Fabdec EXCELSIOR Installation Manual - page 12
12
Cold Water Valve
The combined cold water valve (supplied) can be connected anywhere on the cold water mains prior to the unit. It can be
located at a point near to where the mains supply enters the premises if this is more convenient. When installing the cold
water valve, ensure that the arrow is pointing in the same direction as the mains water supply flow when connecting (see
figures 5 and 6).
The cold water balancing port, on the valve, allows you to connect the cold water mains to the rest of the property thus
giving balanced pressure throughout
.
If this facility is not required leave the cap on.
Check Water Pressure & Flow Rates
Fabdec suggests 1.5 bar pressure & 20 litres/minute flow rate to be the minimum requirements for satisfactory operation.
The unit will still operate below this, but it will not be possible to run two or more outlets at the same time.
The mains supply must not exceed 3 bar. If it does a special pressure-reducing valve will be required.
Consideration should be given to the routing of the discharge pipe and the location of the solar panel or alternative energy
source where applicable.
Drain Tap
A drain tap to drain the unit must be fitted to the cold-water inlet pipe between the Excelsior cylinder and the cold water
valve assembly at its lowest level possible (see figures 2, 3 and 5).
Pipework to Taps
Ideally a 22mm pipe should supply the outlets throughout the property with short lengths (max 1 metre) runs of 15mm
going to baths, showers, and basin taps. Smaller bore pipe can be used to suit taps.
Taps & Fittings
All taps and fittings incorporated into the unvented system should have a rated operating pressure of 7 bar or above.
Inlet Group
The inlet group will vary depending on whether the vessel is fitted as internal or external expansion (see figures 2, 3, 5
and 6).
Primary Circuit
The motorised valve supplied and the thermal cut-out (high limit stat) must be fitted to the primary flow (Use compression
fittings only).
Operation of the cut-out & motorised valve
To comply with regulations and to prevent the temperature reaching 100°C the thermal cut-out supplied must be fitted.
The thermal cut-out is wired in series to the cylinder thermostat. When the thermal cut-out senses an abnormal rise in
temperature in the primary flow the electrical supply to the motorised valve will be cut and the valve will return to the
closed position. This will cut-off the primary water from the boiler to the indirect coil in the cylinder.
If the thermal cut-out operates it must be reset manually. Check the cylinder stat and/or boiler stat.
Primary Circuit (Excelsior Solar)
Excelsior solar cylinders are suitable for connecting to a solar collector system and, where a twin coil is present (indirect)
to a gas or oil central heating boiler.
WARNING: SOLID FUEL OR WOOD BURNING BOILERS AND GRAVITY CIRCULATION SYSTEMS MUST NOT
BE USED ON THE PRIMARY CIRCUIT OF AN UNVENTED HOT WATER SYSTEM.
The cylinder should be installed in accordance with the solar installation instructions for connection to the primary flow and
return.
The Excelsior Solar range must only be connected to solar installations containing a hydraulic station with two non-return
valves (one in the flow to the collector and one in the return).
This will prevent thermal siphoning of the heat transfer fluid
when the pump is switched off
.
Where two non-return valves are not present or a hydraulic station is not used in the solar system, a second two-port valve
must be installed into the flow of the solar coil and wired to the lower two-port valve.
The Excelsior Solar is supplied with one two-port motorised valve which should be connected in the flow to the auxiliary
coil and wired to the upper twin thermostat of the cylinder.
Solar pump: The lower twin thermostat should be connected in line with the solar pump power supply.
The factory fitted temperature and pressure relief valve should not be removed from the cylinder or tampered
with in any way. The valve is pre-calibrated to open at 7 bar or 90°C and any attempt to adjust it will invalidate the
warranty and could affect the safety performance of the unit.