A Comprehensive Guide to Back Boilers on Boat Stoves

When it comes to heating options for boats, back boilers are a popular choice. These ingenious systems combine the functions of a stove and a central heating unit, efficiently distributing heat throughout the vessel. In this comprehensive guide to back boilers on boat stoves, we’ll explore what back boilers are, how they work, and the different types available, including pumped back boiler systems with pipe thermostat control and gravity-fed systems. Let’s dive in!

What are Back Boilers?

Back boilers are specialized attachments that can be added to existing boat stoves. Essentially, they are heat exchangers designed to harness some of the heat produced by the stove and transfer it to a coolant water based heating system, allowing for enhanced warmth distribution throughout the boat.

A Back Boiler on a Bubble boat stove.

How do Backboilers Work?

Backboilers utilize the principle of heat transfer through conduction. As the stove is lit and begins to generate heat, this heat is conducted through the back boiler coils or heat exchanger, which are in direct contact with the burning fuel. The coolant water within these coils or heat exchangers absorbs the heat and is circulated throughout the boat, providing a comfortable and consistent source of warmth.


For quotes and bookings call 07846 274 926 or email marineheatingsolutions@gmail.com


Pumped Back Boiler Systems with Pipe Thermostat Control

A popular choice for boats, pumped back boiler systems offer good control over boiler temperature and heat distribution. These systems consist of a back boiler, a circulation pump, and a pipe thermostat.

The circulation pump ensures circulation between the back boiler and radiators, and/or calorifier, maintaining a continuous flow of heated coolant water. The pipe thermostat switches on the circulation pump automatically when the back boiler has reached a set temperature. This ensures that coolant water is circulated when the stove is in use and prevents overheating of the back boiler.

Pumped back boiler systems provide excellent heat distribution, thanks to the forced circulation of heated coolant water. This type of system is particularly suitable for larger vessels or those with multiple radiators, as the pump can effectively deliver heat to different areas.

Gravity-Fed Back Boiler Systems

Gravity-fed back boiler systems are another option for heating boats. These systems operate without the need for an electric water pump, relying instead on the force of gravity to circulate heated water.

Gravity-fed backboilers work in a straightforward manner. As the stove generates heat, hot water rises naturally through the back boiler coils or pipes due to the principle of convection. As hot coolant water rises, cooler coolant water from the radiators flows back towards the stove, creating a continuous flow.

One significant advantage of gravity fed back boiler systems is their simplicity and reliability. Since they don’t rely on electrical components, there are no concerns about power outages or mechanical failures. Additionally, gravity-fed systems tend to be more energy-efficient and require less maintenance compared to pumped systems.

However, it is essential to consider the limitations of gravity-fed systems. Due to the reliance on gravity, these systems may not provide the same precise control over temperature and heat distribution as their pumped counterparts. They also might not be suitable for larger vessels or those with multiple heating zones, as the passive circulation of heated water may not be sufficient to reach every area adequately. They also require part of the pipework to run at a higher level, making it more difficult to hide pipes from view.

Hybrid Systems

Hybrid systems, incorporating a diesel heater or gas boiler into the back boiler system, offer a versatile solution in situations where only a small amount of heat is required or when running the stove would result in excessive heating of the boat cabin. These systems are especially useful for boats equipped with a calorifier, as they allow for the heating of the calorifier only to produce hot water during the summer months.

By integrating a separate diesel heater or gas boiler into the back boiler system, boat owners have the flexibility to control heat output more precisely. This is particularly beneficial when a lower heat output is desired or when the ambient temperature is already warm. Diesel heaters and LPG boilers can have a thermostat fitted to keep the boat cabin temperature at a constant level overnight, without the need to refuel a solid fuel stove or adjust the settings on a diesel stove.

In the case of systems with a calorifier, the incorporation of a diesel heater or gas boiler allows for the selective heating of the calorifier to produce hot water only. This is especially advantageous during the summer when the cabin does not require additional heating, but hot water is still needed for various purposes.

Hybrid systems provide boat owners with the ability to fine-tune their heating requirements, ensuring optimal comfort and efficiency throughout different seasons and weather conditions. These also ensure that a backup heat source is available should one of the appliances suffer a breakdown.

It is advisable to consult with a trained professional to determine the most suitable hybrid heating system for your boat and to ensure it is installed correctly and functions safely.

Stoves with Backboilers We Sell and Install

At Marine Heating Solutions we offer a range of stoves with backboilers. Here are some of the models we sell and install:

  • Bubble Diesel and Solid Fuel Stoves and Range Cookers: These 4 to 5kw stoves feature 1kw and 2kw backboilers, making them suitable for medium to large size vessels. The Bubble stoves and range cookers provide both heating and cooking capabilities, ensuring convenience and warmth on your boat.
Bubble Stove
  • Salamander Solid Fuel Stoves and Cooking Ranges with Small Sideboilers: Designed for small to medium size boats, the Salamander Hobbit Stove and the Little Range Cooker come with small side boilers that add an extra heating element. They are efficient and compact, ideal for maximizing space on your vessel.
Salmander Stoves
  • Refleks Diesel Stoves: Our range of Refleks Diesel Stoves offers options for small, medium, and large boats. These stoves are known for their reliability and versatility, providing you with customizable heating solutions based on your boat’s size and heating requirements.
Refleks Diesel Stove

Important Safety Considerations

It is crucial to note that while boat stoves with back boilers offer efficient heating solutions, they can be potentially dangerous and explosive if installed incorrectly. Therefore, it is highly recommended that the installation of back boiler heating systems be carried out by trained professionals with experience in marine heating systems.

Boat owners should exercise caution and thoroughly check the credentials and qualifications of engineers before booking them to install a back boiler heating system. Hiring a certified professional ensures that the installation is done correctly, adhering to safety regulations and minimizing the risk of accidents or malfunctioning.

By entrusting the installation to a trained expert, boat owners can have peace of mind knowing that their back boiler system is installed securely and operating safely, providing a comfortable and reliable heat source throughout their vessel.


For quotes and bookings call 07846 274 926 or email marineheatingsolutions@gmail.com


Comments are closed.