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--- ve.bus:ve.bus_error_codes [2019-02-14 10:16] – martijncoster
+++ ve.bus:ve.bus_error_codes [2019-02-14 20:45] – [Error 24 - Sw simonhackett
@@ Line 151: / Line 151: @@
   - There is too much AC load connected at the moment the relay needs to switch off. This large current will prevent the relay contacts from opening.\\ \\ Solution: remove excessive load. \\ \\
   - The AC input voltage slowly drops before it is being rejected by the Multis. Typically happens in installations with a genset. Especially when combined with AC loads that increase their current draw when the AC voltage drops: at the moment the Multis or Quattros decide to switch off, the current through the relays is too high to open them.\\ \\ Solution: Make the Multis or Quattros disconnect earlier: increase lower limit of AC input voltage in VEConfigure3. For example to 210 VAC. The factory setting is 180 VAC. \\ \\
-  - The back-feed relay has a hardware failure (and is stuck 'on')\\ \\ Solution: Replace faulty unit.
+  - The back-feed relay has a hardware failure \\ \\ Solution: Replace faulty unit.
 __Diagnostic notes for systems showing error 24 where a stuck 'on' relay is suspected__
-In a single unit system, turn the unit 'off' on the front panel rocker switch and apply AC input power. Measure the AC output. If AC voltage is present, the unit is faulty (stuck relay).
+In a single phase installation with two or more devices in parallel, or a three-phase installation with six or more devices, it can be difficult to identify the unit that is faulty because all units in at the relevant group of units will raise 'Error 24'.
-In a three-unit, three-phase cluster (only one unit per phase), the faulty unit can be identified in the same way. As for the single unit case, any unit presenting AC output voltage when the rocker switch is set to 'off' is faulty.
+This happens because the faulty unit will be (incorrectly) supplying AC energy on it output at times when it should not be - including when its front panel rocker switch is set to 'off', When energy from the faulty unit's AC output flows in to the other unit(s) via their AC outputs, this causes these other units to be (incorrectly) flagged for 'Error 24' by the system self-test. The units concerned may also be 'buzzing' in the presence of AC power at their inputs with their rocker switches set 'off'.
-You can also determine the faulty unit(s) by just listening for units that are //audibly humming// while their front panel rocker switch is set 'off'. The humming is because AC power is being applied to the internal circuitry when it should not be.
+To help identify which unit is faulty in this scenario, first un-wire the AC outputs of all the units concerned to prevent cross-feeding of AC energy via the AC outputs. Then apply AC power with all units still set to 'off' on their front panel rocker switches. Measure the AC output terminals with a meter - the faulty unit is the one that is still presenting AC voltage on its output terminals. If this approach is not successful, try turn turning the units 'On' and look for which unit now presents 'Error 24' in isolation.
-Where there are multiple units hardwired in parallel (a multi-unit/single phase system, or a three-phase cluster with 6 or more units), then there is an additional diagnostic challenge. In these systems, the faulty unit will be feeding energy out from its AC output and this energy will then flow into to the other (good) units via their respective AC output terminals. This results in //all// units that are parallel-wired appearing to be faulty, and all units concerned humming while set to 'off'.
+If this is not conclusive, try completely disconnecting all suspect units from all AC and DC sources. With an ohm-meter, measure the resistance between the neutral terminals on AC input and the AC output, A working unit will show no connection between these terminals. A faulty unit may show a connection to be present between these terminals, with either zero resistance or potentially with a small a non-zero (and non-normal) resistance present.
-The most conclusive way to determine which unit is faulty in this case is to un-wire the AC outputs of all the units concerned to prevent the cross-feeding of AC energy via the AC outputs. Then apply AC power with all units still set to 'off' on their front panel rocker switches. The faulty unit is the one that is still humming and that is still presenting AC voltage on its output terminals.
 ==== Error 25 - Firmware incompatibility ====
 Make sure to use the same firmware in all devices.