TRV22830ADAP
M28 → M30
Genuine Myson
No Drain-Down Required
Hexagonal Head
Myson TRV22830ADAP — Genuine M28 to M30 TRV head adaptor | Allows modern 30mm TRV heads to fit pre-1997 Myson M28 valve bodies | Hexagonal anti-spin design | Fits Drayton Wiser and standard replacement heads
The Myson TRV22830ADAP is the genuine OEM adaptor for upgrading pre-1997 Myson TRV valve bodies to accept current M30×1.5mm thermostatic heads, including smart TRVs such as the Drayton Wiser Radiator Thermostat. Myson revised their TRV thread standard from M28 to M30 in 1997, making this adaptor essential when replacing old heads on existing Myson valve bodies — with no need to drain down or disturb the pipework.
The adaptor screws directly onto the existing M28 valve body. The new TRV head then screws onto the M30 male thread on top. The hexagonal profile on the upper section prevents the adaptor from spinning when the TRV head is tightened or adjusted — a key advantage over round-bodied alternatives, which can rotate and cause difficulty at installation.
This is also known by the legacy part number 2TRVADAP and fits Myson, Westherm, Comap and similar M28 valve bodies of the same period. It is a solid, precision-machined component, not a lightweight substitute.
💡 Compatible with Smart TRVs
This adaptor allows the Drayton Wiser Smart Radiator Thermostat (WV704R0A0902) and other M30×1.5mm heads to fit onto older Myson M28 valve bodies — making it ideal for smart heating system upgrades without full valve replacement.
Key Features
M28 Female → M30 MaleFemale M28×1.5mm thread accepts the existing Myson valve body; male M30×1.5mm thread accepts modern TRV heads — genuine Myson specification.
Hexagonal Anti-Spin HeadThe hex-profile upper section prevents the adaptor from rotating when heads are tightened or manually adjusted — avoids the common problem with round-top alternatives.
No Drain-Down RequiredFits directly onto the existing valve body without draining the central heating system — simply remove the old head and screw on the adaptor.
Genuine Myson OEM PartAuthentic Myson part (TRV22830ADAP / 2TRVADAP) — correct thread pitch and dimensions for proper engagement and long-term reliability.
Wide CompatibilitySuitable for Myson, Westherm, Comap and other M28 valve bodies from the pre-1997 era. Also compatible with smart TRVs using the M30×1.5mm standard.
Solid ConstructionPrecision-machined metal construction — robust and durable for long-term radiator valve use in central heating systems.
Technical Specifications
| Specification |
Detail |
| Part Number |
TRV22830ADAP (also 2TRVADAP) |
| Brand |
Myson |
| Function |
TRV head adaptor — M28 valve body to M30 head |
| Bottom Thread (Valve Body) |
M28 × 1.5mm (female) — fits pre-1997 Myson TRV 2-Way valve bodies |
| Top Thread (TRV Head) |
M30 × 1.5mm (male) — accepts all standard M30 thermostatic heads |
| Upper Profile |
Hexagonal — prevents rotation during installation and adjustment |
| Material |
Metal (precision machined) |
| Installation |
No drain-down required — direct replacement of existing TRV head |
| Compatible TRV Heads |
All M30 × 1.5mm heads including Drayton Wiser, standard manual TRVs |
| Compatible Valve Bodies |
Myson TRV 2-Way (pre-1997), Westherm, Comap (M28 bodies) |
What's Included
In the Box
1 × Myson TRV22830ADAP M28–M30 adaptor. Note: TRV head and valve body are NOT included.
⚠️ Adaptor Only — This listing is for the adaptor only. A TRV valve body and TRV head are not included. Ensure your existing valve body has an M28 × 1.5mm female thread before ordering. If you are unsure, email a photograph of your existing valve for identification.
Installation Notes
Remove the existing TRV head by unscrewing anti-clockwise. The adaptor screws clockwise onto the existing M28 valve body and can be tightened with a spanner on the hex flats. No need to drain the heating system — the valve body remains in place. Once the adaptor is fitted, the new M30 TRV head screws directly onto the M30 male thread. Check for leaks after installation and refill as necessary.
For systems being upgraded to smart TRVs such as the Drayton Wiser, this adaptor avoids the cost of full valve replacement and system drain-down — saving significant time per radiator on a whole-house smart heating upgrade.
Frequently Asked Questions
Do I need to drain the central heating system to fit this adaptor?No. The adaptor fits directly onto the existing valve body with the valve closed. Simply remove the old TRV head and screw the adaptor on in its place — no drain-down required.
Will this fit the Drayton Wiser Smart Radiator Thermostat?Yes. The Drayton Wiser Smart Radiator Thermostat (WV704R0A0902) uses a standard M30 × 1.5mm thread and will fit directly onto this adaptor after it is installed on the M28 valve body.
Why does my Myson TRV head not fit my valve body?Myson changed their TRV head thread from M28 to M30 in 1997. If you have a valve body installed before 1997, the newer M30 heads will not fit without this adaptor.
What is the difference between the hex-top and round-top adaptors?The hexagonal upper profile on the Myson TRV22830ADAP prevents the adaptor from spinning when the TRV head is tightened or turned. Round-top alternatives (often cheaper) can rotate and make installation and adjustment difficult.
Does this fit Westherm or Comap valves?Yes, provided the valve body has an M28 × 1.5mm female thread — the same thread used on Myson pre-1997 bodies. This includes many Westherm and Comap bodies of the same period. If in doubt, check the thread specification on your existing valve body.
Is this a genuine Myson part?Yes. The TRV22830ADAP (also known as 2TRVADAP) is the genuine Myson OEM adaptor with the correct thread pitch and dimensions for a secure, leak-free fit.
