
5
Feed and Expansion Tank:
1. Feed and Expansion tanks should be sized to allow for suitable expansion of all primary water,
equal to 4% of the entire system volume, including cylinder and pipework. Allowance should be
made for cold fill level, and a minimum of 30mm from position of overflow, and 60mm from cold
inlet position. As a rule of thumb, pick a header tank with a capacity of 10% of system volume.
2. Where wood burners are connected to system, a metal feed and expansion tank should be used,
along with a copper float on inlet valve.
3. An overflow must be connected that is rated to 100°C, continually falling, and is capable of
discharging the full failure flow rate of the inlet valve (with float removed). This must be checked
during commissioning.
4. Feed and Expansion Tanks should be insulated.
5. The vent pipe should be taken to a level 300mm higher than top of the F&E tank, before
connection through lid or into side at high level (30mm above overflow connection). If this is not
possible then it may be necessary to tee the cold feed into the vent
pipe (rather than the connection provided on the Xcel), via a return drop
of at least 300mm (see diagram).
6. Vent pipes must be continually rising from the Xcel. Horizontal runs
should have a slight incline.
7. Do not install separate vents, or cold feeds, at different points in a
system that shares flow. Any pumped flow will generate a pressure
difference along pipework, and this will cause circulation through the
F&E tank, heating it up, and mixing oxygen into the system,
accelerating system corrosion.
8. See Assembly X2009-19P for manually filled (no-discharge) systems.
9. Spare Parts
(a) Metal F&E Tank (400 litre systems) ........... 7067441
(b) Metal F&E Tank (800 litre systems) ........... 7067442
(c) Ball Float Valve
(d) Copper Float for float valve ....................... 7058763
(e) Tank Connector, 22mm Compression ....... 701022
Pressurised Storage Systems:
1. INSTALLATION AND MAINTENANCE OF PRESSURISED STORAGE SYSTEMS MUST BE DONE BY REGISTERED UNVENTED
PERSONS ONLY.
2. SYSTEMS MUST BE SERVICED ANUALLY, WITH ALL SAFETY VALVES TESTED.
3. SERVICING MUST BE RECORDED ON A LABEL SECURELY ATTACHED TO TORAGE UNIT.
4. SYSTEMS MUST NOT BE CONNECTED TO HEAT SOURCES (THAT CAN ACHIEVE > 90°C) WITHOUT THERMOSTATIC CONTROL,
OR WITHOUT THE FACILITY TO BE TURNED OFF VIA CONTROL THERMOSTATS, UNLESS SUITABLY APPROVED PROTECTION
HAVE BEEN PROVIDED.
5. DO NOT use O-Ring Seals on Immersion Heaters. If factory fitted then they should be replaced with PTFE string, and a fibre washer.
6. The following safety controls must be installed
(a) Expansion Vessel of size equal to, or greater than, 25% of total system volume, and having a pre-charge pressure between
0.9 and 1 bar.
(b) 2.5 bar Expansion Relief Valve, connected to a bottom (cold feed) connection on the Xcel, or adjoining pipework (without
possibility of isolation from the Xcel).
(c) 3 bar, 90°C Pressure and Temperature Relief Valve, connected directly to top (vent) connection on the Xcel.
(d) 1 bar RPZ (Reduced Pressure Zone) Automatic Filling Valve (requires discharge).
(e) Pressure Gauge and Temperature Gauge.
(f) Discharge pipe capable of removing the combined maximum discharge from all three safety valves.
7. Spare Parts
(a) Expansion Vessel, 80 litres ............................................................... 70101699
(b) Expansion Vessel, 80 litres. .............................................................. 70101700
(c) Expansion Vessel, 110 litres ............................................................. 7026118
(d) 2.5 bar Expansion Relief Valve ......................................................... 70674
(e) 3 bar, 90°C Pressure and Temperature Relief Valve ........................ 7069034
(f)
1 bar RPZ Automatic Filling Valve ..................................................... XVES
(g) Temperature and Pressure Gauge .................................................... 702308
(h) Temperature Gauge .......................................................................... 7014269
Straight Neck ...................................... 7068970
Swan Neck ......................................... 7059745