Vaillant Safety Valve VMW 236/3-5 Ref. 178985
Safety valve for Vaillant boilers from the VM and VMW series. The body is made of brass, with a 1/2" threaded connection and flow direction arrow. It features a bleed lever instead of a threaded plug. The replacement requires first confirming the fault of the part through technical diagnosis, even when it drips continuously, does not restore pressure after bleeding, or loses tightness.
- Type of part
- Safety valves
- Status
- Refurbished
- Catalogue reference
- 178985
- Warranty
- 1 year
Vaillant boilers compatible with reference 178985
Safety valve with reference 178985. Eight confirmed compatibilities: VMW 236/3-5 and VMW 242/4-5.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Vaillant VMW 236/3-5 | Atmoblock / Ecoblock (VMW compact wall-mounted mixed series) | Contrasted |
| Vaillant VMW 242/4-5 | Atmoblock / Ecoblock (VMW compact wall-mounted mixed series) | Contrasted |
| Vaillant VMW 306/5-5 | Atmoblock / Ecoblock (VMW compact wall-mounted mixed series) | Contrasted |
| Vaillant VMW 346/5-5 | Atmoblock / Ecoblock (VMW compact wall-mounted mixed series) | Contrasted |
| Vaillant VM 240/3-5 | VM series (wall-mounted heating only) | Contrasted |
| Vaillant VM 242/4-5 | VM series (wall-mounted heating only) | Contrasted |
| Vaillant VM 246/3-5 | VM series (wall-mounted heating only) | Contrasted |
| Vaillant VM 306/5-5 | VM series (wall-mounted heating only) | 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. 178985 is the part for your boiler
The part reference, model, and equipment revision must be verified against the manufacturer's documentation.
- Find the reference printed on the installed part and check whether it matches the catalogue reference 178985. 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 that require diagnosis in the safety valve 178985
The safety valve releases pressure when the circuit exceeds its setting. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
It continuously leaks from the bleed lever.
Cause: If the lever mechanism does not seat properly after a shot, there is a constant water leak.
Pull the lever a couple of times with the boiler cold to see if it settles again and the dripping stops.
- 02
After operating the lever to bleed, it does not close properly and continues to drip.
Cause: Lime residues or dirt on the seat, dragged when lifting the lever, can get trapped and prevent closure.
Clean around the lever and operate it several times in a row before declaring the valve faulty.
- 03
The circuit is losing pressure and water needs to be replenished more frequently than usual.
Cause: Each opening of the pressure relief valve releases water from the circuit, although the dripping may not always be noticeable at first glance.
Check if the pressure drop coincides with the times when the boiler heats more intensely.
- 04
The valve is leaking from the brass body, not from the lever.
Cause: It could be a leak from the 1/2" connection or from the body itself, different from a fault in the adjustment mechanism.
Check with soapy water if the leak is coming from the thread or from the body before replacing the gas valve due to a calibration fault.
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 safety valve Vaillant 178985
- Catalogue reference
- 178985
- Uniclima internal SKU
- VSEVMW236
- Brand
- Vaillant
- Type of part
- Safety valves
- Units in stock
- 3 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.
- Connection
- 1/2" (engraved on the brass body)
- Bleed
- Bleed lever (does not have a threaded plug)
Manuals and technical documentation
Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.
- Vaillant VMW 236/3-5 Manual (PDF) Document © Vaillant, provided as a technical reference.
Frequently asked questions about the safety valve 178985
Is this safety valve suitable for the Vaillant VMW 236/3-5?
Does the valve Ref. 178985 have a threaded bleed cap or a lever?
What connection does the safety valve have for the Vaillant VM 306/5-5?
When should the safety valve of the Vaillant VMW 236/3-5 be replaced?
How many models are compatible with the safety valve VSEVMW236?
Spare parts related to Vaillant Atmoblock / Ecoblock (VMW compact wall-mounted combi series)
