HG Series Cylinders – Designed by Heat Geek

Introducing the HG Series
Designed by Heat Geek | Made by Newark Cylinders

Bespoke hot water cylinder manufacturer, Newark Cylinders, have launched the HG series – a range of ultra-high efficiency cylinders designed by leading heating experts, Heat Geek.

The HG Series has been designed to be the most efficient hot water cylinder available in the UK. This is being continuously and independently measured by the live performance data that is available at heatpumpmonitor.org.

All HG Series Models include a 6.0m² coil (except the HG150A which has a 4.0m² coil, due to insufficient space) as well as other features which are specifically designed to optimise stratification.

They are also designed to maximise the effect of what Heat Geek calls “the heat source saturation point”. This means that heat pumps will heat the hot water with a much lower flow temperature, rapidly increasing their efficiency. If used with a gas boiler this will mean the boiler will either completely condense in hot water, (increasing gas efficiency by over 10%, if controlled as Heat Geek suggest), or give the fastest recovery time currently available on the market.

The HG Series A models are available from 150L to 450L. The HG Series B models are designed for installation spaces with restricted height and are available in two sizes; 230L and 300L. Furthermore, all HG Series models include a steel mounting plate, and 90° ergonomic Carrying Handles.

View the HG Series Price Guide

We have created an online ordering form to streamline the ordering process for you.


  • 6.0m² Heat Pump Coil with reverse return configuration
  • 35mm Diffuser Tube on 1″ F BSP Cold Inlet to increase stratification
  • 320x230mm steel plate for mounting controls and/or product literature.
  • Carrying Handles spaced at an ergonomic 90° apart (two at high level, and two at low level).
  • Tall and slim construction to maximise stratification.

Additional Features

  • 1″ F (Female) BSP Hot Outlet
  • ¾” F BSP for TPRV (Temperature & Pressure Relief Valve)
  • 2x ½” F BSP with fitted 10mm Pocket
  • 1¾” F BSP Immersion Heater Boss (positioned halfway up)
  • 22mm Compression Secondary Return
  • ½” F BSP Drain Connection

General Specification

Pressurisation Description:Unvented
Heat input Description:Single coil (HP)
Manufacturing Material:1.0mm Duplex SS for 375mm & 450mm units / 1.5mm 316L SS for 500mm diameter units
Product Type:Cylinder
Normal Working Pressure:3.0 Bar
Maximum Working Pressure:6.0 Bar
Test Pressure:9.0 Bar
Cold Mains Inlet:1″F BSP (with internal 35mm diffuser tube – no side holes, open-ended, not flared)
Hot Mains Outlet:1″F BSP
Heat Input Coil:Surface area varies – See Models Specification.

Bottom lap is stretched down into base.
Controls:2x ½”F BSP Connections With Fitted 10mm Dry Pockets
Secondary Return Connection:22mm compression
TPRV Connection:¾”F BSP
Drain Valve Connection: ½”F BSP
Immersion Heater Boss(es): 1x 1¾”F BSP (positioned at halfway up)
Carrying Handles:In case body – 2 at high level, 2 at low level, each pair spaced approx. 90° apart (centred opposite the coil connections for balance)
Control Mounting Plate (to accommodate
controls/ literature):
320 x 230mm (portrait orientation) (top edge positioned 50mm below case lid)
Finish:Metallic silver case
Labels:HG-branded data label, HG logo sticker, JTE sticker. Supplied Loose
Components:Thermostat Pockets x2
½” 5 bar Expansion Relief Valve (for 250L, 300L, 350L & 400L Models)
¾” 7 bar Temperature & Pressure Relief Valve
22 x 28mm Tundish
1” 3 bar Pressure Reducing Valve & 1” Check Valve (for 250L, 300L, 350L & 400L Models)
½” Drain Valve
3kW Immersion Heater
22mm Combined 3 bar PRV, Check Valve & ½” 6 bar ERV (for 150L and 200L models)
A suitably sized Expansion Vessel & Hose

Price Guide

For the HG Series, we offer discounts based on the purchaser’s level of training and on minimum order quantities.

The taller A Models should be used wherever possible. If, however, the installation space has a height restriction, the shorter B Model variants are also available.

Heat Geek Verified and Elite Installers are eligible for a significant discount.
Please Note: You will need to be identifiable as either a Verified or Elite Heat Geek Installer on the Heat Geek map.
Non-Heat Geek Verified installers/suppliers are also eligible for a discount, so please get in touch with us.


Purchase the HG Series Cylinder

If you are interested in purchasing a HG Series Cylinder, please contact our Sales team.

[email protected] | tel: 01636 678437 | WhatsApp: +447868841262

About Heat Geek

Heat Geek was created to give expert advice on all aspects of the heating industry to both end users and industry professionals.

Heat Geek is the one stop to find out everything from how to bleed a radiator to selecting the right boiler, we don’t have any bias and value the facts above everything else.

Heat Geek‘s BPEC-certified courses allow installers and engineers to increase their knowledge of existing heating installation efficiencies, as they look to renew the heating industry. As a result of Heat Geek’s courses, installers have joined the growing network of ‘Heat Geeks,’ allowing them to grow their businesses.


  • H&V News Training Initiative of the Year 2022
  • National Energy Efficiency Awards 2023: Energy Efficiency Champion of the Year (Adam Chapman)

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