Potterton
Potterton By-Pass Group Heat Box 5138658
By-pass group heat box, part 5138658, for Potterton Commercial Sirius SAT series boilers.
£121.20
£101.00 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 by-pass group heat box is a Potterton Commercial component used on Sirius SAT series commercial boilers. It forms part of the boiler's by-pass circuit, controlling flow through the heat box section of the appliance. It is supplied under part number 5138658.
Signs this part needs replacing
- The boiler cycles or overheats because the by-pass circuit is not maintaining correct flow through the heat box.
- Poor or unstable temperature control across the system that cannot be traced to other controls or components.
- Kettling or abnormal noise from the heat box area during operation.
- Visible corrosion, scale build-up, leaking or damaged seals around the by-pass group assembly.
- The by-pass group fails to operate or is seized, affecting circulation through the heat box.
Before you order
- Confirm the appliance model matches one of the Sirius SAT variants listed in the Fits section.
- Check the existing part number on the boiler against 5138658 to confirm the correct assembly is being ordered.
- Inspect the surrounding pipework and seals before fitting, as the by-pass group is part of the boiler's water circuit.
- Work on commercial gas boilers must be carried out by a suitably qualified and registered engineer.
No specification data held for this part.
| Make | Model / assembly | Reference | Years | Fitment |
|---|---|---|---|---|
| POTTERTON COMMERCIAL POTTERTON COMMERCIAL SPARES | — | — | — | |
| POTTERTON COMMERCIAL SIRIUS SAT R/1 | — | — | — | |
| POTTERTON COMMERCIAL SIRIUS SAT R2Z | — | — | — | |
| POTTERTON COMMERCIAL SIRIUS SAT RA | — | — | — | |
| POTTERTON COMMERCIAL SIRIUS SAT RA2Z | — | — | — | |
| POTTERTON COMMERCIAL SIRIUS SAT RP/1 | — | — | — | |
| POTTERTON COMMERCIAL SIRIUS SAT RS | — | — | — | |
| POTTERTON COMMERCIAL SIRIUS SAT RS2Z | — | — | — | |
| POTTERTON COMMERCIAL SIRIUS SAT RSP | — | — | — |
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.
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