Boiler installation
GENERAL CONDITIONS FOR THE PROPER FUNCTION AND HIGH EFFICIENCY OF ATMOS BOILERS.
- Boiler installation may be provided only by professional installation firms trained by the manufacturer.
- The boiler must be installed in a dry and well ventilated space - boiler room.
- When connecting the boiler to the system it is always necessary to install the Laddomat 21 or TV 60°C thermoregulation valve downstream from the boiler together with a pump, ball valve, floating non-return flap valve and filter, to ensure that water returning to the boiler never drops below 65°C - according to the standard ČSN 070240/93. (The amount of condensing tars and acids decreases with the increasing temperature of water returning to the boiler = increased boiler durability). We advise using Laddomat 21 only up to the output of 50kW inclusive.
- The pump in the boiler circuit must always be switched by an independent thermostat when the temperature reaches 70 - 80°C. In the case of a boiler connected without accumulation tanks, the pump in the circuit of the heated object may only run when the pump in the boiler circuit is running (simultaneously). The reason is to avoid the undercooling of the boiler through the back flap in the boiler circuit or Laddomat 21.
- In every boiler mode the temperature of water exiting the boiler must be 80 - 90°C.
- If the boiler is operated permanently at less than 40 % of nominal output or if it is used for heating water during the summer, it is necessary to heat it daily heat to maintain boiler durability. The boiler may not be operated permanently in the minimum output mode, when tars or acids may originate.
- The boiler must be protected against overheating in case of electric power failure, because it exhibits a certain extent of inertia.
Variants of solutions of boiler security against overheating
- anti-overheating circuit installed with a valve TS 130 ¾ 90°C) or WATTS STS 20
- reserve source of electric energy (battery) for the pump (see the price list; we do not connect boilers to this source)
- one of the branches in the system connected to spontaneous water circulation with several
- boiler connected with an aftercooling tank and an inverse zone valve
ATTENTION - ALL BOILERS MADE IN 2003 AND BEFORE ARE EQUIPPED WITH A COOLING CIRCUIT.
RECOMMENDED INSTALLATIONS - CLASSIFIED IN ORDER ACCORDING TO BEST ADVANTAGES
- The most recommended connection of the boiler with a Laddomat 21 and accumulation tanks.
- Recommended connection of the Laddomat 21
- Recommended connection of the boiler with an ESBE thermoregulation valve.
- Recommended connection of the boiler with an expansion vessel.
(Note to the diagrams: In the case of pump operation, a return valve is closed by over-pressure on the pump output; in the case of pump switch-off, the valve is fully opened.))
Other 42 recommended configuration of installation
- The chimney draught must reach specified values (21 - 35 Pa depending on boiler type).
A small draught reduces boiler durability - the boiler is more prone to tar deposition, becomes clogged and smokes when adding fuel.
Solution: line the chimney or install a special adapter or exhaust fan on the chimney.
A large draught increases fuel consumption (increased chimney loss - lower boiler efficiency).
Solution: install a throttle valve in the flue duct between the boiler and chimney.
- The boilers charging area and rear collection duct must be cleaned regularly of ash and dust.
WARNING - The chimney must be well sealed and insulated, to avoid condensation of water vapour and tar in the chimney during reduced boiler output.
Recommendations from ATMOS
Most of the conditions above are met by installing the boiler together with accumulating vessels. Therefore, we strongly recommend it.
Failure to comply with these instructions shall lead to the termination of the guarantee and reduces boiler durability.

- Laddomat 21
HEAT ACCUMULATION
Installation of the boiler together with accumulating vessels result in a number of advantages:
- lower fuel consumption (20 - 30%), the boiler operates at full power output and maximum efficiency, until the fuel has burned out
- long life-span of boiler and chimney - production of tar and acids are minimized
- combination with other ways of heating are possible - e.g. utilizing electricity for heat accumulation
- designed for a combination of heating elements (radiators) with floor heating
- comfortable heating and a perfect burning out of the fuel
- more ecological heating
- 3-year guarantee on the boiler drum
We recommend installation of the boiler together with accumulating vessels as the main installation alternative.
If you cannot provide for the recommended accumulation tank volume, connect the boiler with at least one 500-1000 l expansion vessel. The heating system must be installed by a qualified company according to ČSN 060830. If you select an accumulation tank with a large volume, you also have to select a boiler with the corresponding output, so that it can charge the tanks in a reasonable time.
BOILER INSTALLATION WITH ACCUMULATING VESSELS AND LADDOMAT 21 - CONNECTION GRAPH
| Tubing diameter in an installation with accumulating vessels | ||||
|---|---|---|---|---|
| Type and boiler power output | part A | part B | ||
| Cu | Steel | Cu | Steel | |
| DC 18S, C 18S, DC 20GS | 28x1 | 25 (1") | 28x1 | 25 (1") |
| DC 22S, DC 25S, DC 25GS, C 20S, DC 22SX | 28x1 | 25 (1") | 28x1 | 25 (1") |
| DC 32S, DC 32GS, C 30S, DC 30SX | 35x1,5 | 32 (5/4") | 28x1 | 25 (1") |
| DC 40GS, C 40S, DC 40SE, DC40SX | 35x1,5 | 32 (5/4") | 28x1 | 25 (1") |
| DC 50S, DC50SE | 42x1,5 | 40 (6/4") | 35x1,5 | 32 (5/4") |
The Laddomat 21 is designed for boilers up to 75 kW, however, we
recommend its use to a maximum of 50 kW.
We recommend for boilers with output of over 50 kW to be equipped with the biggest thermoregulation valve ESBE and a strong pump or an electrically controlled servo-operated three-way valve maintaining the minimum temperature of return water between 65 - 75°C. The connection of a boiler with accumulation vessels can be performed using an open or closed expansion vessel.
System operation with accumulators
After firing the boiler, during operation at maximum output (2 to 4 loads), we heat the accumulation tanks to the requested temperature of 90 - 100°C. Then we let the boiler burn out. After that, we take heat from the reservoir via a three-way valve, for a time period corresponding to the size of the reservoir and outside temperature. In the heating period (provided that the minimum accumulator capacities are observed), this can amount to 1 to 3 days. In case it is not possible to use accumulation, we recommend for at least one 500 to 1000 l tank to be installed for balancing the starts and finishes of the boiler.
Vessel insulation
Accumulation tanks are commonly supplied without insulation. A suitable solution is joint insulation of the specified number of tanks (of required volume) with mineral wool in a frame made of plasterboard, or additional filling with poured insulation. The recommended thickness of insulation (mineral wool) is 120 mm. Another possible option is to purchase tanks already insulated with mineral wool in an imitation-leather casing, also supplied by our company.
Hot service water heating
We can use the combined boiler or an accumulation tank with a copper flow heater to heat up hot service water (see the price list).
Laddomat 21

- Laddomat 21
Its construction substitutes a classic connection of several independent parts. It is comprised of a cast-iron body, thermoregulation valve, pump, non-return flap valve with no spring, ball valves and thermometers. When the water in the boiler reaches a temperature of 78 °C the thermoregulation valve opens the supply from the tank. A connection with the Laddomat 21 is much simpler, therefore we highly recommend it. The Laddomat 21 fitting is supplied with a thermo-cartridge for 72 °C, which is designed for boilers over 32 kW.
| OPERATING DATA | |
|---|---|
| Max. operating pressure | 0,25 MPa |
| Construction pressure | 0,25 MPa |
| Testing pressure | 0,33 MPa |
| Max. operating temperature | 100 °C |
| VESSEL TYPE | VOLUME (l) | DIAMETER (mm) | HEIGHT (mm) |
|---|---|---|---|
| AN 500 | 500 | 600 | 1901/1940 |
| AN 750 | 750 | 750/790 | 1925/1752 |
| AN 1000 | 1000 | 850/790 | 2011/2202 |
The tanks are supplied without insulation or with insulation in leatherette housing.
| MINIMUM ACCUMULATING VESSEL VOLUME | ||||||||
|---|---|---|---|---|---|---|---|---|
| Type | DC 18S | DC 22S | DC 25/25GS | DC 32/32GS | DC 40GS/SX | DC 50S | DC 70/75SE | DC 100 |
| Power output / kW | 20 | 22 | 25 | 35/32 | 40 | 49 | 70 | 99 |
| Volume / l | 1000 1500 |
1500 2000 |
1500 2000 |
2000 2500 |
2500 3000 |
3000 4000 |
4000 5000 |
5000 6000 |
We recommend to always select a greater volume of the accumulation tank out of the given extent.
| MINIMUM ACCUMULATING VESSEL VOLUME | |||||
|---|---|---|---|---|---|
| Type | C 18S | C 20S | C 30S | C 40S | C 50S |
| Power output / kW | 20 | 25 | 32 | 40 | 48 |
| Volume / l | 1 000 - 1 500 | 1 500 - 2 000 | 2 000 - 2 500 | 2 500 - 3 000 | 3 000 - 4 000 |
Heating systems with accumulating vessels, is the best setup with boilers for solid fuels.


