Sime
Sime Air Pressure Switch Huba 605.99748
Air pressure switch for Sime boilers, referenced Huba 605.99748, used to prove fan and flue operation before ignition.
At a glance
- Part type: air pressure switch
£27.95
£23.29 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 air pressure switch is a safety device fitted to Sime gas boilers, referenced under Huba part number 605.99748. It monitors the pressure created by the combustion fan and confirms airflow before the boiler is allowed to ignite. If the switch does not prove the fan, the boiler will not fire and will normally lock out.
Signs this part needs replacing
- Boiler locks out shortly after the fan starts, with no ignition
- Fan runs but the boiler repeatedly fails to prove airflow
- Intermittent lockouts that clear on reset and return
- Fault code or lockout pattern pointing to the air pressure switch or flue pressure
- Boiler fires only when the pressure sensing tube is disturbed or reseated
Before you order
- Confirm your boiler model and GC number against the fitment list above
- Check the part number on the existing switch matches Huba 605.99748
- Inspect the sensing tube and its connections for blockages, splits or loose fit before replacing the switch
- Verify the fan is running correctly, as a failed fan can produce the same symptoms
No specification data held for this part.
| Make | Model / assembly | Reference | Years | Fitment |
|---|---|---|---|---|
| SIME ECOMFORT 30HE | 47-719-25 | 47-719-25 | — | — |
| SIME ECOMFORT PLUS 30 HE - 8104011 | 47-283-14 | 47-283-14 | — | — |
| SIME ECOMFORT PLUS 30 HE-EV (WITHOUT TIME CLOCK) - 8104025 | 47-283-33 | 47-283-33 | — | — |
| SIME ECOMFORT PLUS 30 HE-EV - 8104021 | 47-283-31 | 47-283-31 | — | — |
| SIME FORMAT DGT 25 BF GPL - 8109201 | — | — | — | |
| SIME FORMAT DGT 25 BF MET - 8109200 | — | — | — | |
| SIME FORMAT DGT 25/15 BF MET - 8109240 | — | — | — | |
| SIME FORMAT ZIP 25 BF TS MET - 8104650 | — | — | — | |
| SIME FORMAT ZIP 25 SOLAR MET - 8104676 | — | — | — | |
| SIME FORMAT ZIP 25BF TS GPL - 8104651 | — | — | — |
Showing 10 of 35 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.
SIME appliance manual — ECOMFORT 30HE (GC 47-719-25)
manualmanualSIME appliance manual — ECOMFORT PLUS 30 HE - 8104011 (GC 47-283-14)
manualmanualSIME appliance manual — ECOMFORT PLUS 30 HE-EV (WITHOUT TIME CLOCK) - 8104025 (GC 47-283-33), ECOMFORT PLUS 30 HE-EV - 8104021 (GC 47-283-31)
manualmanualSIME appliance manual — METROPOLIS DGT 25 BF GPL - 8107901, METROPOLIS DGT 25 BF LPG - 8107910, METROPOLIS DGT 25 BF MET - 8107900, METROPOLIS DGT 25 BF NG - 8107911
manualmanualSIME appliance manual — SUPERIOR 50 MKII - 8098101 (GC 41-719-11), SUPERIOR 60 MKII - 8098102 (GC 41-719-12), SUPERIOR 75 MKII - 8098103 (GC 41-719-13), SUPERIOR 90 MKII - 8098104 (GC 41-719-14)
manualmanualSIME appliance manual — SUPERIOR 60CI - 8098112 (GC 47-719-12), SUPERIOR 80CI - 8098113 (GC 47-719-13)
manualNo technical questions yet for this part.
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