Powermax
Powermax Thermostat 82 Degree P784
Powermax P784 82°C thermostat for Powermax gas boilers, replacing earlier numbers P520 and P638 across 24 appliance models.
At a glance
- Part type: Thermostat
£64.80
£54.00 ex. VAT · VAT at 20%
Same-day dispatch
Ordered by 4pm Mon–Fri, 10:30am Sat.
30-day returns
Unused, in original packaging.
What it is
The Powermax P784 is an 82°C thermostat used in Powermax gas boilers. It sits in the appliance's temperature control circuit and switches the burner in response to the heat it senses, holding the boiler at its designed operating temperature. The part is listed against 24 Powermax models and is the current number for the earlier P520 and P638 thermostats.
Signs this part needs replacing
- The boiler runs hotter than the set temperature or overheats
- The burner keeps firing after the appliance has reached temperature
- The overheat thermostat trips and the boiler locks out
- Radiator or hot water temperatures fluctuate instead of holding steady
- The appliance shows no response to changes at the temperature control
Before you order
- Check the GC number on the appliance data badge against the compatibility list below
- Confirm the thermostat fitted is marked P784, or carries one of the earlier numbers P520 or P638
- Note the boiler model and serial number before ordering so the correct variant is supplied
Mechanical
| Part type | Thermostat |
|---|
Performance
| Temperature rating | 82 °C |
|---|
Compliance
| Manufacturer part number (MPN) | P784 |
|---|---|
| GC number | 397-755 |
| Commodity code | 9032 10 00 00 |
| GPC classification | Household Boilers/Furnaces/Tank Water Heaters Replacement Parts/Accessories |
| Alternative numbers | P520, P638 |
| Make | Model / assembly | Reference | Years | Fitment |
|---|---|---|---|---|
| BAXI Powermax 140 | — | — | — | |
| BAXI Powermax 155X | — | — | — | |
| POWERMAX 135 | 41-389-01 | 41-389-01 | — | — |
| POWERMAX 140 FOV | 41-389-09 | 41-389-09 | — | — |
| POWERMAX 140 FSS | 41-389-10 | 41-389-10 | — | — |
| POWERMAX 155 CP FOV C/W PUMP & CLOCK | 41-389-08 | 41-389-08 | — | — |
| POWERMAX 155 CP SS | 41-389-05 | 41-389-05 | — | — |
| POWERMAX 155 FOV STD MODEL | 41-389-06 | 41-389-06 | — | — |
| POWERMAX 155 P FOV C/W PUMP | 41-389-07 | 41-389-07 | — | — |
| POWERMAX 155 P SS | 41-389-04 | 41-389-04 | — | — |
Showing 10 of 24 compatible appliances.
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.
POWERMAX appliance manual — 135 (GC 41-389-01)
manualmanualPOWERMAX appliance manual — 140 FOV (GC 41-389-09), 140 FSS (GC 41-389-10)
manualmanualPOWERMAX appliance manual — 155 CP FOV C/W PUMP & CLOCK (GC 41-389-08), 155 CP SS (GC 41-389-05), 155 FOV STD MODEL (GC 41-389-06), 155 P FOV C/W PUMP (GC 41-389-07), 155 P SS (GC 41-389-04), 155 SS (GC 41-389-03), 155X FOV (GC 41-389-14), 155X FSS (GC 41-389-13)
manualNo technical questions yet for this part.
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