Dorchester DR-XP stainless steel water heater
Dorchester DR-XP stainless steel water heater

Fully automatic, condensing direct fired water heater with stainless steel tank for domestic hot water.

2 models available with continuous outputs (@44°C ∆T) of 710 & 910l/h.

93% Gross Seasonal Efficiency
Fuel NG LPG product icon
Warranty 2 product item
ErP Part L Compliant product icon

Product information

    • Power outputs of 35 & 46kW
    • Storage capacity of 184 litres for both models
    • Quick setup and installation thanks to the plug and play technology
    • Fully room sealed with flexible flue options enable installation almost anywhere in the building 
    • Easy to use LCD touch screen display for simple operation, control and fault diagnostics
    • Lower costs and less maintenance - no anode protection required due to a stainless steel tank
    • Reduces energy use and running costs by maximising condensing water heater performance
    • Load profiles of XXL and an A energy rating ensure full compliance with the ErP (Energy-related Products Directive)
    • Natural gas and LPG water heater options enable installation in off-grid locations
    • All components accessible from front for ease of service and maintenance 
    • Full project assistance available from our dedicated hot water expert to help with hot water sizing and selection of equipment to match the application.
    • Extensive back up and support from our team of experienced engineers across the UK.
    • Long-term commitment to spare parts
    • Available for next day delivery (dependent on stock availability, charges apply, order cut-off 12pm).

Technical data

Units DR-XP 35-200
Continuous output with 44°C ΔT l/h 710
1st hour output with 44°C ΔT l 1100
Continuous output with 50°C ΔT l/h 620
1st hour output with 50°C ΔT l 870
Continuous output with 55°C ΔT l/h 570
1st hour output with 55°C ΔT l 770
Storage capacity litres 184
Maximum working pressure kPa (bar) 800 (8)
ErP load profile - XXL
Water heating energy efficiency % 93
ErP efficiency rating - A
Heating-up time, ΔT = 44°C min. 17
Heating-up time, ΔT = 50°C min. 18
Heating-up time, ΔT = 55°C min. 19
Nat Gas
Input, gross – maximum kW 37.8
Input, net - maximum kW 34.9
Output – maximum kW 35.9
Gas inlet pressure – nominal mbar 20
Gas flow rate – maximum @1013.25 mbar and 15°C m3/h 3.7
Input, gross – maximum kW 37.0
Input, net - maximum kW 33.4
Output – maximum kW 34.9
Gas inlet pressure – nominal mbar 37
Gas flow rate – maximum @1013.25 mbar and 15°C m3/h 1.4
Mass flow rate flue gases Nominal/minimal @15°C, 9% CO2, N.T.P. (Nat. Gas - G20) kg/h 61/42
Flue gas temperature – maximum °C 65.0
NOx emission, dry air free, European Class 6. Maximum (at part load) mg/kWh 53
Pressure at the flue outlet only (B23) with zero pressure at air inlet Pa 176
Power consumption W 160
Electrical supply Vac 230V 1PH 50Hz
Voltage tolerance % of Vac (-15+10%)
Sound level dB 63
Weight when empty kg 79
Approximate shipping weight kg 97
Maximum floor load/ weight filled with water kg 261


Dorchester DR-XP water heater brochure

Product brochures 3750 kb

Dorchester DR-XP water heater installation, commissioning and operating manual

Installers guides 5250 kb

Ideal uses/applications

  • New build projects
  • Small to medium sized commercial and public buildings including schools, hospitals and hotels.
  • Soft water areas including Scotland and the South West

Optional extras


  • Unvented water supply kit - essential for any unvented application. Includes an expansion vessel sized for the water heater and local pipework only.
  • Room Sealed Flue Systems:
    • Concentric flue systems type C13–Horizontal termination
    • Concentric flue systems type C33–Vertical termination
  • Twin duct flue systems type C53–Vertical flue termination with Horizontal air inlet
  • Conventional Open Flue Systems:
    • Open flue systems type B23–Vertical termination

Choose from a wide range of service contracts to help maintain optimum performance of your water heater.

Book commissioning at the same time as placing your order for improved warranty terms.

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