The two 5-liter versions are known (with and without boiling water level) of the VEB Elektrogerätewerk Suhl, Elektrowärme Sörnewitz, the 10-liter device from VEB Prüfgerätewerk Medingen and the memory 80 liters of water content from VEB Berliner Spezialgeräte. The "Aquatherm" is recommended for "tailor-made" hot water preparation, in whose 5 liter glass container only needs to be heated as much water, as needed for a specific purpose. The small devices are recommended for use in the kitchen.
The 80 l storage tank is primarily used in the bathroom or. installed in a convenient place in the home, where it can be hidden away (with. B. in a niche). After application to the responsible VEB energy supply (in Berlin at BEWAG) Is it possible, to heat the water at night at a reduced rate of 4 pfennigs. In this case, a separate meter is required. The heating time from 80 liters of cold water 80 °C 8 hours.
Electrical hot water tanks work without pressure, d.h. according to the overflow principle (as well as a coal bath stove). This results in, that, in contrast to gas water heaters, they are not used as remote taps, but can only be used for a specific water extraction point. Depending on the level selected on the controller, the boiler filling is heated to the desired temperature. When the hot water valve is opened, cold tap water flows into the tank from below, what does that mean or. boiling water drains through the overflow pipe through the swivel arm.
This results, that at one ,,Electrothermia" - as the device is generally called – especially the stuffing box of the hot water valve must always be tight. Otherwise it can happen, that in the case of a longer absence (when the device is in operation) the water supply runs out and the heater then burns out, if the resoldering fuse has not responded beforehand.
As with any other water fitting, the valve disk seals of the electric water tank are subject to normal wear and tear. So if the valves have to be closed by force, so that it no longer drips at the spout, then the sealing discs need to be replaced.
Replacing the valve disc seal
■ 14 and 7 mm wrenches
■ Rubber sealing washer 12,5 Glutos 4 Glutos 3 mm, Fiber seal 20 Glutos 16,5 Glutos 1 mm
All electric water tanks have mixer taps with the standardized upper part LAN 57 fitted. Before starting the repair work, the water shut-off valve upstream of the storage tank must be closed; in addition, the power supply must be interrupted.
After the two cross handles (operating handles) the fitting were pulled forward with a short jerk, the upper part can be unscrewed with a size 14 key. Caution is required on the hot water side, because the water in the inner container, which is usually still heated, begins to flow out.
The picture shows the individual parts of the standardized upper part. A size 7 wrench is required to replace the valve disc. Check before screwing the upper part back on, ob der Fiberring, which seals the head piece to the valve seat, is still OK or whether it also needs to be replaced.
Renewal of the stuffing box
■ Mer wrenches, thorn or tweezers
■ Rubber ring, 8 mm inside diameter, 2 mm thickness
The stuffing box seal of the standardized upper part LAN 57, which is manufactured by the fittings factory in Leipzig, consists of a round ring, the seat of which is located in a cutout inside the head piece and which ensures an absolute seal with the polished shaft of the spindle. Experience has shown that replacement is only necessary after many years. The upper part is removed as previously described. Then the spindle is screwed out of the head piece. Tweezers are best for removing the old O-ring; the new one is “threaded” according to the picture and, if necessary, with a pencil (never with sharp objects!) pressed.
Glutos
Although electric water heaters work maintenance-free, is in some areas of our republic (especially in Erfurt, Magdeburg and Halle area) often after a relatively short period of operation, a heavy build-up of boiler scale can be detected on the devices, who expresses it, that instead of the intended 4 l/min only about 1 to 21 water through the reservoir.
Unlike cooking pots and whistling kettles, the housewife with chemical agents (acetic acid) can free himself from scale, the hot water storage tank may only be cleaned by a specialist. Since the contract workshops are usually not able, to carry out such maintenance work in the customer's home, the owner has to dismantle the memory and take it to the workshop. The individual operations: Pull out the plug from the Schuko socket, Loosen the union nuts on the connection to the mixer tap or. Sliding the rubber fittings up onto the accumulator sockets (this is constructed differently for the individual models), drain hot water and unhook the appliance.
During the time, in which the hot water tank is located in the authorized workshop, the mixer tap can still be used to draw off cold water; however, their upper connection pieces are previously fitted with metal discs (14 mm diameter) to close.
In order to avoid as far as possible scale deposits inside the device, the owner of a water heater should consider the following: It is advisable, in continuous operation, always set the temperature controller to half of the threshold arrow. This corresponds to a water temperature of 50 up to 60°C, which does not lead to any appreciable formation of scale. This results in a multiple win: Firstly, the cost of commissioning the device is reduced, since only up to about 50 °C needs to be heated and the heat radiated in this temperature range is lower than at 85°C, despite the best thermal insulation of the storage tank; secondly, the absence of scale build-up on the heating coil ensures maximum heat transfer, Thirdly, this means that the device is significantly longer maintenance-free; because heavy scale build-up destroys the radiator prematurely as a result of heat build-up.
There is another source of interference: If both when opening the hot water- and the cold water valve on the swivel arm, the same sparse jet of water exits, then that suggests it, that dirt particles from the pipeline have settled on the reducing nozzle of the mixer tap, which reduce the water flow rate. To remove these dirt particles, are after interrupting the current- and water supply, use a 19 mm spanner or an adjustable wrench to loosen the union nuts on the pipe connections to the mixer tap. When using a pipe wrench, place a rag between the jaws, so that the polished surface of the nuts is not damaged. The hot water from the storage tank then runs out of the right-hand pipe (caution, risk of scalding!).
Then the mixer tap is unscrewed from the wall socket. When cleaning the nozzle, its bore may 2 mm diameter cannot be expanded. Now the previously closed shut-off valve is opened a little, to flush any dirt particles that may still be present out of the line, and only after that you screw the mixer tap with the appropriate sealing material (hemp and varnish. oil paint) on again.
1 5-l-HeiBwasserspeicher, Type N511, with boiling water level. connection value: 2000 Watt (without boiling water level 1250 Watt)
2 10-l hot water tank
3 Boiling water heater KB 565 „Aquatherm” from VEB Metallverarbeitung Leipzig. connection value: 1600 Watt
4 Hot water tank EHN 80. connection value: 1000 Watt
5 If the 80 l storage tank is commissioned with discounted off-peak electricity, a separate meter is required.
6 Overflow principle of a hot water tank: When the hot water valve is opened, cold water penetrates the lower part of the copper tank and displaces the warm water inside, flowing through the overflow pipe to the swivel arm.
7 Unscrew the upper part with a size 14 key
8 Items of the standardized shell LAN 57:1 cross handle, 2 Fiber seal 20 Glutos 16,5 mm • 1mm, 3 Rubber valve disc seal 12,5 Glutos 4 mm-3 mm, 4 Head piece with spindle, 5 hex nut (7 mm) for valve disc seal
9 The stuffing box, a rubber ring 8 mm inner diameter and 2 mm thickness, serves to seal the head piece against the polished spindle shaft
10 Take out the old O-ring with the tweezers
11 Inserting the new O-ring