FAQ - Frequently Asked Questions
1. There is no description of a product?
If some parts of www.kotly.com.pl are not yet translated into English, please switch to the Polish or German version of the website.
2. Do you deliver to ... ?
We deliver throughout Europe and America—nearly worldwide. Delivery costs apply and depend on the total weight of the shipment.
3. May I pick up the boiler myself?
Yes, absolutely. We typically have 200–400 boilers in stock. Please email us a few days in advance so we can reserve your product.
4. Is placing an order binding?
No, not at all. Feel free to add your desired products to the shopping cart and place an order on
www.kotly.com.pl. This allows us to prepare a detailed offer including pricing, availability, and transport costs.
We’ll review and adjust your order, removing unnecessary items and adding essential accessories as needed. You’ll receive an edited version of the order by email.
5. What if I would like to customize a product (e.g., larger tank, longer pipe, additional options)?
If you'd like to make modifications, it's best to place a non-binding order and use the "Notes" field to describe your requests. This gives us enough information to respond quickly and accurately.
6. Should I pay immediately after placing an order?
No. Please wait for two confirmations from us. First, you’ll receive an automatic email acknowledging your order. Later, our export manager will send a second email with the correct transport cost and bank details. Only then should you make the payment.
7. Which boiler power do I need?
You must estimate the required boiler power based on the volume of your building and its insulation quality:
- Well-insulated building: 40 W/m³
- Non-insulated building: 48 W/m³
Example 1: Tenement house (300 m², 2.7 m high, no insulation)
Power = 300 × 2.7 × 48 = 38,880 W = 38 kW
Example 2: New house (150 m², 2.5 m high, very good insulation)
Power = 150 × 2.5 × 40 = 15,000 W = 15 kW
For non-metric units, convert:
1 m = 3.3 ft, 1 m² = 10.8 ft²
1000 W = 1 kW = 3413 BTU
BTU × 0.293 = W
Examples: 25 kW = 85,325 BTU; 50 kW = 170,650 BTU; 100 kW = 341,300 BTU
The above includes domestic hot water. Do not include unheated areas like basements or garages to avoid oversizing. Oversized boilers won’t operate efficiently within the recommended range of 65–85°C.
8. What options are available?
When viewing a boiler, scroll down to see available options. Some are free (e.g., left/right hopper), others are paid (e.g., extra grate). Also check for necessary accessories. Always select the appropriate options before adding the product to your cart.
9. Draught regulator or ventilator?
If you mainly burn coal or similar fuels, a ventilator with control is better. For wood as the primary fuel, choose a draught regulator. You can select this option on the boiler’s product page.
10. What is the difference between ATMOS S and GS boilers?
ATMOS S boilers have a standard ceramic plate in the combustion chamber. GS models include additional shaped ceramic inserts for optimized combustion.
11. Which tank do I need?
You may need:
- Accumulation tank: Made from black steel, used for heating water in your home (not for drinking).
- Domestic hot water tank (exchanger): Enamelled or stainless steel, used for household hot water like washing hands.
12. How to provide high efficiency of a boiler for a long time ?
The boiler should be regularly cleaned with a steel brush. Cleaning from flocks enables better warm gaining by the exchanger of the boiler. Appropriate brushes are available at kotly.com.pl. The diameter of the brush must be chosen properly. It should move inside the boiler without difficulties – it cannot be too big. The best solution is a 5% smaller brush than the cleaned space.
13. Upper or lower combustion ?
a) In case of boilers with upper combustion, exhaust gases are led directly from the combustion chamber up to the chimney. These boilers are usually high and their convectors are set horizontally. They are more popular than boilers with lower combustion because they are more universal. Generally, boilers with upper combustion can burn all solid fuels.
b) In case of boilers with lower combustion, exhaust gases are led from the combustion chamber first down and then up to the chimney. Convectors are long which results in high efficiency. Stronger chimney draught is for such a boiler required.
14. How can I set up a boiler with a feeder properly ?
Conveying the appropriate air to the boiler is a very important issue. The amount of air should be minimal, just for burning the fuel. Visually, it can be descripted as follows: remnants of glow should be at the edge of the retort furnace, but only ash should fall down out of it.
When the fuel is burnt properly, the flame is yellow and directs up and to the sides. White flame means too high draught. Red and smoky flame means that the draught is too weak. The coal or pellets should burn on the retort furnace, not inside. Burnt crater inside the retort furnace means too strong draught. This cools down the boiler and decreases its efficiency. Setting of the ventilator flap or its power must be adjusted to the outside temperature. The opening of the ventilator should be sometimes covered even at 80 – 90%. Lower the outside temperature, higher the natural chimney draught, hence the aeration should be limited. The combustion process must be controlled by the boiler steering, not by the chimney draught. The flame should be stable, it cannot blast like fire from a burner.
E.g. in the Eko–Tech boilers, the standard configuration of the feeding time to the blowing time is 1 to 3.
1st example: 10 sec. feeding with coal/30 sec. of blowing
2nd example: 15 sec. feeding with coal/45 sec. of blowing
In summer, the configuration can be at 1 to 4. E.g. 5 sec. of feeding/20 sec. of blowing.
Hysteresis should be set up at 1 centigrade (or at 2 centigrades if there is no other possibility).
Set up the time after which the feeder will work even if the set temperature has not decreased at 20 minutes.
Parameters of boiler work depend on many factors (fuel quality, installation, standard of the building, …), that is why most often the choice of the parameters should be empirical and individual.
15. How to carry a boiler with a hopper into a boiler room ?
The boiler can be disassembled into two parts. You can carry the boiler (exchanger) and the hopper separately. Then, just screw them together and seal up with high temperature resistant sealant.
