Technical data

3
1.0 general
STRATA2
1.1 general notes
These instructions are intended to assist the installer, commissioning engineer, maintenance engineer
and user with the installation, maintenance and usage of the Strata 2-120 gas fired condensing boiler.
Please read this manual fully before commencing the installation of the appliance. MHS Boilers Ltd shall
not be responsible for any damage resulting from failure to carefully observe the instructions given.
The Strata 2-120 must only be installed by persons deemed to be competent i.e. Corgi Registered. This
manual must be handed to the user following completion of the installation.
1.2 certification details
The Strata 120-2 complies with all relevant European Directives and has been independently certified
to comply with the requirements of prEN 483 for use in GB and IE with Gas Category II2H3P.
(Natural gas G20 @ 20 mbar inlet pressure).
The flue classification (depending upon the required flue option) is either B23; C13X; C33X; C43X;
C53X; C63X; C83X.
CE
0063AT3426-98
2.0 product
description
The Strata 2-120 boiler is a gas-fired, fully condensing floor standing appliance with a fully modulating
output of 12.2 to 119.7 kW at 30ºC return water temperature. The appliance may be used singularly or in
multiples serving the needs of LTHW systems up to a maximum flow temperature of 85ºC.
Each Strata 2-120 boiler incorporates two modules, each module accommodates its own burner,
combustion fan, gas valve, ignition/ionisation, electrode and burner control with safety circuits.
Each module contributes 50% of the total output, and can be operated independently. Each heat
exchanger has a modulating capacity of 20% to 100%. If a fault should occur with one of the burner/heat
exchanger modules, the other will continue to operate.
The boiler includes, as standard, matched modulating speed pumps which automatically adjust the
primary flow rate for the heat exchangers to (where possible) maintain the design temperature difference.
The pumps have residual duty to convey the boiler mass flow rate to the installers system low loss manifold,
ensuring correct flow rates through the boiler at all times and reduces installer involvement in this
critical area.
The Strata 2-120 incorporates comprehensive microprocessor controls. A RVA47 (CLI) cascade
manager is used to translate the heat demand of the installation into a boiler load for each module. The
first RVA47 (CLI) manager has the potential to control up to four modules (burner/heat exchangers) in
modulating/cascading fashion. Therefore when installing Strata 2-120 boiler in twin form, all serving the
same system, an RVA47 (CLI) controller is only required and supplied in the first boiler.
The RVA47 (CLI) controller in boiler no.1 is always the ‘master’ and every subsequent controller must
be set as a ‘slave’.
In addition to the RVA47 (CLI) controller, each Strata 2-120 boiler incorporates individual burner/heat
exchanger safety controls which provide the essential safety functions of burner ignition and flame
monitoring, overheat cut off devices for excessive water or flue gas temperature, an LCD display screen
to indicate run or fault status codes, and individual burner on/off switches.
Room Sealed Option
When required, the Strata 2-120 boiler, may be installed as a room sealed appliance, taking air for
combustion from outside the building. This option is recommended for installations where air from within
the building may be contaminated with oxidising agents, which occur in appliances such as swimming pool
plant rooms, dry cleaners and in various manufacturing and industrial process environments etc.