Yes, it is possible to use a combi boiler for hot water only without connecting the heating system. This can be a practical solution for temporary installations, renovations, or when prioritizing hot water needs over space heating. However, there are several important factors to consider when using a combi boiler solely for domestic hot water (DHW) purposes.
Temporary Installation of Combi Boiler for Hot Water Only
Combi boilers are designed to provide both central heating and hot water, but they can be installed temporarily for hot water use only. This is a common practice, especially during home renovations or when the heating system is not an immediate priority. By focusing on the hot water functionality, you can enjoy the benefits of a combi boiler without the need to connect the heating side.
No Heat-Side Piping Required
Some combi boiler models, such as the IBC DC, do not require any heat-side piping to provide hot water. In these cases, you only need to connect the gas, vent, hot, and cold water lines, and then power up the unit. This simplifies the installation process and makes it easier to use the combi boiler for hot water only.
Protecting the Heating Side
When using a combi boiler solely for hot water, it is essential to ensure that the heating side does not overheat. This can be achieved by hooking up a temporary primary loop or taking other precautions as recommended by the manufacturer. Consulting with a professional installer is advisable to ensure the proper safeguards are in place.
Efficiency Considerations
Combi boilers are generally efficient in providing hot water, but they may not be the most ideal choice for space heating when used solely for DHW. During warmer months, the short durations of hot water usage can mimic short-cycle operation, which can affect the boiler’s efficiency and potentially increase wear and tear on the unit.
Boiler Specifications for Hot Water Use
When selecting a combi boiler for hot water-only use, it is important to consider the output required. For example, a combi boiler with an output of 38kW or more is generally recommended for a thermostatic shower, and the mains pressure should be around or over 12 liters per minute to ensure adequate hot water flow.
Disconnecting the DHW Side
If you want to use a tankless combi boiler solely for central heating, it is possible to disconnect the domestic hot water (DHW) side. However, you must ensure that the boiler does not have any built-in hot water storage or buffer, and it must only heat the DHW based on flow-through. This configuration ensures that the boiler operates efficiently for central heating without the added complexity of the DHW system.
In summary, using a combi boiler for hot water only is a viable option, but it is crucial to follow the manufacturer’s instructions, consider the boiler’s specifications, and take appropriate precautions to protect the heating side. By understanding the technical details and potential considerations, you can successfully utilize a combi boiler for your hot water needs, even without connecting the central heating system.
References:
1. Forum discussion on installing a combi boiler without using the heating part
2. Screwfix community thread on temporarily installing a combi boiler for hot water only
3. Discussion on the efficiency of using a combi boiler for hot water only during warmer months
4. DIYnot forum thread on which boiler to use for hot water only
5. DIY Stack Exchange question on using a tankless combi boiler only for central heating