E911 And My Units Keep Stopping - Samsung RC090MHXEA Service Manual

E911 and my units keep stopping

E911 is a simple fault; the flow speed through
the unit is not high enough. You should have a
flow meter installed, if you haven't now is the
time to buy one.
If you look into the flow meter you can see the
flow in litres per minute.
In this picture you can see a flow rate
indicated, this shows 25l/min NOT 35l/min
The flow switch trips out at 15l/min, if the flow drops below this E911 shows.
The main causes of E911 are:
Air in the system, you will need to get this out by venting the
air. To clear Air in the system, its best to run the pump for a
while to clear this, the best way to do this is use test mode to
run it permanently, clear the air and when finished begin the
commissioning process.
We have found that getting the air out of the system is
difficult, normal auto air vents don't seem to work as the
water speed is high. We recommend using a de-aerator,
Spiro vent do one.
The flow switch too close to a pump, bend or valve, the flow switch should be at least 150mm
from any other fitting.
The flow switch can be turned round by loosening the red nut, make sure
it's the right way round.
When the unit switches from heating to HW mode or back again you can
see E911 occur, it's particularly common on systems with 3 port valves.
NOTE if E911 occurs the unit will stop operating, it also clears the run
signals from external room thermostats and the hot water cylinder, both the
sun signal and tap signal will disappear. After 15 mins E911 will also
disappear making it look like the unit has been switched off.
It needs an engineer to look into the problem.
Flow switch test continuity see E912
If you think the flow switch is not operating correctly you can do a continuity test, you must
unplug the flow switch to test it. There should be continuity when the flow switch is made.
www.freedomhp.co.uk
If there is air in the system it trips the switch, hold the
top of the flow switch, you can actually feel the paddle
moving back and forward and hear it rattling.
To make life easier if you wind the flow meter into the
flow switch, this reduces the sensitivity of the flow
switch making E911 less likely.
©G Hendra Nov 18 51