STIEBEL ELTRON DHE SL User manual

STIEBEL ELTRON
1
DHE SL
3 Phase electric fullyelectronic controlled
instantaneous hot water system
This unit electronically switches on via a
flow wheel at 2.5ltr/min
DHE 18 SL -18.0kW / 26amps per phase
DHE 21 SL -21.0kW / 31amps per phase
DHE 27 SL -27.0kW / 39amps per phase
3 Active phases & 1 Earth (no neutral)
Maximum 60oC
Minimum 20oC
M2 Memory button
Play “” button on the cover (menu button)
M1 memory button

Trouble Shooting DHE SL
2
1. Unit not heating…. water coming out the tap but no temperature rise on the
cold at all. Set unit to 60degC on front lcd display before proceeding
a. Has the unit been activated – Initial start up procedure followed?
•The small square activation button pushed in fully.
See page 29 “5.10” of instruction manual for start-up procedure. The lcd
display will not come on if not activated.
If activated proceed.
b. Check power to the unit – phase to earth = 230V, phase to phase =
400V
If yes proceed, if no rectify power issue.
c. Is there an “error” message on the front of the lcd display?
If there is an error on the display, remove cover and activate the service
mode button pg33 . Follow the instructions to determine the fault – an
error code will be displayed eg. “E1, E2, E3 or E4”
If no error message proceed.
d. Check to ensure the plumbing is correct.
•Cold supply to the right side of the unit and hot out on the left when
looking at it.
Water will flow backwards through the unit but will not activate the power
to heat the water. When in service mode the flow rate will indicate
approx 3.0ltr/min even though more flow is coming out of the hot tap
(this is a good indication pipe-work is back to front).
If pipe-work correct proceed.
e. With power off and cold water isolation valve turned off remove the
outlet pipe and fit a flexi to run into a bucket or floor drain. Open isolation
valve to run water through the unit and switch power on. Re-check to
see if unit is now operating.
If temperature correct, there is an issue with the plumbing after the hot
water system. Rectify plumbing and re-test.
If temperature still not correct – replace unit.

Trouble Shooting DHE SL
3
2. Unit only warm…. warm water only coming out of the tap, will not get hot.
Set unit to 60degC on front lcd display before proceeding
a. Is there an “error” message on the front of the lcd display?
If there is an error on the display, remove cover and activate the service
mode button pg33. Follow the instructions to determine the fault – an
error code will be displayed eg. “E3” = outlet sensor fault.
If no error message proceed.
b. Isolate the cold supply to the hot water unit and then open up the hot
tap.
•If a tempering valve is installed only a dribble of water should come
out of the outlet. If any greater than a dribble there is a fault with the
tempering valve or a cross connection.
Try adjusting the tempering valve to eliminate the water flow from the
hot tap to a minimum. Re-test hot water system.
•If no tempering valve installed there should be no flow of water from
the outlet. If water is still flowing there is a cross connection.
Eliminate cross connection if water is still flowing.
Proceed if no water flow.
c. With the power on to the unit, “tong” the 3ea active phases to measure
for amperage. When the unit is activated you should get a reading on all
phases – the amps will vary on the unit size and flow rate v’s
temperature setting on the unit.
If no amperage on 1 or more phases the element will need to be
replaced.
If amperage on all phases proceed.
d. With power off and cold water isolation valve turned off remove the
outlet pipe and fit a flexi to run into a bucket or floor drain. Open isolation
valve to run water through the unit and switch power on. Re-check to
see if unit is now operating.
If temperature correct, there is an issue with the plumbing after the hot
water system. Rectify plumbing and re-test.
If temperature still not correct – replace unit.

Trouble Shooting DHE SL
4
3. Unit fluctuating…. Unit fluctuating hot and cold when showering.
Set unit to 60degC on front lcd display before proceeding
a. Is there an “error” message on the front of the lcd display?
If there is an error on the display, remove cover and activate the service
mode button pg33. Follow the instructions to determine the fault – an
error code will be displayed eg. “E3” = outlet sensor fault.
If no error message proceed.
b. Is the unit installed with a tempering valve?
If yes proceed, if no go to “b”.
•Ensure the tempering valve is a high performance model suitable for
instant hot water units. If the wrong valve is installed the unit will
fluctuate.
If correct proceed.
c. Isolate the cold supply to the hot water unit and then open up the hot
tap.
•If a tempering valve is installed only a dribble of water should come
out of the outlet. If any greater than a dribble there is a fault with the
tempering valve or a cross connection.
Try adjusting the tempering valve to eliminate the water flow from the
hot tap to a minimum. Re-test hot water system.
If correct proceed.
d. Check shower head to remove any restrictors. Note all shower heads
now have a restrictor located in them somewhere to comply with
“WELS”. This MUST be removed as it may cause the unit to fluctuate.
If restrictor found, remove and re-test. Restrictors can cause back
pressure on the unit causing it to switch on and off.
If no restrictor proceed.
e. With power off and cold water isolation valve turned off remove the
outlet pipe and fit a flexi to run into a bucket or floor drain. Open isolation
valve to run water through the unit and switch power on. Check for
temperature fluctuations.
If no fluctuating occurs there is a restriction further down the hot
plumbing pipe-work. Rectify and re-test.
If unit is still fluctuating – replace.