- Heat pumps
- Air-to-water heat pump
E19
Viessmann E19 on a Vitocal heat pump: electric heater overload
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
On the Vitocal 100-AW, E19 means the electric heater overload protection has tripped, usually because of missing water or low flow. Read the circuit pressure, make sure any valve that was shut has been reopened, and call the technician if the code comes back.
Safety first
Stop and check this first
- Never bypass protections or add jumpers to get the heater working again: E19 is there to stop it overheating without water.
- The unit has several power circuits and some boards stay live after switch off; Viessmann tells the technician to wait 4 minutes and secure the system against being switched back on.
Safe checks you can perform
- Read the water circuit pressure
- Check any shut off valves that were closed
- Note when the heater runs and acknowledge the code
Leave these tasks to a qualified professional
- Do not attempt this professional task: Confirm water and flow in the circuit
- Do not attempt this professional task: Test the overload switch and the jumper
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Confirm water and flow in the circuit
What they doThe technician confirms the system is full and free of air, the pump runs, the valves are open and the circuit filter is clean, following Viessmann's water flow protection steps.
They must show youthe circuit pressure and the state of the pump, air vent and filter.
In writingwhat restricted the flow and what was corrected.
Test the overload switch and the jumper
What they doWith the unit isolated, the technician checks whether the protection switch is closed at standstill, inspects its wiring and the terminal strip jumper, and replaces the switch or the heater assembly if needed.
They must show youthe standstill test of the switch and the condition of the wiring.
In writingwhether the switch or heater was replaced, with part number and reason.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Read the water circuit pressure
- Who:
- you, no tools needed.
- How:
- if your system has a visible gauge, read it. Viessmann gives a minimum operating pressure of 8 PSI (0.5 bar) and a maximum of 30 PSI (2 bar) for this unit. Do not refill the circuit yourself: this model's manual does not treat that as an owner task.
- Result that matters:
- knowing whether the circuit holds enough water and pressure.
- If pressure is under 0.5 bar:
- call the technician and give the reading, as it fits a heater with no load.
- If pressure is normal:
- suspicion moves to the flow or the protection switch.
- Evidence to keep:
- photo of the gauge and of the screen with the code.
Evidence: Viessmann Vitocal 100-AW AM2V installation, service and operating instructions 6221389-11
Check any shut off valves that were closed
- Who:
- you, only with valves you can see.
- How:
- think about whether someone recently closed a valve on the heating pipes, for instance to change a radiator. Look at its position. Viessmann includes valves that are not fully open among the reasons for low flow.
- Result that matters:
- ruling out a valve left half closed.
- If you find a valve that was shut and never reopened:
- reopen it and watch whether E19 goes away.
- If you do not know what a valve does or all look open:
- leave them and tell the technician.
- Evidence to keep:
- photo of the valves and their positions.
Evidence: Viessmann Vitocal 100-AW AM2V installation, service and operating instructions 6221389-11
Note when the heater runs and acknowledge the code
- Who:
- you.
- How:
- read and confirm the notification on the controller. Check in the settings whether additional electric heating is switched on for space heating or hot water, an option the owner section mentions, and note whether E19 appears on very cold days or while heating water.
- Result that matters:
- information about the situation in which the protection trips.
- If it only appears when the backup heating is active:
- report it, as that narrows the diagnosis.
- If E19 shows up at random times:
- the technician should check flow and the switch from the start.
- Evidence to keep:
- a note with dates, outdoor temperature and active settings.
Evidence: Viessmann Vitocal 100-AW AM2V installation, service and operating instructions 6221389-11
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Heat pumps
- Brand
- Viessmann
- Product type
- Air-to-water heat pump
Known code variants
- 19
- aerotermia Viessmann E19
- Balay dishwasher E19
- Balay E19
- Baxi 19
- Baxi boiler E19
- Baxi code 19
- Baxi E 19
- Baxi E19
- Bosch dishwasher E19
- Bosch E19
- Bosch E19 error
- Bosch E19 lavavajillas
- Bosch Geschirrspüler Fehler E19
- code erreur E19 lave-vaisselle Bosch
- code erreur E19 lave-vaisselle Siemens
- codice E19 Siemens
- código E19 Bosch
- código E19 Siemens
- E19
- E19 Bosch dishwasher
- E19 lavavajillas Balay
- E19 Siemens dishwasher
- E:19
- erreur E19 Bosch
- erreur E19 Siemens
- Error 19 Baxi
- Error E19 Balay
- error E19 lavavajillas Bosch
- error E19 lavavajillas Siemens
- errore E19 lavastoviglie Siemens
- F19
- F:19
- Fehlercode E19 Bosch
- Fehlercode E19 Siemens
- Platinum Compact ECO 19
- Platinum Compact ECO E19
- Siemens dishwasher E19
- Siemens E19
- Siemens Geschirrspüler Fehler E19
- Viessmann air to water E19
- Viessmann bomba de calor E19
- Viessmann E19
- Viessmann heat pump E19
- Viessmann Vitocal 100-AW E19
- Vitocal 100-AW AM2V E19
- Vitocal backup heater E19
- Vitocal E19
- Vitocal electric heating overload
- Vitocal resistencia eléctrica E19
What it means
In the outdoor unit fault table of the Vitocal 100-AW AM2V manual (Viessmann, 02/2026, North American English edition), E19 is Electric heating overload protection. Viessmann gives four causes: the electric heater running with no water load, insufficient water flow, a badly connected or damaged overload protection switch, and a wrong jumper on its terminal strip. Diagnosis starts by confirming there is water and that it moves. The code is not enough to say the heater element has burnt out; those earlier checks come first.
Warnings and stop conditions
- Loweditorial warning
Never bypass protections or add jumpers to get the heater working again: E19 is there to stop it overheating without water.
Evidence: Viessmann Vitocal 100-AW AM2V installation, service and operating instructions 6221389-11
- Mediumsource verified
The unit has several power circuits and some boards stay live after switch off; Viessmann tells the technician to wait 4 minutes and secure the system against being switched back on.
Evidence: Viessmann Vitocal 100-AW AM2V installation, service and operating instructions 6221389-11
Symptoms and causes
Probable causes · in order
- Heater running with no waterCommon
The first cause is the electric heater working without load; the technician first checks that the system is actually full of water.
Evidence: Viessmann Vitocal 100-AW AM2V installation, service and operating instructions 6221389-11
- Too little water flowCommon
With weak flow the heat is not carried away; Viessmann refers to the water flow protection steps covering the pump, trapped air, circuit resistance, valves and the filter.
Evidence: Viessmann Vitocal 100-AW AM2V installation, service and operating instructions 6221389-11
- Overload switch damaged or badly wiredPossible
If the protection switch is open at standstill, the technician checks its connection; if the wiring is fine and it stays open, the switch itself is damaged.
Evidence: Viessmann Vitocal 100-AW AM2V installation, service and operating instructions 6221389-11
- Wrong jumper on the terminal stripLess common
The manual lists a false connection of the jumper on the heater overload protection terminal strip as a separate cause.
Evidence: Viessmann Vitocal 100-AW AM2V installation, service and operating instructions 6221389-11
Virtual technician
Does E19 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
Viessmann Vitocal 100-AW AM2V installation, service and operating instructions 6221389-11
Viessmann · 2026 · manual
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