Troubleshooting Xylem (Until 2014)
* In the event of overheating, the pump automatically
reduces the voltage (the speed) at 105°C, stopping
completely at 125°C. When the pump has cooled to
115°C again, it restarts automatically.
Control signal:
The control signal is a direct current voltage to the pump.
Depending on which instrument is used to measure the
voltage, there can be deviations from these values.
May be due toDescriptionLED colour
Low voltage.Low voltage.1 short + 1
long flash
Low flow
Automatic reset.
High temperature.3 short + 1
long flash
Pump blocked.Pump blocked.5 short + 1
long flash
No power to the
pump.
Is the air pump
working?
Electronics dam-
aged; replace pump.
The pump does not
have power.
LED damaged.
The electronics do
not work.
No LED
Other faults:
ActionCauseProblem
- Vent the system.Air in the system.Noise from pump.
- Open and clean
the pump.
Dirt in the pump.
- Replace the
pump.
Worn bearings.
Function check, components
NIBE SPLIT ACVM270 Relay test - forced
control
Control conditions
Forced control of the relays can be carried out in menu
9.3.7.0. Menu 9.3.7.1 must be selected to ”On” in order
for the function to be activated. Respective relay con-
trolled by selecting 0, 1 or dash (-) for each relay in menu
9.3.7.2 to 9.3.7.15.
0 is not powered -inactive, 1 is voltage out -active, and
(-) means "Auto", i.e. the control system selects whether
the output is active or inactive.
WARNING!
Forced control must only be used by users fa-
miliar with the system. When forced control is
activated, the alarm functions are disabled.
Testing shunts
Relay 2 and 3 are connected in series and used to control
Three-way valve Cooling/heating.
Relays K5 and K4 are used to open and close mixing valve
QN11. Therefore, relays K4 and K5 must not be set to
mode 1 at the same time.
To open the mixing valve, select relay K4 to position 1
and relay K5 to position 0.
To close the mixing valve, select relay K5 to position 1
and relay K4 to position 0.
The mixing valve is locked when K4 and K5 are in position
0.
Relays K13 and K14 are used to open and close mixing
valve 2. Therefore, relays K14 and K13 must not be set
to mode 1 at the same time.
To open the mixing valve, select relay K13 to position 1
and relay K14 to position 0.
To close the mixing valve, select relay K14 to position 1
and relay K13 to position 0.
The mixing valve is locked when K14 and K13 are in po-
sition 0.
55Chapter 5 | TroubleshootingNIBE SPLIT ACVM270
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