Waste/Multi Oil Burner

Can I fit a Kroll waste / multi oil burner onto my existing boiler?

A Kroll KG/UB waste / multi oil burner from Flexiheat UK is a great way to significantly reduce your heating costs. With its ability to burn almost any used oils from waste engine oils and hydraulic oils to used vegetables oils and Bio Diesel.  In fact, our range of waste/multi oil burners are so universal that they can also burn 100% rape seed oil and heating oils.  Because of these wonderful advantages, more and more people are looking to replace their existing oil burner with one of our KG/UB burners.

Below, we have set out a variety of questions which should help you decide if a waste / multi oil burner is suitable for your existing appliance.


1. Will the KG/UB burner fit onto my existing boiler? Please check the dimensions, especially the dimensions of the “holes of the burner plate” and the “dimension of the burner tube”. If these dimensions correspond to the dimensions of the burner’s flame tube, the burner flange can be connected. Please check the below paying particular detail to dimensions “E” and “G”. If the burner tube will fit and you can pick up the burner mountings (G) which have a range due to the slotted burner mounting flange

Download technical details of the KG/UB burners


2. The minimum combustion chamber diameter is 180mm The minimum combustion chamber length must be –

KG/UB20P = 300 mm

KG/UB20 = 320 mm

KG/UB55 = 360 mm

KG/UB70 = 360 mm

KG/UB100 = 380 mm

KG/UB150 = 400 mm

KG/UB200 = 400 mm


3.Construction of your Boilers Combustion Chamber;-

We have developed and patented our “ZVP” burner tube. This acts like another combustion chamber, within a combustion chamber, ensuring higher efficiency, better combustion, lower flue gas temperatures and longer maintenance periods

ZVP Tube
The following picture shows one of our 200kW waste / multi oil burners with our ZVP tube attached

Waste / Multi Oil Burner


The ZVP burner tube ,which is attached directly to the burner comes with a ceramic mat for combustion chambers with convex rear as standard or a 500mm x 500mm ceramic fiber board for combustion chambers with a vertical rear panel

 Download drawing of combustion chamber variants


4. The Kroll waste/multi oil burners range require a compressed air supply. This is neither a large amount of air (cfm) nor a high pressure (1.5 Bar Maximum). Kroll produce a whisper quiet compressor, which is extremely quiet and compact (roughly the size of a briefcase), this compressor is controlled by the burner, and is only in use when the burner has a demand. You can utilise your own compressor, as long as it meets the requirements of the burner, and you fit a good quality filter, regulator, water trap prior to the burner.


5. We would recommend that your existing flue system is at least, 4 meters, and includes an open terminal and a draught stabilizer,  required. See below drawing of our recommended flue kit we can supply you if so required

Download recommended flue kit configuration for a waste oil boiler


For more information on our waste / multi  oil burner range, please click here  Alternatively, please give us a call on 01202 822222 and our dedicated sales team will be happy to offer advice and assistance or just contact us by mail by clicking   here