Vaillant fault code F.1100
Fault code F.1100 on a Vaillant heat pump (including aroTHERM split and aroTHERM split uniTOWER) means: The safety temperature limiter of the electric auxiliary heater has opened due to: flow rate too low or air in the emitter circuit, heating element in operation with emitter circuit not filled, heating element in operation at flow temperatures above 95°C causes the thermal fuse of the safety temperature limiter to blow and requires replacement, supply of external heat into the ambient circuit. Reset the appliance once. If the code comes back, a part is usually faulty.
After a safety alert (gas, flue gas, combustion), reset no more than once and call in a certified gas engineer. If you smell gas, call your national gas emergency number or 112 immediately.
Cause
Fault code F.1100 on a Vaillant heat pump indicates: The safety temperature limiter of the electric auxiliary heater has opened due to: flow rate too low or air in the emitter circuit, heating element in operation with emitter circuit not filled, heating element in operation at flow temperatures above 95°C causes the thermal fuse of the safety temperature limiter to blow and requires replacement, supply of external heat into the ambient circuit.
Applies to
Vaillant aroTHERM split, aroTHERM split uniTOWER, VWL 127 5 IS _ VWL 105 5 AS, VWL 127 5 IS _ VWL 125 5 AS, VWL 128 5 IS _ VWL 105 5 AS, VWL 128 5 IS _ VWL 125 5 AS, VWL 57 5 IS _ VWL 35 5 AS, VWL 57 5 IS _ VWL 55 5 AS, VWL 58 5 IS _ VWL 35 5 AS, VWL 58 5 IS _ VWL 55 5 AS.
Fault code F.1100 on other Vaillant series
The same code does not mean the same thing on every series. Check the rating plate to see which series you have:
- F.1100 on flexoCOMPACT exclusive, VWF 118/4, VWF 88/4: The safety temperature limiter of the electric auxiliary heater has opened due to: flow rate too low or air in the emitter circuit, heating element in operation with emitter circuit not filled, heating element in operation at flow temperatures above 110°C causes the thermal fuse of the safety temperature limiter to blow and requires replacement, supply of external heat into the ambient circuit.
- F.1100 on flexoTHERM, VWF 117/4, VWF 157/4, VWF 197/4, VWF 57 /4, VWF 87/4: The safety temperature limiter of the electric auxiliary heater has opened due to: flow rate too low or air in the emitter circuit and/or heating element in operation with emitter circuit not filled and/or thermal fuse of the safety temperature limiter blown and requires replacement and/or supply of external heat into the ambient circuit.
- F.1100 on Hydraulisch station, VWZ MEH 97/6 w _ VWL 35_6 A 230V, VWZ MEH 97_6 w _ VWL 105_6 A, VWZ MEH 97_6 w _ VWL 125_6 A, VWZ MEH 97_6 w _ VWL 55_6 A 230V, VWZ MEH 97_6 w _ VWL 65_6 A 230V: The safety temperature limiter of the electric auxiliary heater has opened due to: flow rate too low or air in the emitter circuit, heating element in operation with emitter circuit not filled, heating element in operation at flow temperatures above 98°C causes the thermal fuse of the safety temperature limiter to blow and requires replacement, supply of external heat into the ambient circuit.
- F.1100 on uniTOWER pure, VWL 107 7.2 IS S1 _ VWL 105 7.2 AS 230V S3, VWL 107 7.2 IS S1 _ VWL 45 7.2 AS 230V S3, VWL 107 7.2 IS S1 _ VWL 65 7.2 AS 230V S3, VWL 107 7.2 IS S1 _ VWL 85 7.2 AS 230V S3, VWL 107 7.2 IS _ VWL 105 7.2 AS 230V S3: The safety temperature limiter of the electric backup heater has opened due to: – insufficient flow rate or air in the heat emission circuit, – operation of the electric heating element with the heat emission circuit not filled, – operation of the electric heating element at flow temperatures above 95 °C activates the thermal fuse of the safety temperature limiter and requires replacement, – supply of external heat into the heat emission circuit.
Matching parts
Vaillant parts are available from Instalpunt; shipping to EU countries from €17.95 (€24.95 for more distant countries), usually 3–5 working days.
Parts by Vaillant series: ecoTEC plus · ecoTEC pro.
This message does not point directly to one faulty part. These are the parts that most often fit this appliance:
- Vaillant temperature sensor € 31.36
- Vaillant sealing ring set of 3 pcs € 13.07
- Vaillant sensor for e.g. aroTHERM Pro VWL 75/7.1 A 230V 0020269357 € 20.26
Fix it yourself or call an engineer?
Always consult the manual for your appliance and work safely. If in doubt or if the fault comes back, call in a qualified professional. A question about a part? Write to us at info@instalpunt.nl.
Frequently asked questions
What does Vaillant heat pump fault code F.1100 mean?
The safety temperature limiter of the electric auxiliary heater has opened due to: flow rate too low or air in the emitter circuit, heating element in operation with emitter circuit not filled, heating element in operation at flow temperatures above 95°C causes the thermal fuse of the safety temperature limiter to blow and requires replacement, supply of external heat into the ambient circuit.
How do I fix fault code F.1100 on a Vaillant heat pump?
First check the cause described above. Then restart the appliance using the reset button. If the message comes back, a part usually needs replacing or the fault needs to be repaired by a qualified professional.
Which parts do I need for Vaillant fault code F.1100?
That depends on the exact cause. In the Vaillant parts overview at Instalpunt you will find the current price and stock for each part.
Can I fix fault code F.1100 myself?
You can reset the appliance and check things like the water pressure or settings yourself. Work on gas-carrying parts must be left to a certified gas engineer.
All Vaillant heat pump faults and codes at a glance →