️🚨 This product is no longer manufactured

The descriptions and diagrams below are for information only.


HeatMaster 25 C

Combined gas fired condensing boiler and water heater with stainless steel heat exchanger

  • Tank-in-Tank
  • BIM Objects
  • Nat Gas and LPG
  • Domestic and Commercial
Short Energy Label Heating
Short Energy Label DHW
  • label_energy_GAS
  • Boilers
  • DHW Production
  • Standard
  • Concentric
  • Floor installation
# GTIN : 5400891032206
# P/N : XB600002
  • Heating and hot water from one unit saves space, reduces energy use and speeds up installation
  • Operates in most efficient mode (condensing) for heating
  • Low maintenance with no anode protection required
  • Easy to use standardised controls using ACVMax control system
  • Low NOx levels – this model qualifies for 2 credits under BREEAM New Construction 2018 (<24mg/kWhr)
  • Suited to smaller premises and lower flow rate requirements (smaller DHW tank than 25TC)
  • Corrosion-resistant stainless steel heat exchanger, reduces maintenance and increases system lifespan
  • Suitable for unvented systems – supplied with 3.5 bar mains unvented kit and DHW mixing valve
  • Supplied with LPG kit for on-site conversion
  • Reduces legionella risk due to temperature stored at > 60°C
  1. Concentric flue gas/air inlet box
  2. Flue gas exhaust tube
  3. Combustion chamber
  4. Stainless steel heat exchanger
  5. Stainless steel “Tank-in-Tank” hot water production tank
  6. DHW circuit tube
  7. Condensate recovery dish
  8. High efficiency circulator pump
  9. NTC sensor (heating circuit)
  10. Pressure sensor
  11. Electrical panel (with spare fuses at the back)
  12. ACVMax Control panel
  13. DHW tank dry well (Sparge tube with temperature sensor)
  14. Automatic air vent
  15. Gas pipe
  16. Gas valve
  17. Connection for DHW safety valve (to be installed)
  18. Modulating air/gas premix burner with fan
  19. Air inlet

Constructive characteristics

Capacity (total) 200 L
Capacity (primary) 120 L
Capacity (domestic hot water) 80 L
Capacity expansion tank(s) - L
Chimney: Max pressure drop in flue pipe 130 Pa
Chimney: max length of concentric flue pipe 20 m
Chimney connection 80/125 Ømm
Connection - heating 1 F Ø"
Connection - DHW 1 M Ø"
Connection gas 3/4 M Ø"
Connection - safety valve 1/2 M Ø"
Max operating temperature 87 °C
Water pressure drop boiler at Δt = 20°C 3 mbar
Max service pressure heating (primary) 3 bar
Max service pressure (DHW) 8,6 bar
Height when tilted 1855 mm
Weight (empty) 174 kg

Heating characteristics

Pre-heating time from 10 to 80°C (Heat source: boiler) 27 min
Heating time from 10 to 90°C 40 min


Input max (heating) HCV 27,8 kW
Input max (heating) LCV 25 kW
Combustion efficiency 97,5 %
Efficiency at 30% load (EN15502-1) 109,0 %
Efficiency (max output) 80/60°C 98 %
Efficiency (min output) 80/60°C 98 %
Efficiency DHW mode ΔT 30K 99,2 %
CO emissions max output 27 ppm
CO emissions min output 6 ppm
Mass rate of combustion products (gas) 42 kg/h
NOx weighted (GCV) (EN15502) 26,3 mg/kWh
NOx class (EN15502) 6
Nominal power DHW 25 kW
Output power max (80/60°C) 24,3 kW
Output power min (80/60°C) 4,9 kW
Gas flow rate (min output) 0,5 m³/h

Domestic hot water performance

Peak flow at 40°C 233,5 L/10’
Peak flow 1st hour at 40°C 748 L/60’
Continuous flow at 40°C 617 L/h
Peak flow at 60°C 145 L/10’
Peak flow 1st hour at 60°C 478 L/60’
Continuous flow at 60°C 400 L/h

Electrical Characteristics

Voltage 230 V
Frequency 50 Hz
Protection IP 20
Electrical consumption 95 W
Electrical power requirements 0,8 A

Eco Design Fields

Space heating energy efficiency class A
Seasonal space heating efficiency (35°C) 93 %
Declared load profile XXL
Water heating energy efficiency class B
Water heating energy efficiency [ηwh] (EU 814/2013 Art 2 (15) Ann.IV-3) 74 %
Sound power level indoors LWA 60 dB
Energy Label EU
Product Fiche

Marketing brochure

ACV UK Product Guide

9.61MB – en

Technical brochure

HeatMaster C, TC

11.41MB – en

ACVMax - Installers handbook for heating systems controlled with ACVMax (3.06-3.16)

21.45MB – en

HeatMaster 25 / 35 / 45 / 70 / 85 / 120 TC (V15) - Installation, Operation and Maintenance instructions

13.00MB – en

HeatMaster 25 C Data Sheet

509.87kB – en

HeatMaster TC - Installation, operations and maintenance instructions

5.79MB – en


Energy Label EU

Product Fiche

BIM Files

BIM Files

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