PlumbParts AI — by Plumbstargas Ltd

Choose one

Manufacturer

Model

Safety concern?Gas smell, CO alarm, fumes, damaged flue or water on electrics.

QUICK COMPONENT HELP

Need to test a component?

QUICK INSTALLATION GUIDE

System boiler → combi

Survey first, then plan the conversion. Expand each stage for the checks that matter.

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Suitability comes firstA larger combi cannot compensate for an inadequate mains supply. Measure flow and dynamic pressure, establish simultaneous hot-water demand and compare them with the proposed appliance data.

Engineer planning aid for domestic gas installations in England. Gas work and appliance commissioning require appropriate Gas Safe registration and competence; electrical work requires electrical competence. Use the exact installation manual and the regulatory requirements applicable to the job.

BEFORESystem boiler + cylinder

Boiler heats radiators and the cylinder coil. Stored domestic hot water supplies the taps.

AFTERCombi + direct hot water

Sealed heating circuit remains separate. Mains cold water passes through the combi to hot-water outlets.

See the conversion at a glance

RETAIN / verifyREMOVE / decommissionNEW / reconnect

Typical indirect-cylinder arrangement. Trace the actual system first: cylinder supply can be mains-fed or cistern-fed. Dashed red lines mark redundant coil branches; line colours describe circuits, not wire colours.

Before · identify what comes out

After · reconnect to the combi

Gas → combi gas inlet

Verify / upgrade supply by calculation and tests for maximum appliance input. No assumed pipe size.

Combi flue → approved terminal

New approved flue system; verify route, lengths and clearances from the exact manual.

Condensate outlet → suitable drain

Plan fall, material, termination and frost protection to manufacturer instructions.

PRV outlet → safe discharge point

Provide the specified safety discharge route. Condensate and PRV routes have different requirements; combine only where an approved arrangement explicitly permits it.

Heating controls → compatible boiler input

Retain required heating zones and interlocks. Replace / configure the control as needed; remove redundant cylinder-stat and hot-water channel functions.

Pump / tank-fed services → review

Remove incompatible gravity shower pumps. Do not remove a cistern still feeding retained services. Avoid redundant dead legs.

Functional overview, not a physical pipe layout or installation specification. Gas, flue, electrical wiring, filling arrangement and safety connections are listed separately. Verify every appliance connection in its exact manual.

Pause the conversion if…

The mains cannot meet demand; several showers must run together beyond the combi capability; existing fittings cannot tolerate mains pressure; a safe gas, flue, condensate or discharge route cannot be achieved; or the heating system cannot meet the new boiler’s requirements. Resolve the design or retain an appropriate cylinder solution.

Official references

Reviewed 12 October 2026. These references support survey and compliance checks; this overview does not replace the selected boiler’s installation instructions.

FAULT CODE LOOKUP

Find the code. Prove the fault.

Use the code as a starting point, then confirm the failed stage before changing a part.

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Manufacturer

Model

Fault code

Available codes

Model check: Code meanings can vary by boiler generation. Confirm the GC number or serial number and use the exact manufacturer instructions.

SERVICE / TEST MODE

Match the boiler before entering service mode.

Select the appliance and record its identifier. The guide will show the correct manufacturer terminology and build an exact official-manual search.

⚙

Gas Safe engineers onlyService, chimney-sweep and combustion-test modes can force the appliance to a fixed firing rate. Monitor the appliance continuously and follow the exact installation and servicing instructions.

Manufacturer

Model

GC, serial or article number Required

Why the identifier is required: A family name can cover several control panels. Never use a remembered button sequence from a different generation. Confirm maximum/minimum-rate selection, time limit and exit method in the exact appliance instructions.

ROOM THERMOSTAT INSTALLATION

Match the control before wiring it.

Select the thermostat, heating system and boiler control input. The guide will build the installation, pairing and proving sequence.

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Identify every conductorPhotograph and label the existing wiring. Confirm whether the boiler needs a 230 V switched live, volt-free contact, OpenTherm or a manufacturer-specific control before moving any wire.

Thermostat

Product / receiver

Heating system

Boiler control input

Boiler make, model and GC / serial number Required

Compatibility check: Do not connect a 230 V output to volt-free, OpenTherm, eBUS or other low-voltage terminals. Retain or remove boiler links only as shown in the exact appliance instructions.

REPLACEMENT PCB SETUP

Match, code and commission the replacement board.

Record the exact appliance and both PCB numbers before using any coding value, code plug or parameter set.

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Do not guess a codeA board may fit several boilers but still need a model-specific identity, coding plug, parameter set or combustion calibration. The wrong setup can create unsafe operation or damage another component.

Manufacturer

Model

GC, serial or article number Required

Old PCB part number Required

Replacement PCB part number Required

Old code / parameter recorded before removal Optional

Final authority: Use only the coding value, plug, memory device or parameter set specified for the exact boiler and replacement PCB. If the old board cannot be read, obtain the value from the manufacturer’s technical information—not from a similar boiler.

PART IDENTIFICATION

Identify the part before ordering.

Match the appliance and old component details after the diagnosis has been confirmed.

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Diagnosis firstA fault code can point to a system condition, wiring or configuration—not necessarily a failed part.

Manufacturer

Model

Confirmed component Required

GC number or serial number One required

Number on the old part One required

IDENTIFICATION REQUIRED

Select the confirmed component

?

Complete the appliance and component details. Add the GC, serial or old part number before ordering.

1 · ApplianceManufacturer and model

2 · ComponentConfirmed failed component

3 · Exact matchGC, serial or old part number

SUPPLIER COMPARISON

Check today’s total cost

Enter prices including VAT

Open each merchant, search using the copied appliance and part details, then record the current price and stock.

LOWEST ENTERED TOTALNo prices enteredAdd at least one VAT-inclusive price to compare suppliers.

Before fitting: Check the merchant or manufacturer supersession, connectors, ratings and included seals against the exact appliance instructions.

OFFICIAL DOCUMENTS

Find the right appliance manual.

Build an exact search, then open the manufacturer’s own document library.

▤

Match the generationModel names can cover several appliances. Record the GC, serial or article number whenever it is available.

Manufacturer

Model

GC, serial or article number Required

Document needed

MANUAL SEARCH READY

Installation & servicing instructions

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Open official library ↗

Installation & servicingCommissioning, service procedures, settings and technical data.

Fault-findingCode definitions, operating sequence, test points and expected values.

Parts informationExploded diagrams, assemblies and identification references.

Operating instructionsUser controls, resets and normal appliance operation.

Engineer check: Use the document revision for the exact appliance. Test values, wiring, fault meanings and component procedures can change between generations.

PLUMBSTARGAS LTD

Prepare a customer quotation.

Enter the job details and costs, then copy a WhatsApp-ready quotation or save it as a PDF.

£

1 Customer and reference

Quote number Required

Issue date Required

Valid until Required

Customer name Required

Telephone or email

Job address Required

2 Work and price

Job title Required

Scope of work Required

Labour (£) One cost required

Materials (£) One cost required

Other cost description

Other (£) One cost required

Quotation total No VAT added£0.00

3 Terms and notes

Payment terms

Notes or exclusions

Where does the boiler stop?

Choose one

Is there a demand for heating or hot water?

What happens before it stops?

What is not working?

Need to test a component?

System boiler → combi

See the conversion at a glance

Before · identify what comes out

After · reconnect to the combi

Find the code. Prove the fault.

Quick checks

Match the boiler before entering service mode.

Match the control before wiring it.

Wiring diagram

Match, code and commission the replacement board.

Identify the part before ordering.

Select the confirmed component

Check today’s total cost

Find the right appliance manual.

Installation & servicing instructions

Prepare a customer quotation.

1 Customer and reference

2 Work and price

3 Terms and notes

Conversion diagram

Wiring diagram

Do not continue normal diagnosis