How to commission your vehicle’s combi-heating system

Commissioning the boiler is the final step in installing a combi-heating system in a vehicle conversion, and the last thing you have to do before enjoying the benefits of warm air and hot water in the habitation area.

To start with, make sure you have a full tank of fuel, the power supply is switched on and other elements such as the Bluetooth connection to your phone have been updated.

You can then manually start the commissioning process by turning your heating demand up to 30 degrees. It’s important to remember this should be heating only at this point, with no water demand.

It’s normal to see warnings flash up on the screen at this stage, often with the numbers 423 and 424. These should reset automatically or can be manually cleared once you’ve taken the necessary action, such as switching on the power after a low-voltage warning.

Once you’ve confirmed the boiler is generating heat on its main fuel supply, you can check the electrical system. Turn the temperature demand back down to zero degrees, wait a couple of minutes for any surplus heat to be released from the system, then increase your heating demand to 30 degrees with the fuel supply set to electric to start the process again.

A common issue that can arise during commissioning is a low-fuel error. If this occurs on a diesel system, try the following steps to resolve it:

• Check you have fuel in the tank
• If you have removed the sender unit, make sure it has been replenished with fuel
• Check there is around 20mm of clearance between the fuel pipe and the bottom of the tank, so the pipe isn’t being suffocated
• Take the van for a short drive to move the diesel around and ensure it’s flowing into the vehicle pipework

In the case of voltage problems, these can often be rectified by checking that the maximum length of your cable is within the tolerance of the current draw and the fuse is intact.

For more tips and information about commissioning your combi-heating system from a member of Truma’s Technical Support team, watch this video.