Technical data

Instructions for Use, Installation and Servicing ecoMAX pro 11
5.3 Pump
The pump should be fitted on the flow pipe from the 
boiler and have isolating valves each side.
A variable duty pump should be set to give a  
temperature difference of no greater than 20 °C 
between the flow and return, with the thermostat set 
at “MAX”, which is about 80 °C, to give a flow rate as 
shown in table 5.1.
See chart for pressure loss of the boiler, Fig. 5.1 or 5.2.
High resistance microbore systems may require a higher 
duty pump.
5.4 Bypass
A bypass is not required on the central heating system 
unless all radiators are fitted with thermostatic radiator 
valves or the system controls could allow the boiler and 
pump to operate when there is no flow. 
Where a bypass has to be fitted, the bypass must be 
placed at least 1.5 metres away from the boiler.
5.5 Inhibitor
Attention is drawn to the current issue of BS 5449 and 
BS 7593 on the use of inhibitors in central heating 
systems.
If an existing system is to be reused take special care 
to drain the entire system, including the radiators, then 
thoroughly cleaning out before fitting the boiler whether 
or not adding an inhibitor.
For advice please refer to 5.10, Water Treatment.
5.6 Open (Vented) Water System
The boiler must be supplied from an unrestricted water 
supply taken from a feed and expansion cistern situated 
at a maximum height of 27 metres (90ft) above the 
boiler.
The cold feed must be 15mm minimum size.
The vent must rise continuously and be unrestricted.
It is important that the relative positions of the pump, cold 
feed and open vent are as shown in Fig. 5.3.
5.7 Domestic Hot Water Cylinder
WARNING: 
 Single feed indirect cylinders are not suitable.
The domestic hot water cylinder must be of the double 
feed fully indirect coil type.
5.8 Domestic Hot Water System - unvented
Where a storage system will not have a vent to 
atmosphere the installation must comply with the 
Building Regulations and local Water Company bylaws, 
see also the current issue of BS5546 and BS6700. In IE 
the requirements given in the current edition of IS 813 
and the current Building Regulations must be followed. If 
fitting to an existing system the local authority should be 
informed.
NOTE: 
ecoMAX pro boilers are not suitable for use 
with Vaillant VANTAGE unvented cylinders and 
MUST not be used in connection with these cyl
-
inders.
  Model    Minimum flow rate   
  ecoMAX pro 18 E    773.8 litres/hr
  ecoMAX pro 28 E    1289 litres/hr
      This is equal to 20 °C differential at maximum heat input.
TABLE 5.1
Fig 5.3
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