When it comes to autonomous gas boilers for heating water in caravans and motor homes, the family of boilers from the German manufacturer Truma is more often mentioned. From the 80s to the present day, the modification of the gas boiler Truma B10 is used by caravaners throughout Europe.
The modern line of boilers Truma includes models:
- B10 - gas boiler of 10 liters
- B14 - gas boiler of 14 liters
- B10 EL - gas boiler with electric ten, 10 liters volume
- B14 EL - gas boiler with electric ten, volume of 14 liters
Technical characteristics of the gas boiler Truma B10:
- The working range of water heating gas burner - 30 ° C-70 ° C
- Power of a gas torch - 1500 W
- Operating voltage for gas burner - 12V
- Power of electric teng - 850 W
- Operating voltage for electric heating element - 230V
- Operating gas pressure - 3 mbar
- Maximum water pressure - 2.8 Bar
- Water heating time from 15 ° C to 70 ° C:
- gas burner - 34 min. (model B10, B10EL), 50 min. (model B14, B14EL)
- electric teng - 45 min. (model B10, B10EL), 72 min. (model B14, B14EL)
- gas burner and electric heater - 25 min. (model B10EL), 38 min. (model B14EL)
- Empty boiler weight - 6.7 kg.
For more information on features and installation, see the documentation section.
Principle of operation
The gas burner is controlled by an electric switch, which is connected by a special wire to the electrical circuit of the gas boiler.
A separate wire to this board is supplied with a voltage of 12V from the caravan battery. It should be noted that when connecting the boiler polarity is important. Otherwise, incorrect connection leads to blown fuses on the electrical board.
The switch has 2 positions (on / off), a regulator for a smooth change in operating temperature (30 ° C - 70 ° C), as well as 2 LEDs. After pressing the switch to the "on" position, the green LED lights up. The system supplies a spark to the burner using an external voltage of 12V, and also opens the gas supply to the burner using an electromagnetic valve.
If within 5 seconds from the moment of switching on for some reason (no spark or gas) the gas cannot be ignited, the system automatically blocks the gas line and stops supplying the spark to the burner. On the switch along with the green LED lights up red. The flame detection factor is the receiving (longer) electrode on a gas burner, which when ignited (the electrical conductivity of the plasma produced during ignition is much higher than the electrical conductivity of air) comes in a spark from the transmitting (shorter) electrodes.
Attempts to start can be repeated by moving the switch to the "off" position, and then "turn on" again. If the burner starts successfully, the green LED remains on the switch. This means that the burner has started and is heating up.
When the maximum heating temperature is reached, the built-in thermostat through the burner solenoid valve shuts off the gas supply, the green LED goes out and the red light comes on. When the water cools down, and exactly as when opening the tap and the beginning of its use, the thermostat reacts to a drop in temperature and the process of starting and heating is repeated again. The thermostat on this boiler uses the property of some materials to significantly change its electrical resistance depending on the temperature. NTC resistors used in this thermostat are made of such materials. It is placed in the active zone of the thermostat, the signal from which is removed by the conductor and fed to the electric amplifier, and then to the comparator. He compares the resistance of an NTC resistor and a variable resistor having a temperature scale. The result of the comparison is the opening or closing of the solenoid valve, as well as high-voltage ignition.
As you can see, the process of heating water is fully automatic. You only need to turn on the power on the switch once, the gas boiler will perform the rest of the work for you. Updating the water in the boiler is also automatic. When the valve is opened, the electrical switch closes (or the pressure switch depending on the system), the water pump turns on and supplies water from the tank to the lower inlet of the boiler. Cold water pushes hot water out of the top outlet that goes to the faucet.
Disassembly of the boiler
We remove the external heat-insulating casing. To do this, remove the top and bottom plastic covers (by unscrewing 3 screws on each), remove the rectangular duct cover (4 screws), and then open the cover.
Remove the water tank (in common "pot"). To do this, it is necessary to remove the circular clamp connecting the tank with the base of the boiler.
Disconnect the gas burner. To do this, remove the duct body (2 screws and 4 nuts) which holds the gas burner.
Attention should be paid to the lower drainage "nose", welded to the base of the boiler. When the boiler "freezes", when the upper water tank becomes non-hermetic as a result of freezing of water in it in winter, the thawed water flows to the bottom of the boiler base and through the spout is brought to the street. This simple design, in case of depressurization, will leave the floor of your home on wheels dry. You should periodically clean the drain "spout" of dirt and dust.
Disconnect the burner from the airway panel (2 screws).
List of possible faults
|No power supply||No 12V power supply, fuse blown.||Check the power supply or replace the fuse.|
|Constantly blown fuse||Wrong polarity when connected.||Correct polarity.|
|Red LED is on. Boiler does not start. Or it starts and shuts down.||No gas, no water, put the cap on the exhaust grill.||Fill with water, fill the cylinder with gas, remove the cap from the exhaust grille.|
|Boiler does not restart||Faulty gas solenoid valve. When the boiler is turned off, the tap does not close to the end and the flame continues to burn weakly.||Close the gas cylinder and perform the operation again. If everything repeats, replace the gas valve (without solenoid coil).|
|Boiler "flows"||Water tank lost its tightness.||Make a leak or replace the tank.|