Built to perform

  • Features and benefits
  • Specifications
  • Literature
  • Case studies
  • BIM
  • Enquiry
  • Energy labelling

  • Up to 15 litres per minute
  • Internal or external models available
  • Copper finned tube heat exchanger
  • 5:1 fully modulating burner
  • Flexible flueing options
  • Compact, light and robust construction
  • Factory fitted frost protection
  • WRAS approved
  • Satisfies the most demanding applications
  • Flexible siting, especially where space is at a premium
  • Low maintenance, reliable and robust
  • Adjusts the burner to meet the desired water temperature with no stand-by heat loss
  • Can be installed quickly, saving time on site
  • Complies with the Water Supply (Water Fittings) Regulations and Scottish Byelaws

View product specification

When clicked this will open the product specification in PDF format.



Natural Gas: WH42 WH56 WHX56 WHC56
  Propane: LWH42 LWH56 LWHX56 LWHC56
Heat input (gross) kW 49 62.3 62.3 62.3
Heat output kW 42 55.8 55.8 55.8
Gross thermal efficiency % 86 90 90 103
NOx emissions (0% 02) natural/propane mg/kWh 92/106 92/106 106/128 106/123
NOx emissions (0% 02) natural/propane ppm 52/60 52/60 60/72 60/72
ErP efficiency rating     B
Gas data
Gas flow rate (natural gas) m3/h 5.1 6.5 6.5 5.1
Gas flow rate (propane) m3/h


2.5 2.5 N/A
Storage capacity Litre N/A N/A N/A N/A
Recovery rate at 50ºC rise Litre/hr 720 956 956 956
Recovery rate at 56ºC rise Litre/hr 642 854 854 854
Operating pressure bar 3.5 3.5 3.5 3.5
Minimum working pressure bar 0.2 0.2 0.2 0.2
Maximum pressure bar 10 10 10 10
Depth mm 240 240 240 240
Width mm 450 450 450 465
Height mm 615 615 615 615
Flue diameter mm 100 100 100 100
Fuse rating amp 10 10 10 10
Electrical power consumption W 89/85 120/112 83 140
Noise level dBA 49 49 49 49
Weight full kg 30 30 31 30
Weight empty kg 29 29 30 29


Learn more about the FASTflo+ by downloading product literature. If you can’t find the literature you are looking for, or you have any questions, please contact your Area Sales Manager who will be able to help.

Find out more about the FASTflo+ by reading the case studies below.

New multi level BIM files coming soon for this product

The Andrews Water Heaters BIM library is being updated to comply with CIBSE PDT standards. If you require CIBSE compliant BIM files for this product, please fill out the form to receive new BIM files when they’re available and we will send them to you as soon as they’re ready. In the meantime, standard BIM files are available to download using the links below. If you can’t find the BIM file you require, or you have any questions, please contact your Area Sales Manager who will be able to help.

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FASTflo+ energy labels

Fastflo plus energy label WHC42 and LWHC42 updated 28/09/2015 (0.09MB) Fastflo plus fiche updated 25/09/2015 (0.07MB) Fastflo plus energy label WHC56 and LWHC56 updated 25/09/2015 (0.25MB) Fastflo plus technical parameter sheet updated 25/09/2015 (0.05MB)

Andrews Water Heaters

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