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Farvis - Engineering since 1840

“Quality at Trade Prices”

All Farvis Products are design copyrighted


Mk 1 - pre October 2000

Mk 2 - post October 2000

Serial numbers : 2xxx

Mk 3 - post October 2012

Serial numbers : 3xxx

Propamiser special build with bypass and remote sensing.

Other types are built to individual customer specification

There is no significant alteration to user serviceable components between the types.


THE Farvis-CTS Propamiser thermostatic control system has been designed specifically to provide a safe and efficient non-electric burner control system for use with high pressure propane gas. It uses standard Propane gas at standard pressure and there is no reduction in burner performance compared to a manually controlled burner.  The system uses an ordinary  0 - 2 bar ( 30 psi ) gas regulator.  

The heart of the Propamiser is a high pressure modulating temperature control valve which is factory set to operate between 50 oC and 275 oC with a user adjustable range of 50 oC. This valve varies the flow of gas to the burner with an accuracy as high as 0.3% in test conditions although we specify 10% to take account of fluctuations and conditions on site!  

A typical application is the temperature control of bitumen boilers and asphalt mixers. Since maximum outlet temperatures are 180 oC - 250 oC, thermostats are pre-set to operate in one of these two temperature ranges as specified at the time of order.  The operator can then vary the control temperature by 50 degrees using the temperature control knob, up to the maximum marked on the data plate.  This gives some measure of protection against operators ‘cooking’ the material. Standard ranges are shown below but we can supply specially set up units if required.

To monitor the operation of the thermostatic valve, a temperature gauge and downstream burner input pressure gauge are fitted. For correct operation it is essential that the sensor probe should at all times be surrounded by the sealant being heated and thus the thermostat pocket must always be covered.  Because the unit will only be able to monitor and control the temperature of the material when it is liquid, initial heating up must be monitored by the operator.

So that the main burner can shut off and relight automatically,  a pilot burner is fitted. This operates all the time the unit is active and is self monitoring.  If the pilot flame is extinguished, perhaps by a high wind or a low gas supply, a thermoelectric flame safety valve will shut off the gas supply to pilot and main burner and will require manual ignition by the operator once the reason for the shut down has been ascertained.

All controls are mounted in a substantial galvanised/painted steel ventilated case having a shroud front and rear to help protect the instruments from mechanical damage and spilled sealant.

For use with Farvis equipment, the Propamiser is supplied on a self contained sled with the main and pilot burner ready fitted.  This unit is placed in the boiler casing, the pilot burner is lit with a taper and the assembly then slides into the casing and is locked in position with a clip. A manual on/off valve is fitted so that the operator can shut off the main burner manually for lighting and initial start up.

At the end of the shift the complete burner, Propamiser and sled can be removed in seconds for storage off site.  As the Propamiser and burner system is entirely self contained on the sled it can be returned to your workshops for basic maintenance or to the manufacturer as an assembly for service and recalibration.

All units are given a minimum of 6 hours operation during two separate tests in the factory before dispatch and are calibrated against a traceable UKAS source.  Every Propamiser is individually checked during its main 4 hour test using the latest computer controlled logging and measuring software and each has its own individual set of performance data, build & test records.

All temperature control parts of the unit are British built by CTS.  We understand the system and we can service and repair it as well as make ‘specials’.

Please note that the unit is for sale in the EC only and has full design copyright.

Typical installation in a FARVIS 25 gallon boiler.  Unit is removable for easy service and security.



Gas type : Propane

Operating pressure :0-2 bar

Maximum Propane usage - 0.1 kg ( standby ) to  6kg/hr ( continuous full power ) - depending on conditions and  required heat input.  Saving over a standard burner is usually about 30% but this depends on the use and conditions of service.

Pilot ignition:Manual

Standard temperature ranges :

LOW TEMPERATURE UNIT :    175 - 225 oC  nominal

HIGH TEMPERATURE UNIT :   200 - 250 oC  nominal

User adjustable range :  50 oC  nominal

Temperature sensor pocket min. Bore: 15 mm

Temperature sensor pocket min. Length: 220mm

Weight: 3kg

CTS Propamiser thermostat control for bitumen boiler fitted to standard Farvis removable bitumen boiler sled.  Design copyright.