The company reserve the right to alter size, shape and specification without prior notice
TMS-UT-0804-Z01-4
page 3
TERMINOLOGY USED IN THIS MANUAL
The central heating boiler water circuit is called primary
1. Introduction
Thank you for purchasing the Oso Termo E electric central heating boiler.
To ensure a correct and safe installation and economical use, please read these instructions thoroughly before
installation.
1.1. Applicable documents
The following additional documents are provided with the appliance:
For the owner of the system:
Instructions for use
Warranty card
For the qualified technician:
Instructions for installation
Electrical drawing for the appliance
1.2. Retention of documents
Please pass on this installation manual to the owner of the system. The owner should retain the manuals so that
they are available when required.
1.3 Termo - E concept
The Termo Plus E is a wet system electrically heated boiler for space heating only. It is not suitable for use with
an indirect water heater and should not be used under any circumstances to heat domestic hot water.
The boiler provides wet system central heating by passing the primary water over the immersion heaters. The
immersion heaters are located on the under-side of boiler ensuring the elements are constantly immersed in the
heating medium (water with appropriate inhibitor).
Termo Plus E uses weather compensation/heat curve technology. An outside sensor supplied with the boiler
informs the boiler of the outside temperature. This information is used by the boiler to set a temperature in the
heating system. The colder the external temperature, the more internal heating is required.
The boiler is supplied with a range of heat curves built into its software. Once correctly set, the heat curve need
never be altered. Heat curves are set according to the insulation levels of the property. A poorly insulated house
will require a higher primary heating temperature.
Selecting the heating curves at the time of installation is a simple process for the installer. A table is shown on
page 13 indicating which heating curve is required for the building type. Once the heating curve is correctly set, it
should never require changing.
The heating curve will aim for the property to be heated to 22°C. Not all households wish for the same internal
temperature, if the residents of the property require a higher or lower temperature, the selected curve should be
offset up or down by the appropriate number of degrees. Full instructions are given on page 14.
A room thermostat (not supplied) must be installed to finely regulate internal temperatures.
Heat curve systems operate for longer periods at lower temperatures than traditional systems and can typically
make savings of up to 15% over a standard heating system. Heat curve systems are widely used in Europe but
relatively new in the UK.
Heating curves also vary according to radiator or under-floor heating. The factory set heating curve is for a
building constructed to 2000 building regulations with radiator heating. Many boilers therefore will not require
adjustment of heating curve.
The boiler will modulate 1, 2 or 3 elements to achieve the desired primary temperature. The boiler reservoir is
insulated with 19 mm self-extinguishing Armaflex insulating material, which is sufficient to direct the whole heat
only to the heating system.
The boiler operates by rapidly heating a small water quantity. Energy use is maintained at 100% efficiency.
No flue or fan required - Almost silent in operation - No bulk oil storage tanks required
No annual safety check required
