Buffer tank
A buffer tank adds usable water volume to a hydronic heating or cooling loop. Its job is system stability, thermal mass, minimum runtime, and smoother operation.
HYDRONIC STORAGE, BUILT TO LAST
Stainless Steel Buffer Tanks
Stainless steel buffer tanks for heat pumps, boilers, chilled water, and hydronic heating and cooling systems. Designed to improve system stability, reduce short cycling, and support efficient performance.
Heat pumps | Boiler systems | Hydronic storage
What is a stainless steel buffer tank?
A stainless steel buffer tank is an insulated hydronic storage tank that adds water volume and thermal mass to a heating or cooling loop. In a heat pump, boiler, or chilled water system, the tank helps stabilize supply temperature, improve minimum system volume, and reduce short cycling.
Unlike a general storage tank, a hydronic buffer tank is selected as part of the mechanical system. It supports equipment runtime, flow stability, zoning behavior, and comfort in systems with radiant floors, fan coils, air handlers, boilers, or air-to-water heat pumps.
APOLLO stainless buffer tanks for hydronic systems
APOLLO stainless steel buffer tanks are built for MBTEK hydronic systems, including air-to-water heat pumps, boiler systems, chilled water loops, radiant heating, fan coils, commercial air handlers, and mechanical-room packages.
This collection targets installed HVAC and hydronic applications. Use it when the project needs buffer volume for heating or cooling performance, not a generic water storage vessel.
Choosing the right APOLLO buffer tank
Start with system type, heat source output, load profile, available space, and required hydronic volume. Then confirm tank size, connection layout, coil configuration, and installation details on the product page.
APOLLO BF30
Compact 30 gallon stainless buffer tank for smaller hydronic systems, heat pump loops, and mechanical rooms that need added system volume.
View productAPOLLO BF80
80 gallon stainless buffer tank for larger residential and light commercial heat pump, boiler, or hydronic heating and cooling systems.
View productAPOLLO BF175/BF250
Large stainless buffer tanks for commercial hydronic systems, boilers, biomass systems, chilled water loops, and projects needing 0-coil or 2-coil configurations.
View productBuffer tank vs storage tank vs expansion tank
Storage tank
A storage tank is a broad category. For MBTEK systems, the relevant storage use is hydronic buffer volume that supports heat pumps, boilers, chilled water, radiant, fan coil, or air handler equipment.
Expansion tank
An expansion tank absorbs fluid expansion and helps manage system pressure. It does not replace a buffer tank because it does not provide the same thermal storage volume.
Why buffer tanks matter for heat pumps, boilers, and chilled water
Modern hydronic systems often have small zones, variable loads, and equipment that performs better with stable flow and longer runtime. A buffer tank can help the heat source avoid rapid on/off cycling when the active load is smaller than the equipment output.
In air-to-water heat pump systems, buffer volume can support defrost behavior, small-zone operation, radiant floor loops, and fan coil loads. In boiler and chilled water systems, it can help stabilize temperature swings and improve operating consistency.
Sizing and installation basics
Buffer tank sizing depends on the complete hydronic design. A contractor should confirm heat source output, minimum runtime, total system volume, flow rate, temperature differential, zoning, piping strategy, heating and cooling loads, and available access space.
System volume
Confirm whether the heat pump, boiler, or chiller needs additional water volume for stable operation.
Load profile
Small zones, low-load periods, and variable heating or cooling demand can increase the need for buffer capacity.
Connections
Review port sizes, sensor wells, drain access, relief components, and piping layout before selecting a model.
Coil options
For larger BF tanks, confirm whether the project needs a no-coil buffer tank or a 2-coil configuration.
Maintenance basics for stainless steel buffer tanks
A stainless steel buffer tank is a durable hydronic component, but the complete system still needs routine checks. Follow the product manual, local code, and the maintenance schedule for the heat source, pumps, controls, valves, and fluid treatment.
Connections
Inspect hydronic connections, plugs, drain points, and nearby piping for moisture or signs of maintenance issues.
Safety components
Verify relief valves, gauges, air removal, and related components according to the system design and manual.
Insulation
Check insulation, jacket condition, and condensation control in chilled water or cooling applications.
Fluid quality
Maintain water or glycol quality so pumps, coils, heat exchangers, and stainless tank surfaces stay protected.
Stainless Buffer Tank FAQ
Stainless Steel Buffer Tanks - Frequently Asked Questions
Direct answers about hydronic buffer tanks, heat pump and boiler compatibility, chilled water systems, sizing, installation, and maintenance.
What is a stainless steel buffer tank?
A stainless steel buffer tank is an insulated hydronic tank that adds water volume and thermal mass to a heating or cooling loop. It helps heat pumps, boilers, and chilled water systems run with more stable temperatures and fewer short cycles.
What does a buffer tank do in a hydronic system?
A buffer tank increases system volume so the heat source has more water to heat or cool before cycling off. This can help stabilize flow, reduce temperature swings, support small zones, and improve comfort in hydronic heating and cooling systems.
Do heat pumps need buffer tanks?
Some air-to-water heat pump systems need a buffer tank, especially when the distribution side has small zones, low water volume, variable loads, or minimum flow requirements. The final decision depends on the heat pump, load, controls, and piping design.
Do boilers need buffer tanks?
Boilers may need a buffer tank when the system load is often lower than boiler output, when zoning creates short cycles, or when the design needs additional hydronic volume. A contractor should match tank capacity to the boiler and system behavior.
What is the difference between a buffer tank and a storage tank?
A storage tank is a broad term for holding fluid. A buffer tank is a specific hydronic storage tank that adds thermal mass and water volume to a heating or cooling system. In MBTEK systems, buffer tanks are selected for HVAC performance and equipment stability.
What is the difference between a buffer tank and an expansion tank?
A buffer tank provides hydronic volume and thermal storage. An expansion tank absorbs fluid expansion and helps protect the system as temperature changes. Both can appear in the same mechanical room, but they solve different problems.
How do I size a buffer tank?
Size a buffer tank from heat source output, minimum runtime, system volume, flow rate, temperature differential, zone behavior, and heating or cooling load. There is no single universal size for every hydronic system, so sizing should be confirmed by the project designer or contractor.
What maintenance does a stainless steel buffer tank need?
Maintenance includes checking hydronic connections, insulation, safety components, air removal, drain points, sensor wells, and water or glycol quality. The tank should be maintained as part of the complete hydronic heating or cooling system.
