Specifications

Logamax plus GB142 applications manual | 01.2012 Technical specifi cations are subject to change without prior notice
GB142 Applications Manual
| 27
3.1 System 1: Single boiler with outdoor reset, multiple heating zones
with zone pumps and DHW
Summary:
Single boiler supplying multiple heating zones equipped
with 3rd party thermostats and zone pumps. This system is
recommended if pressure drops in individual zones are too
great to be served by a single system pump (see system 2).
• High efficiency outdoor reset controlled system based on
heat loss of the structure
• Outdoor reset for system supply water temperature
• Zone pumps are controlled by 3rd party relay panel and
individual room thermostats
• Optional DHW tank loading with or witho ut priority
In detail:
The AM10 outdoor reset controller receives a heat demand from
the zone thermostats via a closed contact and computes the
system supply water temperature based on information from the
outdoor sensor and the heating curve.
Applications include multiple zones at the same temperature,
or zones at different temperatures if thermostatic or externally
controlled motorized mixing valves are used.
The AM10 provides warm weather shutdown.
The modulating boiler strives to run at low fire for the longest
time possible where efficiency is at its highest.
DHW is heated based on the signal from the DHW tank sensor
FW. DHW is generated in parallel with space heating if both are
calling simultaneously. For faster DHW recovery, install a relay
that disables zone circulators while the tank loading pump is
activated. Alternatively a zone relay panel with DHW priority can
also be used.
The low loss header decouples the boiler loop from the system
loop.
Required components:
• GB142 boiler
• AM10 controller (incl. with GB142)
• PH zone circulators
• PS DHW tank loading circulator
• ECM pumps (low energy or constant pressure pumps) are
recommended for constant flow rate and additional energy
savings.
• DHW tank
• Multi zone pump relay panel with/without DHW priority
• PS DHW tank loading circulator
• Zone thermostat per room/zone
Additional instructions:
See manufacturer’s installation and operating instructions for
details on 3rd party components.
The system shown generates DHW with priority over space
heating.
If the DHW sensor in the tank reports a call for DHW, the boiler
will ramp up the supply temperature according to the DHW
setting overriding the outdoor reset heating curve.
The boiler has DHW priority built in. Use the DHW sensor with
the DHW tank and select the DHW temperature using the boiler
dial. During a DHW call the PS tank loading pump will run and
the PK boiler pump will be off. Once DHW is satisfied the boiler
will return to space heating.
If DHW is not installed, set the DHW dial to OFF.