Absorbs consumption peaks
Morning shower time at a hotel, shift changes at a factory. Instantaneous demand can far exceed production capacity. Stored water closes that gap, so you don't have to oversize the equipment for the peak.
Product group 02
Pressure Vessels & Calorifiers
If the exchanger is the equipment that produces hot water, the pressure vessel is what holds it. It absorbs instantaneous consumption peaks and stops the boiler from short-cycling.
Volume100 – 10,000 liters
Design pressure6 / 10 / 16 bar
Operating temperature≤ 110 °C
Body materialS235 / AISI 304 – 316
Single-coil calorifier · indirectly heated hot water storage
Why it's needed
What does a pressure vessel do in the installation?
No matter how accurately the heating capacity is sized, consumption is sudden and irregular. The pressure vessel absorbs that fluctuation and eases the load on the system.
Extends the boiler's operating life
Without storage, the boiler fires up for every small demand. Frequent short-cycling wears down the burner, ignition group and body. A tank extends run time and reduces the number of firing cycles.
Downsizes capacity, lowers investment
A correctly sized buffer tank noticeably reduces the boiler and exchanger capacity required. The difference in upfront investment often covers the cost of the tank itself.
Combines alternative heat sources
Bring together a solar collector, heat pump and boiler in the same volume. Coil and multi-coil types are made for exactly this; sources work in layers rather than in sequence.
Dampens pressure fluctuation
Pump start-stops and valve closures in process lines produce pressure surges. A correctly sized vessel absorbs that surge, protecting pipework and fittings.
Requires certified manufacturing
A pressure vessel is a product whose design and welding are subject to inspection. It shouldn't be accepted onto a site without CE marking, PED compliance and a manufacturing file. The vessels we supply come fully documented.
Types
Which type, for which job?
The distinction isn't about volume — it's about what's inside and how the water is heated.
Single/multi-coil calorifier
The boiler circuit runs through a coil, heating the domestic water inside the tank. The standard for residential and hotel hot-water lines.
- Single or twin coil
- Enamel or stainless interior surface
- Requires anode rod maintenance
Buffer tank
No coil; heating is done by an external exchanger, the tank only stores. More flexible at large capacities.
- Exchanger capacity selected independently
- Layered storage possible
- Requires a circulation pump
Process and air vessel
Volume, pressure and connections tailored to the production line. Stainless or coated body, suited to food and chemical lines.
- Custom-built to dimension
- High pressure classes
- Supplied with material certification
Selection criteria
What data determines the right vessel?
Volume alone isn't enough. Once the eight items below are clear, the selection narrows to a single model.
ParameterWhy it mattersWhat we need from you
Storage volume
Calculated from instantaneous consumption, peak duration and recovery time. Too much volume brings heat loss; too little brings loss of comfort.
Liters
Heating capacity
Determines how quickly the tank reheats. In the coil type this is the coil surface area; in a buffer tank it's the external exchanger's capacity.
kW and heat-up time
Design and operating pressure
Based on building static pressure and mains pressure. Directly affects body wall thickness in high-rise buildings.
6 / 10 / 16 bar
Operating temperature
60–65 °C is typical for domestic hot water. Higher temperatures in process applications change insulation and material selection.
°C
Body and interior surface material
Enamel-coated steel is economical; stainless requires no maintenance. Selection becomes critical in water with high chloride content.
Enamel / AISI 304 / 316
Coil count and surface area
Based on how many heat sources will be connected. A solar + boiler combination calls for a twin coil.
Count and m²
Insulation class
Determines standby loss. In tanks kept hot continuously, the annual energy difference adds up significantly.
Thickness and material
Connection sizes and layout
Flange/thread sizes, leg type, and entry clearance into the boiler room. A tank that doesn't fit through the doorway is a common problem.
DN sizes + doorway width
This much is enough for a quote
You don't need all of it. We'll work out anything missing together with you.
Create a quote request- Building type and number of users/beds
- Instantaneous hot water consumption or peak flow rate
- Desired domestic hot water temperature
- Heat source (boiler, solar, heat pump)
- Number of building floors or static pressure
- Boiler room entrance doorway size
FAQ
Questions from the field
The four questions we hear most often at the quote stage.
How many liters of tank should I buy?
What matters isn't the number of users so much as consumption during the peak hour. A hotel's morning shower load, squeezed into two hours, requires a different volume than a dorm with the same bed count. We calculate this together by taking your consumption profile and recovery time into account; a tank chosen by guesswork means either wasted money or cold water in the morning.
Enamel or stainless?
Enamel-coated steel is more economical but requires periodic checks of the anode rod; if neglected, the body becomes vulnerable to corrosion. Stainless removes that maintenance need, at a higher upfront cost. If the water's chloride content is high, even stainless may need 316 grade — 304 may not be enough.
Is there a legal requirement for pressure vessels?
Yes. Pressure equipment is assessed under CE marking and the PED (2014/68/EU); it falls into different modules depending on volume and pressure. There's also a periodic inspection obligation once in service. The vessels we supply come with a manufacturing file and declaration of conformity.
What if it doesn't fit through the existing boiler room?
There are two paths: split the same total volume across several smaller tanks, or choose a narrow-bodied tall type. Since we ask about the doorway clearance from the start, you won't run into a tank that can't be delivered into place.
Next step
Let's work out the volume together
Share your consumption profile, and let's work out the right volume and heating capacity together.