Myson
Myson Thermocouple 900mm Q309A2788
At a glance
- Part type: Thermocouple
- Also known as 1126174
- This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
Showing prices
£20.65
£17.21 ex. VAT · VAT at 20%
In stock
Cut-off passed — dispatches next working day
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 Myson Q309A2788 is a thermocouple for gas-fired boilers and water heaters. It sits in the pilot flame and generates a small millivolt signal that holds the gas valve open while the pilot is lit; if the flame goes out, the signal stops and the valve closes. The part is used across the Myson range, including the Marathon 1000B, 1000C, 400B and 400C, and is also listed against a large number of Potterton appliances.
Signs this part needs replacing
- The pilot lights, but goes out as soon as the control knob is released.
- The boiler locks out repeatedly shortly after the pilot has been established.
- The pilot flame extinguishes during normal running, with no other fault found.
- The appliance shuts down intermittently and the pilot has to be relit each time.
- The pilot will only stay alight while the knob is physically held in.
Before you order
- Check the appliance model and GC number against the compatibility list before ordering, as this thermocouple is listed against a wide spread of boilers.
- Confirm the number marked on the existing thermocouple; older stock may carry 402103, 402117, 402174, 402257, 40225701, 906580 or Q309A2747.
- This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
Mechanical
| Part type | Thermocouples |
|---|
Compliance
| Manufacturer part number (MPN) | Q309A2788 |
|---|---|
| GC number | 390-039 |
| Barcode / EAN | 5039177533948 |
| Commodity code | 9025 19 00 00 |
| GPC classification | Household Boilers/Furnaces/Tank Water Heaters |
| Alternative numbers | 402103, 402117, 402174, 402257, 40225701, 906580, Q309A2747, 1126174 |
| Make | Model / assembly | Reference | Years | Fitment |
|---|---|---|---|---|
| MYSON MARATHON 1000B | 41-494-13 | 41-494-13 | — | — |
| MYSON MARATHON 1000C | 41-494-19 | 41-494-19 | — | — |
| MYSON MARATHON 400B | 41-494-08 | 41-494-08 | — | — |
| MYSON MARATHON 400C | 41-494-14 | 41-494-14 | — | — |
| MYSON MARATHON 500B | 41-494-09 | 41-494-09 | — | — |
| MYSON MARATHON 500C | 41-494-15 | 41-494-15 | — | — |
| MYSON MARATHON 600B | 41-494-10 | 41-494-10 | — | — |
| MYSON MARATHON 700B | 41-494-11 | 41-494-11 | — | — |
| MYSON MARATHON 800B | 41-494-12 | 41-494-12 | — | — |
| MYSON MARATHON 800C | 41-494-18 | 41-494-18 | — | — |
Showing 10 of 79 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
MYSON appliance manual — MARATHON 1000B (GC 41-494-13), MARATHON 800B (GC 41-494-12)
manualmanualMYSON appliance manual — MARATHON 1000C (GC 41-494-19), MARATHON 800C (GC 41-494-18)
manualmanualMYSON appliance manual — MARATHON 400B (GC 41-494-08), MARATHON 500B (GC 41-494-09)
manualmanualMYSON appliance manual — MARATHON 400C (GC 41-494-14), MARATHON 500C (GC 41-494-15)
manualmanualMYSON appliance manual — MARATHON 600B (GC 41-494-10), MARATHON 700B (GC 41-494-11)
manualmanualMYSON appliance manual — MIDAS B (GC 47-838-01)
manualmanualMYSON appliance manual — MIDAS BF (GC 47-494-03)
manualmanualPOTTERTON appliance manual — FLAMINGO 2 CF 20/30 (GC 41-605-16)
manualmanualPOTTERTON appliance manual — FLAMINGO CF 20/30 (GC 41-601-33)
manualmanualPOTTERTON appliance manual — FLAMINGO RS 20/30 (GC 41-601-23)
manualmanualPOTTERTON appliance manual — KINGFISHER 2 CF 100 (GC 41-607-11), KINGFISHER 2 CF 80 (GC 41-607-10)
manualmanualPOTTERTON appliance manual — KINGFISHER 2 RS 100 (GC 41-607-21), KINGFISHER 2 RS 60 (GC 41-607-19), KINGFISHER 2 RS 80 (GC 41-607-20)
manualmanualPOTTERTON appliance manual — KINGFISHER 2 RS 40 (GC 41-607-17)
manualmanualPOTTERTON appliance manual — KINGFISHER CF 100 (GC 41-601-42), KINGFISHER CF 80 (GC 41-601-39)
manualmanualPOTTERTON appliance manual — KINGFISHER CF 150 (GC 41-601-16), KINGFISHER CF 180 (GC 41-601-19), KINGFISHER CF 220 (GC 41-601-20)
manualmanualPOTTERTON appliance manual — KINGFISHER CF 40 (GC 41-601-57), KINGFISHER CF 50 (GC 41-601-58), KINGFISHER CF 60 (GC 41-601-56)
manualNo technical questions yet for this part.
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