Installation and servicing guide for Alpha CD25C, CD28C and CD35C wall‑mounted, fan‑assisted, high‑efficiency condensing combination boilers.
This document provides the full set of instructions for installing, commissioning, operating and servicing the Alpha CD25C, CD28C and CD35C high‑efficiency condensing combination boilers. It includes technical data, safety regulations, wiring diagrams and fault‑finding procedures.
Key sections cover boiler dimensions, gas and electrical supply requirements, flue system design, central‑heating system setup, boiler location, and routine maintenance. A benchmark checklist and service record form are also provided to help installers verify compliance with UK building and gas regulations.
| Central heating load (CD25C) | 5.5 – 19.5 kW |
|---|---|
| Domestic hot water flow (CD25C) | 9.6 L/min |
| Gas rate (CD25C) | 2.55 m³/h (90.1 ft³/h) |
| Electrical supply | 230/240 V ~ 50 Hz, fused at 3 A |
| Pressure relief valve setting | 3 bar |
The boiler requires at least a 22 mm gas supply pipe.