Pump; Bypass; Inhibitor; Open (Vented) Water System - Vaillant ecoMAX pro SERIES Instructions For Use Installation And Servicing

Water system 5
450mm
MIN.
HEIGHT
1000mm
MIN.
BOILER
150mm MAX.
Fig. 5.3
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 Flow rate

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 pla-
ced at least 1.5 metres away from the boiler.
10
Open (vented) system.
Recommended
relationship between
pump, cold feed and vent.
22mm (MIN.) VENT
FEED AND
EXPANSION CISTERN
15mm (MIN) COLD FEED
15mm (MIN.) BY-PASS
(if required)
PUMP

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 cylinders.
Instructions for Use, Installation and Servicing ecoMAX pro