Retra-6M 21 kW boiler

Retra-6M 21 kW boiler

The Retra-6M boiler is a solid fuel, shaft-type hot water boiler designed for domestic use and operates on the bottom combustion principle. The boiler walls and flue gas ducts are water-cooled and made of high-quality boiler steel. The grate is cast iron ( the Retra 6M Comfort model has movable grates), and ash removal is manual.

Optionally, the boilers are suitable for mounting a fan or smoke exhauster and a control unit (controller), which monitors the combustion process and the operation of the central heating pump.

The boilers are designed for operation in central water heating systems with forced (closed pressure heating system) or natural (open heating system) circulation of the coolant for heating and hot water supply of residential buildings, summer cottages, industrial and warehouse premises, retail facilities, social and administrative buildings.

Advantages of a shaft boiler compared to classic boilers (type 5M):

• A much larger firebox volume and, accordingly, a much longer operating time on one load (up to 8 hours)
  
• Low cost and simple design.
• Possibility to burn various types of fuel (wood, briquettes, peat briquettes, coal, wood waste).
• Movable cast iron grates for convenient fuel stirring (Retra 6M Comfort).

1. loading hatch
2. steel heat exchanger
3. thermometer
4. combustion chamber
5. lower hatch
6. cast iron grates
7. ash box
8. air duct
9. vertical partitions
10. nozzle plate
11. chimney
12. straight pull handle
13. damper handle
14. cleaning hatch with a peephole
15. thermal insulation

Design and operating principle

The steel heat exchanger consists of two parts: the combustion chamber in the front and the convection channels in the rear. The entire heat exchanger is cooled by water, forming a "water jacket." Water from the heating system spreads through the internal cavities of the heat exchanger and, through its metal walls, absorbs heat from the burning fuel (via contact and radiation) and the combustion gases (via convection). Combustion occurs on movable or fixed cast-iron grates, with an ash pan located beneath the grates. A hatch is located on the upper front side of the boiler, while an ash removal and stoking hatch and a thermometer are located on the front. The rear side houses a flue with a damper, a direct draft handle, and inlet and outlet pipes. A layer of thermal insulation is located under the decorative casing. The grate stoking handle is located on the left side of the Retra 6M Comfort model.

Additional options (not included in standard package):

• Ten
  
• Control unit
• Smoke exhauster
• Fan
• Mechanical traction control