gledhill StainlessLite HP180IND, Design, Installation & Servicing Instructions

Page: 14 / 32

Page 14
Heating And Primary Systems
Although the heat pump and the primary
heating system should be sized and installed in
accordance with BS 5449 the following should
also be taken into account during the design
and installation phase.
The heat pumps normally operate at lower fl ow
temperatures; typically 45 – 55°C compared
with 75 – 80°C for the boilers. Therefore if
traditional radiators are used then, these should
be oversized in accordance with the heat pump
manufacturers recommendations.
For optimum effi ciency (i.e. COP of a heat pump),
low temperature under fl oor heating system
should be considered.
The heat pumps normally operate at lower
temperature difference between flow and
return compared with the traditional boilers
and therefore when sizing the pipework heat
pump manufacturers recommendations should
be taken into account.
Safety
Stainless Lite HP is fitted with a combined
temperature and pressure relief valve to cope
with any increase in temperature and pressure
in the cylinder above the design limits, when
used with heat sources up to 45kW total
output. This is the maximum heat input to the
cylinder allowed by section G3 of the ‘Approved
Document G’ of the Building Regulations.
The heat supply to the cylinder and hence the
temperature of the stored water should be
controlled as outlined below: -
• Heat supply from the primary heat source
i.e. heat
The 2-port spring return motorised valve
supplied should be fi tted adjacent to the unit
and controlled by the cylinder thermostat
(combined control and overheat thermostat)
supplied with the unit. The motorised valve
and the thermostat must be wired so that the
motorised valve switches off when either the
control thermostat contact breaks when the
set temperature is reached or the overheat
thermostat contacts break when an overheat
condition develops. The operation of the
heat source should be controlled via the
auxiliary switch of the motorised valve.
It is important to follow the wiring diagrams
in the wiring section of these instructions.
Schematic Open Vented Primary System
Heat Pump
Pump
150mm max.
Warming/Overflow
Pipe
F & E Cistern
Minimum
distance as
required by
heat pump
manufacturers
instructions
Motorised Valve
Motorised Valve
(Energy cut-out)
Schematic Sealed Primary System
Motorised Valve
Motorised Valve
(Energy cut-out)
Expansion
Vessel
Gauge
Safety Valve
Pump
Heat Pump
INSTALLATION
INSTALLATION