Vaillant
Vaillant Flow Sensor Complete Black 178988
Vaillant complete black flow sensor (178988) for Ecotec VUI and VUW condensing boilers, reading circuit resistance to control boiler heat output.
At a glance
- Also known as 1376548, N6443
Showing prices
£40.42
£33.68 ex. VAT · VAT at 20%
Available to order · 3 working days
Available to order · 3 working days
Not certain it's the right part? The technical team verifies fitment before dispatch — no charge, and it stops a second trip.Call the technical teamSend a technical question
Same-day dispatch
Ordered by 4pm Mon–Fri, 10:30am Sat.
30-day returns
Unused, in original packaging.
What it is
The Vaillant flow sensor, part number 178988, is a complete black sensor assembly fitted to Vaillant condensing boilers. It sits in the water circuit and works as a thermistor: as the temperature rises, its resistance falls in line with the circuit. The boiler's printed control board feeds a current through the sensor and reads the relative resistance, using that reading to decide whether the appliance needs to increase or decrease heat output.
Signs this part needs replacing
- Domestic hot water temperature swings between hot and cold instead of holding steady
- The boiler fails to modulate correctly and runs at a fixed output
- Heating or hot water demand is not recognised, so the appliance does not fire
- The control board reports a sensor or flow fault
- Resistance readings from the sensor do not change as expected when the circuit warms up
Before you order
- Check the GC number on the appliance data badge against the compatibility list to confirm the correct variant
- Confirm the part number on the existing sensor matches 178988 before ordering
- Cross-check the alternative numbers 1376548 and N6443 if the original marking is unclear
Mechanical
| Part type | Flow Sensor |
|---|
Compliance
| Manufacturer part number (MPN) | 178988 |
|---|---|
| Barcode / EAN | 4024074477670 |
| Commodity code | 8533 40 10 00 |
| GPC classification | Household Boilers/Furnaces/Tank Water Heaters Replacement Parts/Accessories |
| Alternative numbers | 4024074146750, VAILLANT178988, 17-8988, VAILLANT178988, VAILLANT178988, VAILLANT178988, 1376548, N6443 |
| Make | Model / assembly | Reference | Years | Fitment |
|---|---|---|---|---|
| VAILLANT VAILLANT ECOTEC EXCLUSIVE 832 - VUW 326/4 | — | — | — | |
| VAILLANT VAILLANT ECOTEC EXCLUSIVE 838 - VUW 386/4 | — | — | — | |
| VAILLANT VAILLANT ECOTEC PLUS 824 - VUW 246/3-5 | — | — | — | |
| VAILLANT VAILLANT ECOTEC PLUS 824 - VUW 246/3-5 R1 | — | — | — | |
| VAILLANT VAILLANT ECOTEC PLUS 824 - VUW 246/3-5 R3 | — | — | — | |
| VAILLANT VAILLANT ECOTEC PLUS 824 - VUW 246/5-5 | — | — | — | |
| VAILLANT VAILLANT ECOTEC PLUS 824 - VUW 246/5-5 R1 | — | — | — | |
| VAILLANT VAILLANT ECOTEC PLUS 824 - VUW 246/5-5 R2 | — | — | — | |
| VAILLANT VAILLANT ECOTEC PLUS 831 - VUW 316/3-5 | — | — | — | |
| VAILLANT VAILLANT ECOTEC PLUS 831 - VUW 316/3-5 R1 | — | — | — |
Showing 10 of 180 compatible appliances.
Fitment listings are a guide, not a guarantee. Plant-room assemblies get modified on site more often than not. Send us the GC number off the data badge and a photo of the existing valve and we will confirm before anything is dispatched.
Documents & drawings
Everything we hold for this part. Where a document exists but we don't hold it, the technical team will source it from the manufacturer — usually the same working day.
manual
VAILLANT appliance manual — VUI 376/3-5 (GC 47-044-39), ecoTEC 937 VUI 376/3-5 (2006-2012) (GC 47-044-39)
manualmanualVAILLANT appliance manual — VUW 196/5-5 R6 (GC 47-044-83), VUW 246/5-5 R6 (GC 47-044-84), VUW 246/5-5 R6 LPG (GC 47-044-85), VUW 286/5-5 R6 (GC 47-044-86), VUW 306/5-5 R6 (GC 47-044-82), ecoTEC PLUS 825 VUW 196/5-5 R6 (2017) (GC 47-044-83), ecoTEC PLUS 832 VUW 246/5-5 R6 (2017) (GC 47-044-84), ecoTEC PLUS 832 VUW 246/5-5 R6 LPG (2017) (GC 47-044-85), ecoTEC PLUS 835 VUW 306/5-5 R6 (2017) (GC 47-044-82), ecoTEC PLUS 838 VUW 286/5-5 R6 (2017) (GC 47-044-86)
manualmanualVAILLANT appliance manual — VUW 246/3-3 R1 (GC 47-044-36), VUW 246/3-3 R2 (GC 47-044-36), VUW 246/3-5 (GC 47-044-31), VUW 246/3-5 R1 (GC 47-044-31), VUW 246/3-5 R3 (GC 47-044-31), VUW 286/3-3 (GC 47-044-30), VUW 286/3-3 R1 (GC 47-044-30), VUW 286/3-3 R2 (GC 47-044-30), VUW 316/3-5 (GC 47-044-32), VUW 316/3-5 R1 (GC 47-044-32), VUW 316/3-5 R3 (GC 47-044-32), VUW 316/3-5 R5 (GC 47-044-32), VUW 376/3-5 (GC 47-044-33), VUW 376/3-5 R1 (GC 47-044-33), ecoTEC PLUS 824 VUW 246/3-5 (2005-2005) (GC 47-044-31), ecoTEC PLUS 824 VUW 246/3-5 R1 (2005-2006) (GC 47-044-31), ecoTEC PLUS 824 VUW 246/3-5 R3 (2011-2012) (GC 47-044-31), ecoTEC PLUS 831 VUW 316/3-5 (2005-2005) (GC 47-044-32), ecoTEC PLUS 831 VUW 316/3-5 R1 (2005-2006) (GC 47-044-32), ecoTEC PLUS 831 VUW 316/3-5 R3 (2011-2012) (GC 47-044-32), ecoTEC PLUS 831 VUW 316/3-5 R5 (2013 - 2013) (GC 47-044-32), ecoTEC PLUS 837 VUW 376/3-5 (2005-2005) (GC 47-044-33), ecoTEC PLUS 837 VUW 376/3-5 R1 (2005-2006) (GC 47-044-33), ecoTEC PRO 24 VUW 246/3-3 R1 (2005-2006) (GC 47-044-36), ecoTEC PRO 24 VUW 246/3-3 R2 (2008-2012) (GC 47-044-36), ecoTEC PRO 28 VUW 286/3-3 (2005-2006) (GC 47-044-30), ecoTEC PRO 28 VUW 286/3-3 R1 (2005-2006) (GC 47-044-30), ecoTEC PRO 28 VUW 286/3-3 R2 (GC 47-044-30)
manualmanualVAILLANT appliance manual — VUW 246/5-3 (GC 47-044-44), VUW 246/5-3 R1 (GC 47-044-44), VUW 246/5-3 R2 (GC 47-044-44), VUW 246/5-3 R4 (GC 47-044-44), VUW 286/5-3 (GC 47-044-45), VUW 286/5-3 R1 (GC 47-044-45), VUW 286/5-3 R2 (GC 47-044-45), VUW 286/5-3 R4 (GC 47-044-45), ecoTEC PRO 24 VUW 246/5-3 (2012-2012) (GC 47-044-44), ecoTEC PRO 24 VUW 246/5-3 R1 (2012-2013) (GC 47-044-44), ecoTEC PRO 24 VUW 246/5-3 R2 (2013-2015) (GC 47-044-44), ecoTEC PRO 24 VUW 246/5-3 R4 (2015-2015) (GC 47-044-44), ecoTEC PRO 28 VUW 286/5-3 (2012-2012) (GC 47-044-45), ecoTEC PRO 28 VUW 286/5-3 R1 (2012-2013) (GC 47-044-45), ecoTEC PRO 28 VUW 286/5-3 R2 (2013-2015) (GC 47-044-45), ecoTEC PRO 28 VUW 286/5-3 R4 (2015-2015) (GC 47-044-45)
manualmanualVAILLANT appliance manual — VUW 246/5-3 A R4 (GC 47-044-54), VUW 286/5-3 A R4 (GC 47-044-55), VUW 306/5-3 R4 (GC 47-044-52), ecoTEC PRO 24 VUW 246/5-3 A R4 (2015-2017) (GC 47-044-54), ecoTEC PRO 28 VUW 286/5-3 A R4 (2015-2017) (GC 47-044-55), ecoTEC PRO 30 VUW 306/5-3 R4 (2015) (GC 47-044-52)
manualmanualVAILLANT appliance manual — VUW 246/5-3 R6 (GC 47-044-88), VUW 286/5-3 R6 (GC 47-044-89), VUW 286/5-3 R6 LPG (GC 47-044-90), ecoTEC PRO 24 VUW 246/5-3 R6 (2017) (GC 47-044-88), ecoTEC PRO 28 VUW 286/5-3 R6 (2017) (GC 47-044-89), ecoTEC PRO 28 VUW 286/5-3 R6 LPG (2017) (GC 47-044-90)
manualmanualVAILLANT appliance manual — VUW 246/5-5 (GC 47-044-40), VUW 246/5-5 R1 (GC 47-044-40), VUW 246/5-5 R4 (GC 47-044-40), VUW 316/5-5 (GC 47-044-41), VUW 316/5-5 R1 (GC 47-044-41), VUW 316/5-5 R2 (GC 47-044-41), VUW 316/5-5 R4 (GC 47-044-41), VUW 376/5-5 (GC 47-044-42), VUW 376/5-5 R1 (GC 47-044-42), VUW 376/5-5 R2 (GC 47-044-42), VUW 376/5-5 R4 (GC 47-044-42), ecoTEC PLUS 824 VUW 246/5-5 (2012-2012) (GC 47-044-40), ecoTEC PLUS 824 VUW 246/5-5 R1 (2012-2013) (GC 47-044-40), ecoTEC PLUS 824 VUW 246/5-5 R4 (2015-2015) (GC 47-044-40), ecoTEC PLUS 831 VUW 316/5-5 (2012-2012) (GC 47-044-41), ecoTEC PLUS 831 VUW 316/5-5 R1 (2012-2013) (GC 47-044-41), ecoTEC PLUS 831 VUW 316/5-5 R2 (2013-2015) (GC 47-044-41), ecoTEC PLUS 831 VUW 316/5-5 R4 (2015-2015) (GC 47-044-41), ecoTEC PLUS 837 VUW 376/5-5 (2012-2012) (GC 47-044-42), ecoTEC PLUS 837 VUW 376/5-5 R1 (2012-2013) (GC 47-044-42), ecoTEC PLUS 837 VUW 376/5-5 R2 (2013-2014) (GC 47-044-42), ecoTEC PLUS 837 VUW 376/5-5 R4 (2015-2015) (GC 47-044-42)
manualmanualVAILLANT appliance manual — VUW 256/5-5 R4 (GC 47-044-57), VUW 326/5-5 R4 (GC 47-044-58), VUW 356/5-5 R4 (GC 47-044-53), VUW 386/5-5 R4 (GC 47-044-60), ecoTEC PLUS 825 VUW 256/5-5 R4 (2015) (GC 47-044-57), ecoTEC PLUS 832 VUW 326/5-5 R4 (2015) (GC 47-044-58), ecoTEC PLUS 835 VUW 356/5-5 R4 (2015) (GC 47-044-53), ecoTEC PLUS 838 VUW 386/5-5 R4 (2015) (GC 47-044-60)
manualmanualVAILLANT appliance manual — VUW 326/4-7 (GC 47-044-37), VUW 386/4-7 (GC 47-044-38), ecoTEC EXCLUSIVE 832 VUW 326/4-7 (GC 47-044-37), ecoTEC EXCLUSIVE 838 VUW 386/4-7 (GC 47-044-38)
manualmanualVAILLANT appliance manual — VUW 356/5-7 (GC 47-044-66), VUW 436/5-7 (GC 47-044-67), ecoTEC EXCLUSIVE 835 VUW 356/5-7 (2016) (GC 47-044-66), ecoTEC EXCLUSIVE 843 VUW 436/5-7 (2016) (GC 47-044-67)
manualmanualVAILLANT appliance manual — ecoTEC PLUS 940 VUI 30/40 CS/1-5 (2023) (GC 47-044-96)
manualNo technical questions yet for this part.
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