In short
These are the questions our customers ask us most, answered the way we would answer them at your door: plainly and honestly. Each page gives practical steps you can safely try, says clearly when to stop and call a Gas Safe engineer, and links to the regulations or manufacturer guidance behind it.
Choosing a new boiler
What's the best boiler?
What is the best boiler? It depends on your budget and setup. How to choose between Baxi, Worcester Bosch and Ideal, and compare warranties and quotes.
Read the answer →What size boiler do I need?
What size boiler do you need? How combi output affects hot water flow, why heating size comes from heat loss, and why bigger is not better.
Read the answer →How do I compare boiler quotes like-for-like?
How to compare boiler quotes fairly: a like-for-like checklist covering the boiler, warranty, system clean, filter, controls, flue and what costs extra.
Read the answer →What does a boiler warranty actually cover?
What a boiler warranty covers, what it usually does not, and the conditions that keep it valid: registration, annual servicing and a clean system.
Read the answer →Heat pump or gas boiler: which is right for a Telford home?
Heat pump or gas boiler? How each works, what changes in your home, the Boiler Upgrade Scheme grant from GOV.UK and questions to ask before choosing.
Read the answer →Combi vs system boiler: which is right for your home?
Combi or system boiler? How each works, hot water flow, space, homes they suit and new boiler prices in Telford and Shropshire, from £1,750 inc VAT.
Read the answer →Boiler installation costs in Telford
What affects the price of a new boiler, from £1,750 inc VAT for a basic like-for-like installation, subject to a site inspection.
Read the answer →How long does a boiler last? Repair or replace?
How long boilers usually last, the signs it is time to replace, and when a repair still makes sense.
Read the answer →Installing and upgrading
How long does a boiler installation take?
How long a new boiler installation takes: usually a day for a like-for-like swap, longer for conversions or moves, and what happens on the day.
Read the answer →Can I move my boiler, and what's involved?
Can you move a boiler to another room or the loft? What moving a boiler involves: flue, gas pipe, condensate, access, Building Regulations and cost.
Read the answer →Do I need a system flush or a magnetic filter?
Do you need a power flush or magnetic filter with a new boiler? What Approved Document L and BS 7593 expect, chemical clean vs power flush, and costs.
Read the answer →Is it worth getting a smart thermostat?
Is a smart thermostat worth it? What smart controls do, when they help, compatibility with your boiler and what the Building Regulations say for combis.
Read the answer →What do the regulations say must be fitted with a new boiler?
Building Regulations for a replacement gas boiler in England: 92% efficiency, combi controls, TRVs, a CO alarm and the compliance certificate.
Read the answer →Do I need a carbon monoxide alarm? The rules for landlords and homeowners
When a carbon monoxide alarm is a legal requirement in England: rented homes, new boilers, which alarm to fit, where it goes and the fine for landlords.
Read the answer →More short answers: heating controls and radiators questions →
Boiler and heating problems
Why is my radiator cold at the top or the bottom?
Radiator cold at the top means air: bleed it. Cold at the bottom usually means sludge. Causes, safe checks and when to call a heating engineer.
Read the answer →Why is my boiler making a banging or kettling noise?
Why your boiler bangs, kettles, gurgles or whistles: limescale, sludge, low pressure, pump faults and air. Safe checks and when to call an engineer.
Read the answer →Why do I have heating but no hot water?
Heating works but no hot water? Common causes on combi and cylinder systems, safe checks to try first, and when to call a Gas Safe engineer.
Read the answer →Why does my boiler keep cutting out?
Boiler keeps cutting out or switching off? Common causes: low pressure, a frozen condensate pipe, thermostat, gas supply, poor flow. Safe checks to try.
Read the answer →How do I thaw a frozen condensate pipe?
Boiler stopped in freezing weather? How to find and thaw a frozen condensate pipe safely, reset the boiler, and stop it freezing again.
Read the answer →How do I bleed a radiator?
How to bleed a radiator safely: when to do it, step-by-step instructions, why your boiler pressure drops afterwards and how to top it up.
Read the answer →Why is my boiler losing pressure?
Boiler pressure keeps dropping? Common causes, the right pressure, how to repressurise a combi safely and when to call a Gas Safe engineer.
Read the answer →Boiler fault code search
Look up a code for Worcester Bosch, Baxi, Ideal, Viessmann, Vaillant, Glow-worm and Potterton boilers: what it means and what is safe to check.
Read the answer →Boiler not working? Quick checks
Five safe checks before you call an engineer: gas, power, pressure, condensate and reset.
Read the answer →Safety and servicing
What to do if you smell gas
Smell gas? Call the National Gas Emergency Service on 0800 111 999. Step-by-step UK safety advice, carbon monoxide signs and what happens next.
Read the answer →How often should a boiler be serviced?
Most boilers should be serviced every 12 months. Why it matters, what a service covers, landlord rules and boiler service prices in Telford.
Read the answer →What is the difference between a boiler service and a gas safety check?
A boiler service and a gas safety check (CP12) are not the same. What each covers, who needs which, and whether both can be done in one visit.
Read the answer →How do I check a gas engineer is Gas Safe registered?
How to check a gas engineer is Gas Safe registered: the ID card, the work categories on the back, the online register and what to ask before booking.
Read the answer →What CombiCert would check
These answers are how we talk through common jobs on the doorstep in Telford and Shropshire. On a real visit we still check the appliance, flue, ventilation and system before confirming any price. Call or WhatsApp 07393 220694, or use the quote form, if you want us to look at yours.
Can't find your question? Ask us
Send us your question with your boiler make and model, any fault code and a photo if you can. We answer as plainly as we write here, and if it needs a visit we will say so. Boiler repairs and services start from £90 + VAT; new boilers from £1,750 inc VAT for a basic like-for-like installation, subject to a site inspection.
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We cover Telford and nearby, including Wellington, Madeley, Dawley, Oakengates, Shifnal, Newport, Ironbridge and Shrewsbury.
About these answers
Can I ask CombiCert a boiler question that is not answered here?
Yes. Call or WhatsApp us on 07393 220694, or email hello@combicert.co.uk, with your boiler make and model, any fault code and a photo if you can. We are open Monday to Saturday, 08:00 to 19:45. If it needs a visit, we will tell you, and what it is likely to cost.
Who writes these boiler answers?
Peter Jefferson, director of CombiCert Ltd and a Gas Safe registered engineer, writes and reviews every answer. CombiCert's Gas Safe registration number is 621146. Where we quote regulations or manufacturer guidance, the page lists the source so you can check it for yourself.
Can these answers replace a visit from an engineer?
No. They explain what is going on and what is safe for you to check, such as pressure, radiators, thermostats and condensate pipes. Anything inside the boiler case, and any gas pipework or flue, must be handled by a Gas Safe registered engineer. If you smell gas, call 0800 111 999.
General information, not a substitute for an on-site assessment by a Gas Safe registered engineer. If you smell gas, call 0800 111 999.