Heatrae Sadia Megalife 100E Installation Manual page 15

9.3 Fault Finding
The Fault Finding chart below will enable operational faults to be identified and their possible causes rectified. Any
work carried out on the Megalife water heater and its associated controls MUST be carried out by a competent installer
for water heating systems. In case of doubt contact the Heatrae Sadia Service Department (see back page).
Table 02: Fault Finding
FAULT
No hot water flow
Hot water flow gradually
decreases
Water from taps is cold
POSSIBLE CAUSE
1. No water in cold feed
cistern
2. Service valve in cold water
feed pipe from cistern turned
off
3. Air lock in system
4. Inadequate head between
outlet and cold water feed
cistern
1. Outlet flow rate exceeds
inlet flow to cold water feed
cistern
2. Flow starvation caused by
opening further outlets
1. DIRECT immersion heater
is not switched on
2. DIRECT immersion heater
thermal cut-out has operated
3. INDIRECT programmer set
to central heating only
4. INDIRECT boiler not
working
5. INDIRECT thermal cut-out
has operated
6. INDIRECT motorised valve
not connected correctly
REMEDY
1. Check water supply to cold
feed cistern
2. Turn on service valve
3. Check pipework layout for
possible air locking points,
rectify as necessary
4. Check minimum head
requirement of outlet fitting
1. Install higher flow float
valve. Consider larger cold
water cistern storage capacity
2. Check pipe sizings and
layout. Consider restricting
flow rate through lower taps
1. Check and switch on
2. Check, reset by pushing
button (see Fig 4, page 9)
3. Check, set to a domestic
hot water programme
4. Check boiler operation. If
fault is suspected consult
boiler manufacturer's
instructions
5. Check, reset by pushing
button on cut-out. Check
operation of indirect
thermostat
6. Check wiring and/or
plumbing connections to
motorised valve (see figs 5
& 6, page 10)
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