Air Pressure Switch Isofast F 30 E - Code 605.99534

Saunier Duval boilers compatible with reference S5744100

Pressure switch with reference S5744100. 21 verified compatibilities: F 30 E H-MOD and F 35 E1.

Proven compatibility

Can't see your model or have questions? The printed reference takes precedence. How to check it · Send us a photo via WhatsApp.

How to check if ref. S5744100 is the part for your boiler

The part reference, model, and equipment revision must be verified against the manufacturer's documentation.

1. Find the reference printed on the installed part and check whether it matches the catalogue reference S5744100. If it is not visible, do not identify the part from its shape alone.
2. Check the full boiler model on its data plate and look for it in the model associations on this page.
3. Compare the connections and physical body with the original part before installation.
4. If anything is unclear, send us a photo of the marking via WhatsApp before placing your order.

Symptoms that require diagnosis in the pressure switch S5744100

The pressure switch controls the air or water pressure to authorize operation. These are the typical symptoms and what to do:

Common symptoms and faults

• 01

  The boiler starts the fan, stops for a few seconds, and tries again several times before locking.

  Cause: The control unit tries to ignite the boiler when it does not receive the signal from the pressure switch at first, until it locks out for safety.

  Count how many times it retries before locking; if it is always the same number of attempts and the same point, it could be a constant pressure issue.

• 02

  The fault appears just when the weather changes, for example with fog or high humidity.

  Cause: Moisture can condense inside the pressure intake tube and give a false reading of the pressure switch.

  Check for water or condensation inside the silicone tubes that connect the pressure switch before replacing it.

• 03

  The electrode or flame sensor has been replaced and the fault remains exactly the same.

  Cause: If the lockout occurs during the pre-purge phase, before the spark, the problem is not in the flame section but in the flue gas validation performed by the pressure switch.

  Check at what exact moment in the cycle the boiler locks: if it is before the spark, focus on the air circuit and the pressure switch, not on the electrode.

• 04

  Before blocking, the extractor can be heard running normally, without any strange noises.

  Cause: If the extractor sounds fine but the pressure switch still does not switch, the fault points more to the pressure switch itself or its air intake circuit than to the fan.

  First, rule out the fan by the sound, and if it sounds normal, check the cleanliness and securing of the pressure intake pipes before purchasing the pressure switch.

Fault codes Saunier Duval that require diagnosis

These symptoms can have more than one cause. If your boiler displays a fault code, send it to us via WhatsApp along with a photo of the labeling, and we'll tell you if this is the part.

Datasheet for Saunier Duval pressure switch S5744100

Catalogue reference

S5744100

Uniclima internal SKU

PSDIF30EA

Brand

Saunier Duval

Type of part

Pressure switches

Units in stock

7 units

Status

Refurbished

Warranty

1 year

Shipping

Delivery time shown at checkout

Return

14 days

Part data and available documentation

Contrast the label codes, PCB, and revision with the installed part; they are not necessarily equivalent references.

Component code

605.99534

Set (opening/closing)

59/51 Pa

Contact electric charge

1(0.5)A / 250V~

Internal code

116189

Manufacturing date (week/year)

07/04

Batch code

K02RHE (alternative reading: KOZAHE, ambiguous characters)