20. Hydraulic
Requirements
The boilers are intended to be used in
conjunction with FULLY PUMPED, SEALED
systems subject to the requirements below.
They are NOT SUITABLE for use on gravity
circulation systems. The boiler must NOT
be used for direct hot water supply.
Underfloor Systems
Despite the low boiler flow
temperatures feature, in the event of control
and/or mechanical failure or incorrect
adjustment, to prevent damage to the
installation or associated pipe work ALL low
temperature under floor installations require
an obligatory mixing valve installing as part
of the system controls or a high limit
thermostat set at 60
o
C to interrupt the
demand for heat signal from the underfloor
heating controls.
EC38S and all Combi Types
In hard water areas suitable protection
should be provided to prevent the build up
of deposits in the primary hot water heat
exchanger. The appliance guarantee does
not extend to failure as a result of lime scale
or other contamination.
38kW Models Only.
These appliance requires an expansion
vessel and a 3 bar pressure relied valve to
be fitted to the system
MAKE SURE ASUITABLE SIZED
EXPANSION TANK AND A 3BAR
PRESSURE RELIEF VALVE ARE FITTED
TO THE SYSTEM AND THE DISCHARGE
PIPE TERMINATES TO A SAFE
LOCATION
The central heating system should be in
accordance with the recommendations
given in BS. 6798 and BS. 5449.
Hot water cylinders must be double
feed indirect and to aid efficiency and fast
recovery times (all appliances are hot water
priority) should be of the high recovery type.
Recommended minimum coil capacity
25kW.
The boiler must be capable of being
adequately vented of air. Drain taps MUST
be located in accessible positions, which
permit the draining of the whole system -
including the boiler and hot water storage
vessel. Drain taps should be at least 1/2
inch BSP nominal size and be in
accordance with BS. 2879.
In
order to facilitate servicing of the
unit, full flow isolating valves must be fitted
to all water and gas connections, (these
valves can be supplied by eco hometec as
an optional extra if required).
20.1
Expansion Vessel
Depending on specification chosen the
appliance may be fitted with a 10 litre
expansion vessel.
An expansion vessel must be
fitted to all systems and for those boilers
supplied with an expansion vessel if the
system water content exceeds the limit an
additional vessel will be required.
For systems having a larger water capacity,
multiply the total water content (boiler and
system) by the factor to obtain vessel size in
litres.
T
T
a
a
b
b
l
l
e
e
1
1
0
0
E
E
x
x
p
p
a
a
n
n
s
s
i
i
o
o
n
n
V
V
e
e
s
s
s
s
e
e
l
l
R
R
e
e
q
q
.
.
*Vessel Charge & Initial System Pressure
*VC&ISP
0.5 bar
1.0 bar
1.5 bar
Factor
0.08 bar 0.11 bar
0.16 bar
EXAMPLE 1.
Central heating system filled to 1 bar.
Total system water content 60 litres
Multiply 60 (water content litres) x 0.11
(factor from chart) = 6.6 litres.
Vessel required 6.6 litres.
Vessel supplied 10 litres.
Vessel adequate.
EXAMPLE 2.
Central heating system filled to 1 bar.
Total system water content 150 litres
EC 16~38 Installation Manual page
29
