Saunier Duval Hydraulic Block Pump Isofast F 30 E H MOD Ref. 0020037988
In the Saunier Duval Isofast range boilers, the Hydraulic Block Pump Isofast F 30 E H MOD Ref. 0020037988 is a component that conducts and distributes water between the boiler circuits. When this part fails, you may notice leaks, pressure loss, or issues with domestic hot water production. It is compatible with models such as Isofast F 30 E H-MOD, Isofast F 35 E, and Themafast F 30 E H-MOD, among others. It is recommended to replace the hydraulic block when fault codes F.75, F.23, F.24, or F.20 appear.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference 0020037988
Hydraulic group with reference 0020037988. 12 verified compatibilities: Isofast Condens F 35 E and Isofast Condens F 30 E.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval Isofast Condens F 35 E | Isofast Condens | Contrasted |
| Saunier Duval Isofast Condens F 30 E | Isofast Condens | Contrasted |
| Saunier Duval Isofast 21 Condens F 35-B | Isofast Condens | Contrasted |
| Saunier Duval Isofast 21 Condens F 25 | Isofast Condens | Contrasted |
| Saunier Duval Isofast F 30 E H-MOD | Isofast (non-condensing) | Contrasted |
| Saunier Duval Isofast F 35 EA | Isofast (non-condensing) | Contrasted |
| Saunier Duval Isofast F35E H-MOD | Isofast (non-condensing) | Contrasted |
| Saunier Duval Themafast Condens F 24E | Themafast Condens | Contrasted |
| Saunier Duval Themafast Condens F 30E | Themafast Condens | Contrasted |
| Saunier Duval Themafast Condens F 30 H-MOD | Themafast Condens | Contrasted |
| Saunier Duval Themafast F 30 E H-MOD | Themafast | Contrasted |
| Saunier Duval Themafast F 25 E H-MOD | Themafast | Contrasted |
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. 0020037988 is the part for your boiler
What determines it is not the boiler model, but the reference printed on the part you already have installed.
- Find the reference printed on the installed part and check whether it matches the catalogue reference 0020037988. If it is not visible, do not identify the part from its shape alone.
- Check the full boiler model on its data plate and look for it in the model associations on this page.
- Compare the connections and physical body with the original part before installation.
- If anything is unclear, send us a photo of the marking via WhatsApp before placing your order.
Symptoms and faults that the hydraulic group 0020037988 resolves.
The hydraulic group includes the valve, the by-pass, and the water connections. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
The temperature of the hot water fluctuates while using the faucet.
Cause: The hydraulic block controls the flow and the mixture towards the domestic hot water circuit, and an internal fault causes those variations.
Make sure that the mains pressure is stable and that no other tap is open at the same time before changing the block.
- 02
A knocking sound is heard when switching between heating and domestic hot water.
Cause: The diverter valve integrated into the block does not complete its travel properly and hits the stop when switching.
Confirm that the noise always occurs when switching modes, and not continuously, before replacing the part.
- 03
The boiler heats the heating well, but the domestic hot water does not reach the temperature set on the control.
Cause: The block does not completely close the passage to the heating circuit and reduces the available power for domestic hot water.
Check the domestic hot water temperature set on the control and rule out a dirty inlet filter before replacing the block.
- 04
Moisture or dripping appears under the boiler, near where this block is mounted.
Cause: The internal seals of the block degrade with temperature cycles and gradually allow water to pass through.
Dry the area, start the boiler, and locate the exact source of the drip before declaring the block as faulty.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F.75 | The control does not detect an increase in pressure when the pump starts (lack of water/pressure or pump/sensor fault). | If the circulator (block 0020037988) is blocked, does not start, or does not respond, the pressure sensor does not detect the expected increase and the boiler locks out with F.75; check electrical/PWM start-up, consumption, and that the rotor spins after bleeding. |
| F.23 | Safety shutdown due to excessive temperature difference between flow and return. | A blocked pump or one working at minimum power prevents circulation, increases the ΔT, and triggers F.23; check that the circulator is rotating, its consumption and flow rate, and bleed the primary. |
| F.24 | Safety shutdown due to excessively rapid temperature rise. | If the circulator of block 0020037988 is seized or has insufficient power, the water does not dissipate heat and the temperature rises quickly; check the pump's rotation/consumption, PWM signal, and bleed the circuit. |
| F.20 | Safety shutdown of the temperature limiter (overheating). | The lack of circulation due to a blocked pump in block 0020037988 causes overheating in the heat exchanger; check the start and flow of the circulator, free the shaft if it is seized, and bleed. |
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.
Data sheet for the Saunier Duval hydraulic group 0020037988
- Catalogue reference
- 0020037988
- Brand
- Saunier Duval
- Type of part
- Hydraulic units
- Units in stock
- 7 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- Delivery time shown at checkout
- Return
- 14 days
Frequently asked questions about the hydraulic group 0020037988
Is this hydraulic block compatible with the Isofast Condens F 30 E boiler?
Can I use this block in a Themafast Condens F 24E boiler?
Is this block suitable for the Isofast F 35 EA boiler?
What fault codes are common in this hydraulic block?
How many models are compatible with this hydraulic block?
What is the reference for this hydraulic block?
Spare parts related to Saunier Duval Isofast Condens
