Truma gas heaters installed on campers, trailers, caravans and caravans are quite reliable and do not diminish the concept of "German quality". But when buying a release trailer from the early 90s, be prepared for the fact that problems may arise with the correct operation of the stove.
Using the example of the gas furnace Truma 3002, we analyze its main components, the principle of operation and possible malfunctions.
There are several main devices in the stove.
1. Ignition unit. It is powered by two AA batteries. With the help of such a block, an automatic ignition of the gas burner takes place. It is very convenient to use such ignition in windy weather, when, when blowing a flame with a strong gust of wind, for several seconds, until the gas closes the safety valve, electric ignition can automatically re-ignite the flame.
Sometimes the circuit board of the unit burns out. In this case, the entire unit must be replaced. You can buy this item in the store Retrailer. By the way, the electronic ignition unit can easily be replaced by a conventional mechanical piezoelectric device.
2. Truma gas burner. It has two combustion chambers, ignition (round) and main (oval). Above the ignition chamber there is a piezo-sounding device, next to it is a thermal probe.
Thermal probe serves to turn off the safety valve, which closes the main gas line in the event that the burner flame is extinguished.
3. Gas valve-valve. The valve is the main, most critical and most complex component in the Truma heating system. The faucet has a gas inlet from the main line, two outlets on the side with nozzles for gas supply to the ignition and main combustion chamber, a knob for regulating the intensity of gas supply to the burner, a protective thermostat from overheating, and a protective gas valve for shutting off the gas line.
4. Heat exchanger. Or more simply a radiator made of aluminum alloy. The exhaust system is suitable for the radiator. A decorative metal cover is placed on the radiator from the outside.
The principle of operation of the gas stove Truma
1. Turning the knob from 0 to 1 division closes the electrical circuit and the electronic ignition unit begins to apply periodic charges to the piezoelectric light, which in turn punches a spark into the burner body near the ignition chamber.
2. Turning the knob from 1 to 3 division opens the primary valve for supplying gas to the valve from the external line.
3. When the regulator is pressed downwards, the protective thermal valve opens forcibly and the gas enters the ignition (primary) combustion chamber, after which ignition occurs. 3-4 seconds after the ignition of the ignition chamber, the thermal probe heats up to the desired temperature, which allows the protective thermal valve to assume an open position, ensuring a continuous flow of gas into the burner. After that, the regulator knob is released and takes the initial upper state under the action of the spring. The flame does not go out.
4. With further rotation of the knob from 3 to 10, the gas supply valve to the main (oval) combustion chamber gradually opens.
5. After ignition of the main combustion chamber as the stove heats up, the heating intensity (and therefore the temperature) can be adjusted using the knob in the graduation range from 1 to 10.
When the heating temperature of the radiator reaches 50 degrees Celsius, the overheat protection thermostat gradually begins to reduce the gas supply to the main combustion chamber until it is completely shut off.
1. Only the ignition chamber is ignited. When you release the regulator up the flame goes out.
Cause. Most likely the thermal probe failed
the opening protective thermal valve.
You can buy this item in the store Retrailer.
2. Only the ignition chamber is ignited. When you release the regulator up the flame does not go out. When unscrewing the knob to the end, the main camera is not ignited.
Cause. Most likely in the gas valve blockage. Requires disassembly and cleaning.
3. The flame burns in both cameras, but very unstable, with noise.
Cause. On top of each of the chambers, a fine mesh of refractory metal is soldered. It serves to evenly distribute the flame over the entire surface of the burner. As a consequence of corrosion, the soldering could be peeled off, and the metal mesh would fall off. Burner replacement required. This item can be purchased at the store Retrailer
Phased disassembly of the gas valve valve
1. In a motorhome or trailer cottage. From the bottom of the trailer disconnect the valve from the main gas pipeline. Remove the safety cover of the burner, unscrew the nozzles of the ignition and main combustion chamber, unscrew the thermal probe from the faucet, and then disconnect the burner from the faucet. The crane is taken out from within the trailer dacha, upward.
2. We take out the knob-regulator from the crane, unscrew the top plastic cover (2 bolts and an iron latch).
3. We take out the electric switch of the piezoelectric ignition, take out the plastic sleeve-switch of the primary gas supply valve.
4. Unscrew the plastic base from the metal valve cover (2 bolts). We take out the overheat protection thermostat and the cap with a splined connection.
5. Remove the metal valve cover. We take out the valve of the primary gas supply. The photograph shows dirt and bronze oxide on the edge of the main combustion chamber valve. All this needs to be cleared. Ideally, when removing the metal cover from the body of the valve, the valve of the main combustion chamber under the action of the spring should "shoot" forward. This picture does not occur due to bronze oxide.
6. After cleaning the valve wall of the main combustion chamber, remove the valve. It is necessary to completely clean and flush the valve-valve body in gasoline (kerosene), purge all channels, and clean all valves from contamination. Collect the valve valve should be in the reverse order.
The crane valve from the Truma 5002 stove and its modifications is completely similar. The difference is only in dual gas injectors.
Retrailer uses the special foaming agent Multitec from the Danish manufacturer Unipak to check the sealing of the connections in the gas pipeline of trailers and autocars. Multitec even detects small leaks, determined by the "boiling up" of the compound in places where the connection is not tight.