MEGAFLO Commercial 1000, Product Manual

Page: 21 / 40

Unvented Hot Water Cylinder
21
INST
ALLA
TION AND
COMMISSIONING (2)
Primary circuit
Boiler Selection
The Megaflo Commercial Indirect models are suitable for use with most gas or oil fired boilers com-
patible with unvented systems i.e. fitted with a temperature control thermostat and thermal cut-out.
If in doubt consult the boiler manufacturer. Solid fuel boilers or any other boiler in which the energy
input is not under effective thermostatic control, unless additional and appropriate safety measures
are installed, SHOULD NOT be used. The boiler used can either be a sealed system or open vented
type, maximum primary circuit pressure 3 bar. The primary flow from the boiler MUST be pumped.
Gravity circulation will not work due to the special design of the primary heat exchanger. It is recom-
mended that an air bleed point or automatic air vent is incorporated in the primary return pipe work
close to the Megaflo
Commercial unit. The boiler flow temperature should usually be set to 82ºC
(maximum flow temperature to primary heat exchanger 89ºC). The boiler cannot be vented through
the Megaflo
Commercial unit.
Indirect Thermal Cut-Out And 2-Port Motorised Valve
To comply with Building Regulations, and to prevent the Megaflo Commercial from overheating the
2-port motorised valve supplied MUST be fitted to the primary flow to the indirect coil. It must be
wired such that in the event of the cylinder over heating it will close the primary circuit.
Wiring
All electrical wiring should be carried out by a competent electrician and be in accordance with the
latest I.E.E. Wiring Regulations BS 7671.
IT IS RECOMMENDED THAT ALL WIRING TO THE IMMERSION HEATERS IS OF A FIXED TYPE.
DO NOT OPERATE THE IMMERSION HEATER(S) UNTIL THE Megaflo COMMERCIAL HAS BEEN
FILLED WITH WATER.
Safety
DO NOT BYPASS THE THERMAL CUT-OUT(S) IN ANY CIRCUMSTANCES
DISCONNECT FROM THE MAINS SUPPLY BEFORE REMOVING ANY COVERS
NEVER ATTEMPT TO REPLACE AN IMMERSION HEATER OTHER THAN WITH THE
RECOMMENDED HEATRAE SADIA Megaflo COMMERCIAL SPARE PART
Temperature control
clockwise to increase,
counter-clockwise to
decrease
Thermal cut-out
reset under cap
0
30
40
50
60
70
°C
Figure 12: Indirect controls