Case Study

Future fuels case study: converting a boiler to HVO operation

With industry efforts focused on securing amendments to the Government’s proposed energy bill to include liquid fuels in the decarbonisation of home heat, this case study, submitted by Grant, demonstrates the ease with which an oil-fired boiler can be converted to HVO operation.

A case study from Grant UK demonstrates the ease with which an oil-fired boiler can be converted to HVO operation

Here we follow the HVO conversion of a Grant Vortex oil-fired boiler.

All of Grant’s floor standing Vortex oil-fired boilers are compatible with Hydrotreated Vegetable Oil (HVO) biofuel. The process of converting to HVO operation is straightforward and can be carried out as part of the boiler’s annual service.

This step-by-step case study takes a closer look at the HVO conversion process.

Step 1: Turn off the boiler, isolate the electrical supply and shut off the oil supply.

Step 2: The existing oil tank will need to be drained of kerosene and any water/sludge removed before being replenished with HVO biofuel.

Step 3: Remove the existing oil filter from the tank and replace it with a biofuel compatible oil filter.

Step 4: Remove the burner from the boiler. If the burner is no more than 10 years old it should already be fitted with a biofuel compatible pump (marked BI0). If not, it should be replaced with a biofuel compatible pump. Clean and remove any debris or water contamination from an existing pump before using it on HVO.

Step 5: Remove the burner head and diffuser. Replace the existing oil nozzle with the correct specification of nozzle for HVO for the required boiler output, referring to for details. Refit the diffuser, check electrode setting and refit burner head.

Step 6: Replace the flexible oil line with a new one that is HVO compatible. Note that all flexible oil lines currently supplied by Grant UK are HVO compatible.

Step 7: Refit the burner to the boiler. Switch on the oil and electrical supply to the boiler. Switch the boiler on. Check and adjust the oil pressure to the correct value for the required boiler output (referring to

Step 8: Check the smoke number is 0-1 and run the boiler for at least 20 minutes. Using a digital combustion gas analyser, check and adjust the air setting to get the required percentage of CO2 in the flue gases. The HVO conversion process is then complete.

For further information, please visit