Baxi
Baxi Safety Valve 3 Bar 720777801
3 bar pressure relief safety valve, Baxi part 720777801, for Neta-Tec, EcoBlue and Megaflo appliances.
At a glance
- Also known as N3887
Showing prices
£36.00
£30.00 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 Baxi 720777801 is a 3 bar safety valve used across the Baxi Neta-Tec, EcoBlue and Megaflo appliance families. It opens to relieve excess pressure from the heating or hot water circuit once the system reaches its set limit. The valve is listed against 46 Baxi models, with some fits identified by serial number suffix.
Signs this part needs replacing
- Water dripping or discharging continuously from the pressure relief discharge pipe
- System pressure creeping above its normal range, or needing repeated topping up
- The valve passing water when the system is cold
- Scale or debris visible around the valve seat or outlet
- Discharge pipe running wet or warm without the system being over pressure
Before you order
- Confirm the appliance model, and the serial number suffix where the fit list specifies one
- Check that the existing valve is rated at 3 bar
- Cross-check the part number 720777801 against the valve being removed or the appliance documentation
- Confirm the valve suits the appliance type, whether combi, system or Megaflo
Compliance
| GC number | H90-461 |
|---|---|
| Alternative numbers | N3887 |
| 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 DUO-TEC 2 COMBI 28 COMPACT | 47-075-72 | 47-075-72 | — | — |
| BAXI ECOBLUE COMBI 24 | 47-075-81 | 47-075-81 | — | — |
| BAXI ECOBLUE COMBI 28 | 47-075-82 | 47-075-82 | — | — |
| BAXI ECOBLUE COMBI 33 | 47-075-83 | 47-075-83 | — | — |
| BAXI ECOBLUE COMBI ErP 24 | 47-077-11 | 47-077-11 | — | — |
| BAXI ECOBLUE COMBI ErP 28 | 47-077-12 | 47-077-12 | — | — |
Showing 10 of 46 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 — 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 — 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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