What Is a Hydro (Boiler) Pellet Stove and How Does It Work?

Short answer: a hydro (boiler, water-jacketed) pellet stove heats the central-heating water rather than mainly the room air; the water jacket in the body connects to the radiator system and a circulation pump moves the water. The three models on our site are rated 14 kW and 22 kW: the manual Hidro H 14, the glassless automatic boiler Hidro D 22 and the glazed automatic Hidro A 22.

Current prices and all models: Hydro pellet stove prices →

Which boiler models are there, and what is known?

* manufacturer data sheet: the value was read from the data sheet or drawing image on the manufacturer's product page.

The same models in a table generated from the product records (values and prices always match the product page):

How does it work?

The water jacket around the firebox transfers the fire's heat to the heating water. The water flows out to the radiators, cools and returns through the return line. The system has a circulation pump, an expansion tank and a safety valve; connecting them is a job for a qualified heating engineer. In the automatic models (Hidro A and D) an auger feeds pellets from the hopper and an electronic board controls ignition and water temperature, so they do not run without electricity. In the manual Hidro H 14, feeding and combustion are adjusted by hand.

Hidro A, D or H?

Hidro A 22 is glazed and shows the flame; it can stand in a living area. Hidro D 22 has the same output in a closed boiler body, meant for a boiler room or pantry; the difference is 1,300 TL. Hidro H 14 is manual; it suits homes that will run fewer radiators and do not want the power dependence of automatic boilers. Which model covers your radiator count can only be said with a heat-loss calculation and the manufacturer's output-to-water figure, so we give no estimate of radiator count.

What does it depend on?

• Heat-loss calculation: In a radiator system the floor-area rule alone is not enough; the total radiator output and the home's heat loss must be calculated by the heating engineer. The TS 825 climate zone is an input to that calculation. For a rough starting value the stove sizing calculator gives the home's kW need; the heating engineer has the final word.
• Existing system: Open or sealed expansion, pipe size and pump status decide the connection.
• Electricity: The automatic models stop in a power cut, and so does the pump: what happens in a power cut.
• Flue: A sealed, condensation-resistant 80 mm line for the automatics; 130 mm for the manual H 14: flue rules.
• Pellet stock: A stove running several radiators burns far more pellets than a single-room stove; dry storage and certified pellets matter: ENplus A1 pellets.

If your heating engineer has questions before ordering, send them to us and we will get the manufacturer's answer.

Price note: Figures are the VAT-inclusive prices shown on our site on 20 October 2026 and may change. The current price appears on the product page and in the cards below. Products are supplied by the manufacturer to order; delivery and shipping details are confirmed before ordering.

Safety note

No stove is "smokeless"; pellets, wood and coal all produce smoke and carbon monoxide as they burn. A flue of the right diameter that draws properly and leak-tight pipe joints are therefore essential, and in water systems the safety valve and expansion tank must not be skipped. Use a carbon monoxide detector at home; with headache, dizziness or nausea, air the room, get outside and call 112: stove gas symptoms and carbon monoxide detectors.

Frequently asked questions

Is the Hidro H 14 manual or automatic?

Manual: feeding and combustion are adjusted by hand, and the stove itself needs no electricity. Current prices are on the hydro pellet stove page.

How many radiators can a hydro pellet stove run?

That depends on the output to water and the radiators' output. Without that figure we give no estimate of radiator count.

Does a hydro pellet stove work without electricity?

Hidro A and D do not. The manual Hidro H 14 itself needs no electricity, but a circulation pump in the system does.

Can it be connected to an existing radiator system?

Usually yes, but the connection and safety components must be designed by a qualified heating engineer.

What is the difference between Hidro A and Hidro D?

Both are 22 kW and automatic. A is glazed and meant for a living area, D is a boiler without glass; the price difference is 1,300 TL.

Sources: manufacturer pages Hidro A 22, Hidro D 22, Hidro H 14 (including the technical drawing); how pellet stoves work, U.S. EPA Burn Wise, "Pellet Stoves"; TS 825 degree-day zones: METU open archive, study.