The UK Cylinders FlowCyl Slimline 200L Heat Pump Cylinder (FCHPS3200) is a space-saving unvented hot water cylinder designed for properties with restricted cupboard or airing cupboard width. At just 475mm in diameter, it delivers the same 150L–600L FlowCyl performance in a narrower footprint, making it ideal for retrofits where a standard 545mm diameter cylinder won't fit.
Despite the slimmer profile, the cylinder retains UK Cylinders' high flow, high gain, full bore heat exchanger coil with a 2.08m² surface area, engineered for efficient heat transfer from air source and ground source heat pumps, and is supplied as a complete unvented kit for Part G compliant installation.
200L
Nominal Capacity
475mm
Slimline Diameter
2.08m²
Coil Surface Area
1.80 kWh/24h
Standing Heat Loss
Band C
ErP Efficiency
25 Yrs
Cylinder Warranty
Good to Know
The FlowCyl range is WRAS approved and manufactured under ISO 9001 certified quality management, and is fully compliant with Part G (unvented hot water) and Part L (energy efficiency) of UK Building Regulations.
Duplex Stainless Steel Cylinder
Manufactured from high-grade 1mm thick Duplex Stainless Steel for long service life and excellent corrosion resistance.
Slimline 475mm Diameter
475mm diameter body — significantly narrower than the standard 545mm FlowCyl range — designed to fit tighter airing cupboards and retrofit spaces.
High-Gain Heat Pump Coil
Fitted with UK Cylinders' in-house designed, high flow, full bore heat exchanger coil, engineered for rapid heat transfer from the low-temperature output of air and ground source heat pumps.
Universally Compatible
Designed to work with any air source or ground source heat pump, making it a flexible choice regardless of which heat pump brand is specified.
50mm CFC/HCFC-Free Insulation
Wrapped in 50mm 100% CFC and HCFC-free polyurethane foam insulation with a 100% recyclable silver casing, keeping standing heat loss low and Part L compliance straightforward.
Complete Unvented Kit Included
Supplied as a full system unvented kit, with all safety controls required to meet UK Building Regulations Part G included as standard.
25-Year Cylinder Warranty
Backed by a manufacturer's 25-year cylinder warranty and 2-year parts warranty (terms and conditions apply), reflecting UK Cylinders' confidence in build quality.
Technical Specification
General
Product Code
FCHPS3200
Cylinder Type
Unvented, indirect heat pump cylinder — slimline
Nominal Capacity
200 litres
Mounting Orientation
Vertical
Weight (Empty)
48 kg
Weight (Full)
248 kg
Height
1941 mm
Diameter
475 mm (slimline)
Hydraulic & Performance
Primary Coil Surface Area
2.08 m²
Coil Rating
24.67 kW
Hot & Cold Connections
22 mm
Sensor Probe Pocket
12 mm
Secondary Return
Not included as standard
Standing Heat Loss
1.80 kWh/24h (75 Watts)
ErP Efficiency Band
C
Construction
Cylinder Material
Duplex Stainless Steel, 1mm thick
Insulation
50mm CFC/HCFC-free polyurethane foam
Outer Casing
100% recyclable silver casing
Compliance & Warranty
Approvals
WRAS approved; ISO 9001 certified manufacture
Building Regulations
Part G and Part L compliant
Cylinder Warranty
25 years (manufacturer backed)
Parts Warranty
2 years (terms and conditions apply)
Please Note
This slimline model has a taller profile (1941mm) than the equivalent standard-diameter cylinder to compensate for the reduced 475mm diameter. Check available cupboard height as well as width before ordering.
What's Included
3kW Immersion Heater
Long-life Incoloy element supplied as standard, upgradeable to Titanium or 6kW on request.
T&P Relief Valve
Temperature and pressure relief valve for safe overpressure/overtemperature protection.
Tundish
Visible air-gap tundish for the discharge pipework, as required by Part G.
Cold Water Inlet Control Set
3 bar inlet control set for regulating incoming mains pressure.
2-Port Zone Valve
28mm zone valve for controlling the heat pump primary circuit.
Expansion Vessel & Bracket
External potable expansion vessel with wall-mounting bracket.
High Limit Thermostat
Safety cut-out thermostat to prevent excessive water temperatures.
Please Note
A 12mm sensor probe pocket is included for connection to your heat pump's controls. Confirm your heat pump's flow/return connection sizes and controller compatibility with your installer before ordering.
Important Safety Information
This is an unvented hot water cylinder and must be installed and commissioned by a competent, G3-qualified installer in accordance with Building Regulations Part G and the manufacturer's installation instructions.
Frequently Asked Questions
What heat pumps is the FlowCyl Slimline 200L compatible with?
This cylinder is universally compatible with any air source or ground source heat pump, thanks to its high-gain full bore coil design and standard 12mm sensor probe pocket.
What's included with the cylinder?
Each unit is supplied as a complete unvented kit, including a 3kW immersion heater, T&P relief valve, tundish, cold water inlet control set, 2-port zone valve, external expansion vessel, and high limit thermostat — everything needed for a Part G compliant installation.
What is the cylinder's standing heat loss and ErP rating?
The 200L model has a standing heat loss of 1.80 kWh/24h and carries an ErP energy efficiency band C, helped by its 50mm CFC/HCFC-free polyurethane insulation.
What warranty does the cylinder carry?
UK Cylinders backs the FlowCyl range with a 25-year manufacturer's warranty on the cylinder vessel and a 2-year warranty on parts (terms and conditions apply).
Does the cylinder need to be installed by a qualified installer?
Yes. As an unvented cylinder, installation must be carried out by a competent, G3-qualified installer to comply with Building Regulations Part G.
BTU & WATT Calculator
Room Dimensions
Room Type
Living Room
Bedroom
Kitchen
Bathroom
Conservatory
Hallway
Glazing Type
Single Glazed
Double Glazed
Triple Glazed
External Walls
0 Wall
1 Wall
2 Walls
3 Walls
4 Walls
Insulation Level
Poor
Average
Good (New Build)
Required Heating
0
Watts
0
BTUs
Documentation
Do you have a question about this product?
One of our expert advisors will be happy to help you!
