expansion vessel, air in system, or PRV leaking. Our calculator helps diagnose if pressure settings are correct.
Do I need to sign up to use this tool?➕
No signup, no email required. 100% free tool with unlimited calculations.
How does building height affect pressure?➕
Every 10 metres of height requires approximately 1 bar of pressure to lift water. A 3-storey house (~8m) needs at least 0.8 bar plus 0.3 bar margin = 1.1 bar minimum.
What size expansion vessel do I need?➕
Standard rule: 5-8% of total system volume. 100L system needs ~8L vessel. Our calculator gives exact recommendation based on your volume and temperature.
How do I repressurise my boiler?➕
Locate filling loop under boiler, open both valves until pressure reaches our recommended level (usually 1.2-1.5 bar), then close. If pressure drops quickly, you may have a leak.
Can Speedy Jet Plumbers fix my pressure problem?➕
Absolutely. We diagnose and repair all pressure issues: expansion vessel recharging, leak detection, PRV replacement, and full system repressurisation across the UK.
What happens if pressure is too high?➕
Over 2.5 bar cold can damage boiler components and cause pressure relief valve to discharge water. Over 3 bar may trigger boiler lockout. Use our calculator to find safe range.