Baxi
Baxi Bypass Cartridge 720874001
Baxi 720874001 bypass cartridge for Baxi ErP combi boilers, regulating flow through the bypass circuit in the hydraulic assembly.
At a glance
- Part type: Diverter valve and hydraulic components
- This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
Showing prices
£21.00
£17.50 ex. VAT · VAT at 20%
In stock
Cut-off passed — dispatches next working day
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Same-day dispatch
Ordered by 4pm Mon–Fri, 10:30am Sat.
30-day returns
Unused, in original packaging.
What it is
The Baxi 720874001 is a bypass cartridge manufactured by Baxi for use in its combi boiler range. It forms part of the diverter valve and hydraulic component group, sitting inside the hydraulic assembly where it regulates flow through the bypass circuit. By allowing a controlled path for water around the heating circuit, it helps the boiler hold a steady flow rate and temperature across the heat exchanger as demand at the taps and radiators changes.
Signs this part needs replacing
- Domestic hot water temperature swings between hot and cold during a draw-off
- The boiler cycles repeatedly or struggles to hold a steady heating temperature
- Radiators warm up when hot water is being drawn, suggesting the bypass and diverter functions are not separating correctly
- Whistling, humming or rattling from the hydraulic block area during operation
- Reduced flow through the heating circuit with the pump running normally
Before you order
- Check the GC number and the serial number suffix on the appliance data badge against the compatibility list before ordering
- Confirm the appliance model matches one of the Baxi ErP Combi variants listed for this cartridge
- This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
Mechanical
| Part type | By-Pass |
|---|---|
| Length | 0.1mm |
| Width | 0.1mm |
| Depth | 0.1mm |
Compliance
| Manufacturer part number (MPN) | 720874001 |
|---|---|
| GC number | H90-470 |
| Barcode / EAN | 720874001 |
| Commodity code | 8403 90 00 00 |
| GPC classification | Household Boilers/Furnaces/Tank Water Heaters Replacement Parts/Accessories |
| Make | Model / assembly | Reference | Years | Fitment |
|---|---|---|---|---|
| BAXI 124 ErP COMBI - SERIAL NUMBER ENDING AC | 47-077-25 | 47-077-25 | — | — |
| BAXI 124 ErP COMBI - SERIAL NUMBER ENDING BC | 47-077-25 | 47-077-25 | — | — |
| BAXI 128 ErP COMBI - SERIAL NUMBER ENDING AC | 47-077-26 | 47-077-26 | — | — |
| BAXI 128 ErP COMBI - SERIAL NUMBER ENDING BC | 47-077-26 | 47-077-26 | — | — |
| BAXI 224 ErP COMBI | 47-077-21 | 47-077-21 | — | — |
| BAXI 228 ErP COMBI | 47-077-22 | 47-077-22 | — | — |
| BAXI 424 ErP COMBI | 47-077-23 | 47-077-23 | — | — |
| BAXI 428 ErP COMBI | 47-077-24 | 47-077-24 | — | — |
| BAXI DUO-TEC 2 COMBI 28 COMPACT | 47-075-72 | 47-075-72 | — | — |
| BAXI ECOBLUE COMBI 24 | 47-075-81 | 47-075-81 | — | — |
Showing 10 of 52 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
BAXI appliance manual — 124 ErP COMBI - SERIAL NUMBER ENDING AC (GC 47-077-25), 124 ErP COMBI - SERIAL NUMBER ENDING BC (GC 47-077-25), 128 ErP COMBI - SERIAL NUMBER ENDING AC (GC 47-077-26), 128 ErP COMBI - SERIAL NUMBER ENDING BC (GC 47-077-26)
manualmanualBAXI appliance manual — 224 ErP COMBI (GC 47-077-21), 228 ErP COMBI (GC 47-077-22), 424 ErP COMBI (GC 47-077-23), 428 ErP COMBI (GC 47-077-24)
manualmanualBAXI appliance manual — DUO-TEC 2 COMBI 28 COMPACT (GC 47-075-72)
manualmanualBAXI appliance manual — ECOBLUE COMBI 24 (GC 47-075-81), ECOBLUE COMBI 28 (GC 47-075-82), ECOBLUE COMBI 33 (GC 47-075-83)
manualmanualBAXI appliance manual — ECOBLUE COMBI ErP 24 (GC 47-077-11), ECOBLUE COMBI ErP 28 (GC 47-077-12), ECOBLUE COMBI ErP 33 (GC 47-077-13)
manualmanualBAXI appliance manual — ECOBLUE PLUS COMBI 24 (GC 47-075-84), ECOBLUE PLUS COMBI 28 (GC 47-075-85), ECOBLUE PLUS COMBI 33 (GC 47-075-86)
manualmanualBAXI appliance manual — ECOBLUE PLUS COMBI ErP 24 (GC 47-077-08), ECOBLUE PLUS COMBI ErP 28 (GC 47-077-09), ECOBLUE PLUS COMBI ErP 33 (GC 47-077-10)
manualmanualBAXI appliance manual — ECOBLUE SYSTEM 12 (GC 41-077-95), ECOBLUE SYSTEM 15 (GC 41-077-96), ECOBLUE SYSTEM 18 (GC 41-077-97), ECOBLUE SYSTEM 24 (GC 41-077-98), ECOBLUE SYSTEM 28 (GC 41-077-99), ECOBLUE SYSTEM 32 (GC 41-470-01)
manualmanualBAXI appliance manual — ECOBLUE SYSTEM ErP 12 (GC 41-470-23), ECOBLUE SYSTEM ErP 15 (GC 41-470-24), ECOBLUE SYSTEM ErP 18 (GC 41-470-25), ECOBLUE SYSTEM ErP 24 (GC 41-470-26), ECOBLUE SYSTEM ErP 28 (GC 41-470-27), ECOBLUE SYSTEM ErP 32 (GC 41-470-28)
manualmanualBAXI appliance manual — MEGAFLO 2 SYSTEM 12 COMPACT GA (GC 41-075-70), MEGAFLO 2 SYSTEM 15 COMPACT GA (GC 41-075-71), MEGAFLO 2 SYSTEM 18 COMPACT GA (GC 41-075-72), MEGAFLO 2 SYSTEM 24 COMPACT GA (GC 41-075-73), MEGAFLO 2 SYSTEM 28 COMPACT GA (GC 41-075-74), MEGAFLO 2 SYSTEM 32 COMPACT GA (GC 41-075-75)
manualmanualBAXI appliance manual — NETA-TEC COMBI 24 GA (GC 47-075-51), NETA-TEC COMBI 28 GA (GC 47-075-52), NETA-TEC COMBI 33 GA (GC 47-075-53)
manualmanualBAXI appliance manual — NETA-TEC PLUS COMBI 24 GA (GC 47-075-64), NETA-TEC PLUS COMBI 28 GA (GC 47-075-65), NETA-TEC PLUS COMBI 33 GA (GC 47-075-66)
manualmanualPOTTERTON appliance manual — APOLLO 25 (GC 47-393-38), APOLLO 30 (GC 47-393-37)
manualmanualPOTTERTON appliance manual — ULTRA SYSTEM 12 ErP (GC 41-592-71), ULTRA SYSTEM 15 ErP (GC 41-592-72), ULTRA SYSTEM 18 ErP (GC 41-592-73), ULTRA SYSTEM 24 ErP (GC 41-592-74), ULTRA SYSTEM 28 ErP (GC 41-592-75)
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