Boiler, cylinder and hot water guides
Boilers and cylinders need to work with the property around them. These guides explain replacement choices, survey preparation, supply and control considerations, and the records to keep after the work.
64 guides
Articles and fault guides
Baxi E133 fault: preparing for fault diagnosis
Understand Baxi E133 in its correct model group, separate a fault description from a diagnosis and prepare useful details for a safe boiler repair visit.
Read thisBoiler condensate pipe routing for planned work
Plan boiler condensate drainage before moving or replacing an appliance. Compare internal and exposed routes, access, freezing risks and waste connections.
Read thisWhen a boiler condensate pump needs attention
Recognise condensate pump problems, report useful symptoms and arrange safe inspection of the pump, discharge route and boiler shutdown connection.
Read thisKettling and unusual boiler noise: repair or system investigation?
Describe boiler kettling, rumbling or banging clearly and understand how an engineer separates appliance faults from circulation and wider system issues.
Read thisWhy does a boiler lock out again after a reset?
A boiler that locks out again needs its fault history investigated. Learn what to record, when to stop using it and how to prepare for a repair visit.
Read thisNew boiler noise after a service: what to report
Report new boiler noise after servicing with a useful timeline, operating details and safety signs, so the follow-up addresses the actual change.
Read thisHow parts availability changes a boiler repair decision
Assess boiler repair options using the exact failed part, confirmed supply, repair checks and likely disruption rather than the boiler’s age alone.
Read thisWhy is boiler pressure rising when the heating is off?
Boiler pressure rising while heating is off needs the cold-pressure pattern checked. Understand filling and expansion clues without opening or draining it.
Read thisWhy a replacement boiler needs the existing system assessed
Plan system assessment, cleaning and water treatment with a boiler replacement. Understand the evidence, access, method and handover records needed.
Read thisAccess a boiler engineer needs for a service
Prepare for a boiler service with clear working space, meter and control access, and information about cupboards, concealed flues and shared areas.
Read thisShould a boiler be serviced before a home sale?
Planning a home sale? Separate boiler servicing, missing maintenance records and a buyer’s inspection, then arrange the right visit before moving.
Read thisWhat happens if a boiler service finds a defect?
Understand a defect found during boiler servicing: the safety instructions, repair approval, parts, follow-up checks and records to keep afterwards.
Read thisBoiler service records and installation handover
Keep records after installation, servicing and repairs. Understand commissioning details, service history, warranty information and landlord records.
Read thisBoiler servicing and a landlord gas check: what differs?
Understand the difference between a boiler service and landlord gas safety check, the records each produces and how to book both visits together.
Read thisBoiler switching on and off frequently: what needs investigating?
Frequent boiler starts can involve heating demand, controls or circulation. Learn what to record and how to plan diagnosis before replacing equipment.
Read thisBoiler warranty and guarantee: what to check before buying
Compare boiler cover by its actual terms: registration, servicing, parts, labour, exclusions and claims, rather than the warranty or guarantee label.
Read thisCan weather compensation be added to an existing boiler?
Plan weather compensation for an existing boiler by checking its model, control protocol, sensor options, zones and commissioning requirements first.
Read thisBoiling-water tap problems: plumbing repair or manufacturer service?
A boiling-water tap fault may involve its tank, filter, controls or connections. Identify the system and choose the right repair route before opening it.
Read thisWhat size hot water cylinder do you need?
Choose hot water cylinder size around showers, baths, simultaneous demand and recovery. Learn what to tell the installer before selecting a capacity.
Read thisCombi or system boiler: choosing for your home
Compare combi and system boilers by hot water demand, storage space, supply and installation changes. Build a useful brief before choosing equipment.
Read thisHow an engineer assesses a cylinder expansion-vessel fault
Learn how cylinder expansion-vessel concerns are assessed, what supports repair or replacement and why a drip alone does not identify the failed part.
Read thisHot-water cylinder heat loss: insulation and installation choices
Assess cylinder heat loss using insulation condition, published standing-loss figures and exposed pipework before choosing an improvement or replacement.
Read thisChoosing a cylinder location with enough service access
Plan a cylinder location around dimensions, removal routes, connection space and future maintenance, with structural and discharge questions checked early.
Read thisCylinder pressure-reducing valve faults and poor outlet flow
Explore how an engineer distinguishes inlet valve problems from mains limitations and outlet faults, with checks before cylinder components are replaced.
Read thisHot-water cylinder recovery time: what affects the wait?
Compare cylinder recovery times using the heat source, test conditions and household demand, and distinguish slow reheating from a new hot-water fault.
Read thisWhat electrical work can a cylinder replacement involve?
Understand the electrical scope of cylinder replacement, including immersion supplies, controls, circuit assessment and records to request at handover.
Read thisWhen might a cylinder temperature-and-pressure valve need replacing?
Understand when a cylinder temperature-and-pressure valve may need replacement, why discharge needs diagnosis and what the repair scope should include.
Read thisCylinder thermostat faults: inconsistent heating and overheating
Understand cylinder temperature-control faults, separate thermostats from safety cut-outs and report useful symptoms without opening electrical covers.
Read thisWhat records support a hot-water cylinder warranty?
Keep cylinder warranty evidence, distinguish vessel cover from other components and check the exact conditions before booking a repair or replacement.
Read thisDirect or indirect cylinder: choosing the heat-source arrangement
Compare direct and indirect cylinders using your heat source, electricity arrangements, recovery needs and future plans before choosing a replacement.
Read thisElectric shower keeps cutting out: safe next steps
An electric shower cutting out needs its symptom and model identified. Recognise unsafe conditions and arrange diagnosis without opening covers or wiring.
Read thisExpansion vessel or internal air gap: how cylinder designs differ
Understand external expansion vessels and internal air-gap cylinder designs, how to identify your model and why maintenance must follow its instructions.
Read thisGlow-worm F22 fault: pressure and circulation diagnosis
Understand Glow-worm F22 using the Energy7 System reference, what pressure readings can tell you and why filling or replacing parts needs proper advice.
Read thisDoes a heat pump need a different hot-water cylinder?
Assess whether a cylinder suits a heat pump by checking its heat exchanger, operating conditions, recovery and controls before deciding to replace it.
Read thisHeating stays on when the thermostat is off
Heating continuing after the thermostat is off may involve controls, valves or normal boiler functions. Learn which observations help a repair enquiry.
Read thisPlanning stored hot water for a shared rental property
Plan hot water for a shared rental using shower timing, simultaneous demand, recovery and maintenance access, with clear assumptions for the designer.
Read thisIdeal L2 fault: what to check in the appliance information
Ideal L2 needs the correct appliance manual and fault history. Learn what the code means for Logic Code Combi ESP1 and how to prepare a repair enquiry.
Read thisMegaflo service or repair: choosing the right visit
Choose a Megaflo service, fault investigation or replacement survey using the current symptoms, model and maintenance history to brief the right visit.
Read thisPreparing your home for a Mixergy cylinder installation
Prepare a Mixergy installation with model and heat-source details, an electrical assessment, connectivity plan and clear commissioning responsibilities.
Read thisPlanning a Mixergy cylinder alongside solar PV
Plan Mixergy and solar PV together by checking the cylinder, diverter arrangement, electrical work and commissioning scope before equipment is ordered.
Read thisMoving a boiler: survey, routes and disruption
Planning to move a boiler? Assess the position, flue, drainage, pipe routes and future maintenance access before committing to a kitchen or loft layout.
Read thisPlanning a boiler flue before building work
Plan a boiler flue around the appliance, openings, inspection access and future building work. Learn what a professional survey needs to resolve first.
Read thisPoint-of-use water heater or cylinder for a remote sink?
Compare a local water heater with extending a cylinder supply to a remote sink, considering demand, electrical capacity, waiting time and service access.
Read thisPreparing your home for boiler replacement
Prepare for boiler replacement with an access, shutdown and handover checklist. Coordinate the installation with occupants and other planned building work.
Read thisRepair or replace a boiler: how to decide
Repair or replace your boiler? Compare diagnosis, parts, reliability, installation work and future heating plans before choosing a repair or replacement.
Read thisReplacing a hot water cylinder: planning guide
Replacing a hot water cylinder? Plan capacity, heating compatibility, access, safety arrangements and handover before comparing installation proposals.
Read thisCan the loft water tank be removed after a system change?
Plan retirement of a cold-water storage tank by identifying every connected outlet, the replacement supply and access arrangements before removal starts.
Read thisCan an existing cylinder work with solar thermal?
Check cylinder suitability for solar thermal, including the heat exchanger, backup heat source, controls and the questions to resolve with both installers.
Read thisWhen does a hot-water cylinder need two coils?
Understand when two cylinder coils are useful, how they differ from immersion heaters and what to confirm before combining solar and another heat source.
Read thisWhat an installer checks in a cylinder discharge route
Prepare for a cylinder discharge-route survey with model details, access and alteration records, and learn why visible pipework is only part of the check.
Read thisWhat happens during an unvented cylinder service?
Prepare for an unvented cylinder service with the right model details, access and fault history, and understand how maintenance findings become next steps.
Read thisWhat should an unvented cylinder service record show?
Read a cylinder service record: identify completed work, access limits, defects and follow-up actions without confusing it with a landlord gas record.
Read thisVaillant F28 ignition failure: safe next steps
See what Vaillant F28 indicates on the relevant ecoTEC models, which details help a repair enquiry and when a gas emergency needs immediate escalation.
Read thisVaillant F75: what the code can and cannot tell you
Understand the limits of a Vaillant F75 code, what model details to provide and how pressure, circulation and fault history shape a proper repair visit.
Read thisReplacing a vented hot-water cylinder: what must match
Compare retaining a vented cylinder with changing the hot-water arrangement, including tank height, shower compatibility, access and the replacement scope.
Read thisWorcester Bosch E9 fault: why the model matters
Understand why a Worcester E9 fault needs the full model and cause code, what observations help and how to prepare for an overheating fault assessment.
Read thisWorcester Bosch EA fault: understanding the repair enquiry
Worcester EA needs the model and additional cause code to be useful. Understand the differences and prepare the right details for a boiler repair visit.
Read thisBoiler leaking water: safe next steps
Boiler leaking water? Keep clear of wet electrics, record visible symptoms and understand why diagnosis comes before replacing parts or the appliance.
Read thisBoiler losing pressure: causes and next steps
Boiler losing pressure repeatedly? Understand visible leaks, discharge and pressure changes, record useful symptoms, and know when to arrange assessment.
Read thisHot water cylinder leaking: what to do next
Hot water cylinder leaking? Learn the difference between a vessel leak, pipe connection and safety discharge, with safe next steps and repair choices.
Read thisHot water runs cold: understand the pattern
Hot water runs cold after starting warm? Compare combi, cylinder and single-shower patterns, record safe observations and decide what needs assessment.
Read thisNo hot water but heating works: what to check
No hot water but heating works? Separate combi, cylinder and single-outlet problems, learn safe observations to make, and find the right repair next step.
Read thisOverflow pipe dripping: identify what is discharging
A dripping outside pipe may be an overflow, condensate outlet or safety discharge. Learn what to report and why it must never be capped to stop water.
Read thisTundish dripping: what the discharge means
Tundish dripping near your hot water cylinder? Understand why discharge needs assessment, what to report safely and why safety outlets must stay clear.
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