HIUs

Training

Module 10

The objective for training in Part 10 is an in-depth look at error codes

Error Codes displayed on the controller screen

IMPORTANT These codes are NOT indicating an issue with the HIU, but an operational setting or possible network supply issue is the problem. This is an important function to help the service engineer diagnose the problem quickly.

Connection cable and wiring connection

Temperature sensor position and reference as used in this training module

RED = Primary FLOW  t11 
BLUE = Primary RETURN  t12
ORANGE =  Hot Water OUT  t32
WHITE = Heating FLOW  t22
GREY = Heating RETURN  t21

e1

Scope of E1 warning alert: to notify that the primary temperature is lower of temperature set point (t11 < t21 or t11<t32)

  • E1  never blocks the HIU operation
  • E1 temporarily disabled for 10 min the booster function
  • With E1 displayed ON the HIU normal operating conditions are guaranteed
  • E1 will be automatically cleared after 10 min
  • E1 can be cleared before its watching time (10 min) switching OFF the controller by ON/OFF bottom

How does E1 operates?

When E1 is displayed ON the booster function is temporarily disabled to avoid for safety reason any temperature overshoot

conditions due to rapidly increase of the primary temperature (t11)

Which operating conditions could activate E1?

  • During booster function: if the primary temperature t11 doesn’t increase of 1°C in minimum 5s è E1 is displayed
  • During tapping:  if after 60s of continues tapping t11 is  < t32 è E1 is displayed
  • During heating: if after 8 min (480s) with heating ON t11 is  < t21 è E1 is displayed

Booster: fully opens the PICV to rapidly increase the incoming temperature

e2

Scope of E2 warning alert: to notify that the primary return temperature is higher than the parameter 20 setting for maximum primary return temperature.  (t12 > Parameter 20 setting, factory set at 60C)

  • E2 closes the PICV stopping primary flow heat flow to the HIU (no central heating no DHW)
  • E2 HTG pump is OFF
  • Automatically cleared after 10 minutes (HIU back in normal operation mode)
  • Cleared if the primary return temperature drops 10C below the parameter 20 setting (all HTG, DHW and KWM conditions)

How does E2 operates?

E2 closes the PICV stopping primary flow heat flow to the HIU (no central heating no DHW)

E2 HTG pump is OFF

Which operating conditions could activate E2?

DHW:

  • If after 3 minutes of constant tapping t12 > maximum primary return temperature (Parameter 20)
  • Automatically cleared after 10 minutes (HIU back in normal operation mode)
  • Cleared if the primary return temperature drops 10C below the parameter 20 setting (watching time 30s)

Central Heating:

  • If after 3 minutes of constant heating demand t12 > maximum primary return temperature (Parameter 20)
  • Automatically cleared after 10 minutes (HIU back in normal operation mode)
  • Cleared if the primary return temperature drops 10C below the parameter 20 setting (watching time 30s)

Stand-by Keep Warm (if active) 

  • If after 3 minutes of keep warm operating t12 > maximum primary return temperature (Parameter 20)
  • Automatically cleared after 10 minutes (HIU back in normal operation mode)
  • Cleared if the primary return temperature drops 10C below the parameter 20 setting (watching time 30s)

E2 override can be achieved by increasing the Parameter 20 setting to its maximum or set the Parameter 20 to 5C higher than the Heating FLOW temperature.

E2 could activated from a too higher HTG conditions, with unbalancing TRVs and radiators,  wrong set on the rooms

Dynamic pre-setting TRVs are recommended to mitigate or eliminate these issues

e3

Scope of E3 warning alert: to notify that the PHE is under performing

  • With E3 displayed ON the HIU still operating but in a underperforming conditions.

How does E3 operates?

E3 notice to the user that the HIU is underperforming but not limit its operating functions.

The algorithm displayed E3 if the working point is shifted of 50% from its nominal working condition.

Which operating conditions could activate E3?

DHW:

  • Excess of limescale deposit into the DHW plate heat exchanger
  • Automatically cleared after 10 minutes if normal operating performances and conditions will be detected by the controller

Central Heating:

  • Pure quality of central heating medium which could slowly block both HTG pump and plate heat exchanger
  • Automatically cleared after 10 minutes if normal operating performances and conditions will be detected by the controller

Is recommended to fit both limescale and magnetic filter

E4

Scope of E4 warning alert: to notify that DHW temperature sensor is disconnected from the pipe or is fitted in a wrong position or is broken

  • E4 disabled DHW function from safety reason (risk of scald)

How does E4 operates?
Hot water temperature control is not accurate.

Which operating conditions could activate E4?

  • Any conditions where t12>t32
  • Check the DHW sensor is in the correct position.
  • Then system reset, turn off the power at the supply, and then turn on again to allow the PICV actuator to re-calibrate its position.
  • Check movement of the diverter valve, is the actuator moving? Take the actuator off to check if the valve is jammed.

In case E4 will be displayed check first the DHW sensor position, add heating paste to helps the reading

 

E5

Scope of E5 warning alert: to notify that the heating temperature has not reached the set point as expected after a reasonable time (t22 < parameter 9 set point for radiators or t22 < parameter 8 set point for underfloor heating.

  • E5 is displayed if heating is not reaching the set point so is performing poorly or not at all.

How does E5 operates?

If the heating set is not reached even if t11 > t21 PICV shuts, and controller displays E5.

Watching time: 20 minutes when programmed for radiators, 60 minutes when programmed for UFH systems

Which operating conditions could activate E5?

  • Unbalancing radiators
  • Wrong set or broken room-stat
  • E5 automatically cleared after 30s
  • Check movement of the diverter valve, is the actuator moving? Take the actuator off to check if the valve is jammed.

In case E5 will be displayed check heating set, room-stat and TRVs head set

E6

Scope of E6 warning alert: to notify that the heating temperature sensor is disconnected from the pipe or is fitted in a wrong position or is broken

  • E6 is displayed if temperature information from the heating temperature sensors is wrong or unusual.

How does E6 operates?

In case t12 > t11 E6 is displayed to notice the unusual HIU operation

Which operating conditions could activate E6?

  • Anomalous heat transfer from the secondary to primary (additional heat source)
  • Swap between supply and return temperature sensor
  • Automatically cleared after 10 minutes

In case E6 will be displayed check correct supply and return temperature sensor position / wiring into the controller

E7

Scope of E7 warning alert: to notify that the central heating gradient is too high

  • E7 is displayed to notice the user/operator that heating return temperature is too high

How does E7 operates?

In case t22 > the setting for parameter 20 (the maximum primary temperature limit), controller shuts the HTG pump

Which operating conditions could activate E7?

  • Gradient return heating temperature too high due to drastically heating load change (e.g. only small radiator operates from a scenario where full load were demanded).
  • E7 automatically cleared after 30s

Balance heating system and replace traditional TRVs with dynamic presetting TRV.

E8

Scope of E8 warning alert: to detect temperature overshooting reducing the risk of scald

  • E8 is displayed to notice that PICV shuts rapidly after a watching time of 90s + Kx10s (K =0….21 param 69) in a event of DHW supply T overshooting (10°C higher the set temperature). Same monitoring (diagnostics recording purpose) also in CH but the PICV doesn’t shut.

How does E8 operates?

  • When E8 is displayed PICV is closed for for 3 times unless a manual reset in each of the single period if the temperature detected is within the bandwidth (set + 10°C) E8 is automatically cleared. Manual reset is needed after 3 times of automatically error clearing. Manual reset always however available

Which operating conditions could activate E8?

  • In case that TRVs rapidly shuts with energy increase into the heating  PHE  and if tap water is called diverting valve diverts resulting in the supply DHW T overshooting above 10°C to the set

End of Module 10

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