Connect The Water Supply - Potterton Powermax HE 85 Litre Installation And Servicing Instructions

2.4 Connect the Water System
See Figs. 10 and 11. Observe guidance provided in
Section 1.6. Always tee the cold feed to shower fittings
(and other mixer fittings) into the pipe supplying the hot
water store i.e. downstream of the Inlet Control Group.
This will ensure a balanced pressure supply to the
shower(s).
Future maintenance and servicing operations will be
simplified if the Inlet Control Group can be mounted
above the DHW store as indicated in Fig. 11. Both the
Inlet Control Group and the expansion vessel can be
sited away from the boiler e.g. to supply reduced
pressure to all the system, but it is essential that no valve
is fitted in-line between the store and either of these
components.
Solder Flux
Use water-soluble flux for making soldered capillary
joints in the primary circuit. Traditional grease-based flux
containing zinc chloride must not be used.
CH System Connections
The flow connection is on the LH side of the unit as
indicated. The return connection is low down at the front
centre. Pipework can be run inside the casing but must
not prevent the removal of the immersion heater (if fitted)
or obstruct access to condensate trap.
Pressure Relief Valve
A pressure relief valve set at 3.0 bar is fitted to the
primary pipework near the top of the tank. See Fig. 10.
Manual Air Vent
Using the manual air vent, thoroughly vent air from top
of the heat exchanger when filling the system to save
time during the boiler commissioning. Note: 1/4" dia.
manometer tube fits the manual vent.
Central Heating Pump & System By-pass
The central heating pump is factory fitted and an
automatic system by-pass is provided. The boiler can be
used in systems controlled by thermostatic radiator
valves (TRVs) but it is essential that the by-pass isolating
valve is fully open.
The circulating pressure and flowrate available for the
central heating system is shown opposite with the by-
pass in circuit.
18
Installation
For most systems, pump speed 2 will suffice. Using
speed 1 will impair domestic hot water recovery. Speed
3 will be required for high resistance systems such
as those controlled by TRVs and/or utilising plastics
minibore pipework.
Graph of Central Heating Head vs. Flow
m
4
3
2
1
0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
Secondary Circulation
A pumped secondary circuit, if required, can be
connected by teeing into the 22 mm DHW Outlet pipe
and the 22 mm Cold Inlet pipe. Note: This is not
recommended for models having a secondary store of
less than 150 litres.
A single check valve (spring loaded type) should be fitted
in the return from the secondary circuit. All component
parts of a secondary circuit must be suitable for
operation at temperatures up to 65
to 8 bar.
N L T T N L F HW HW CH CH
R L 2 2 R R L R L
From secondary circuit
3
2
Flow litres/min.
and pressures up
°C
To secondary circuit
RWC
Check Valve
Publication No. 5106226
MAX0063A