The Big Overview: Adapters for Thermostatic Valves

You have probably just bought a new thermostat and are trying to attach it to your radiator valve. But somehow it doesn’t work. The solution seems simple: You need an adapter for your radiator valve.

However, as there is a veritable jungle of valves, it is not so easy to find the right adapter for the right radiator valve.

Don’t worry, you are not the only one facing this problem.

In this article, I would therefore like to give you an overview of the various adapters for different thermostatic valves. In this article you will find the following:

1. A guide to replacing your thermostat with an adapter.
2. An overview of all valves for which adapters are available.
3. An overview of all valves for which there are no adapters.
4. An overview of all valves for which no adapters are required.

Help: My thermostat needs an adapter

When I moved into my new flat in 2014, my electronic thermostats did not fit the existing radiator valves. I then did some research and found that information on suitable adapters for the large number of existing radiator valves was very scarce.

Over the years, this article with the big overview of adapters for thermostatic valves has therefore been created, which is updated and brought up to date at regular intervals. In this context, I would also like to thank the companies Kieback&Peter and eQ-3 AG/Staudigl, who have given me permission to use their radiator valve images in this article. Another thanks goes to the many readers who enrich this database with their pictures and comments.

Instructions: Fitting the adapter and thermostat

Before we start looking for the right adapter, you can see in the following illustrations how old thermostats are exchanged for new thermostats and adapters are used. It’s actually very easy, so don’t worry.

Tip: A Water pump pliers* is a suitable tool for dismounting the thermostats.

First we start with installation instructions for a Vaillant radiator valve with dimensions 30/30.5 mm, a corresponding metal adapter and the Classic L electronic radiator thermostat.

• Step 1: Carefully dismantle the old thermostat. Unscrew the thermostat to make it easier and loosen the screw ring counterclockwise. You can use a Water pump pliers* if the thermostat is too tight.
• Step 2: attach the adapter to the radiator valve using an Allen key (usually supplied).
• Step 3: After fixing the adapter, you can mount your thermostat on it. Then carefully tighten the mounting ring of the thermostat with the water pump pliers. That’s it.

In the second tutorial, reader Holger Schilling (see Holger’s comment (german Version)) has documented his thermostat replacement and shows how he successfully installed an adapter for a “Pont a Mousson” M28 x 1.5 radiator valve. Many thanks for the illustrations Holger.

Here, too, the thermostat is first dismounted and the adapter is attached to the valve. Then the new thermostat can be attached to the adapter and is ready for use.

FAQ – Questions and answers

Before we get started, here is a summary of the most important questions and answers:

Metal or plastic adapter for radiator valves?

I would choose a metal adapter as they are far more stable and have much better thermal conductivity than plastic adapters.

Why don’t the provided adapters fit on my radiator valve?

The enclosed adapter sets usually only fit the Danfoss valves RA, RAV and RAVL, as Danfoss valves are very common. If none of the adapters fit your valves, you do not have a Danfoss valve and need another adapter. This overview will help you.

How do I determine the connection / thread of a radiator valve?

The connection and the thread are usually specified in the form “M30 x 1.5” or similar. “M30” corresponds to a thread diameter (connection diameter) of 30 mm and “1.5” corresponds to the thread pitch of 1.5 mm.

Tip: A vernier caliper* is recommended for exact determination of the connections and thread dimensions.

What is the open dimension and the closed dimension of a radiator valve?

The open dimension corresponds to the distance from the thread to the end of the stuffing box pin when the valve is open. The closed dimension corresponds to the distance from the thread to the end of the stuffing box pin when the valve is closed.

There are no adapters for my valves. What can I do?

If there are no adapters for your valves, the only option is usually a valve replacement. However, this can be carried out by a specialist company without any problems.

Note: When replacing the valve, your heating system does not have to be drained! It is possible to freeze the pipes locally and thus have the valve replaced by a specialist company. The following video is an excellent demonstration of the principle of local icing:

You are currently viewing a placeholder content from YouTube. To access the actual content, click the button below. Please note that doing so will share data with third-party providers.

More Information

Unblock content Accept required service and unblock content

Overview – Adapter for thermostatic valves

In order to find out which radiator valve you are dealing with, I have tried to create a suitable overview. Many of the pictures are from the eQ-3 overview, which is really recommended: “Compatibility of electronic radiator thermostats with standard radiator valves (German Version)“. Another large part of the pictures comes from the comments of this or the german version of this article, which were uploaded by you, the many readers. Many thanks for that!

Below you will find the overview of radiator valves sorted alphabetically with pictures of most radiator valves as well as the matching adapters and partly also with associated thermostats.

Tip: I recommend using a vernier caliper* to determine the exact connections and thread dimensions and a Water pump pliers* to dismount and install the thermostats.

Adapter for Comap / SAR valves – M28 x 1.5

In addition to the radiator valve Comap / SAR M28 x 1,5, there is also a valve from Comap / SAR with the thread dimension M30 x 1,5.

Note: No adapter is required for the Comap / SAR M30 x 1.5. You will find this in the section “Radiator valves – no adapter required!“

Valve	Connection/ Thread	Offenmaß [mm]	Schließmaß [mm]	Adapter
Comap /SAR	M28 x 1,5	10,7	8,3	JA

Thermostats without adapter: The following current Herz thermostats fit onto Herz M28 x 1.5 valves:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter notes	Adapter*
Adapter manufacturer: Heimeier, Eurotronic (700100) various stable adapter for heart valves M28 x 1.5 from M28 x 1.5 to M30 x 1.5 Not for valve radiators

Offers for Herz M28 x 1,5 Adapter:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter for Ista (Oventrop) valves – M32 x 1.0

For a long time, the energy service provider Ista had its own radiator valves and thermostats in its product portfolio. These had the thread dimension M32 x 1.0 and were most likely manufactured for Ista by the company Oventrop. This can be recognised by the fact that the imprint “OV” (stands for Oventrop) can be seen on the Ista valves.

The Ista M32 x 1.0 is therefore most likely identical in construction to the Oventrop M32 x 1.0. For this reason, the Oventrop Thermostats Uni LI ISTA* also fit the Ista valves and the Ista adapters fit Oventrop M32 x 1.0 valves.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Ista / Oventrop	M32 x 1,0	15,3	11,5	YES

Thermostats without adapter: The following current Thermostats fit on the Ista M32 x 1.0 valve:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter notes	Adapter*
Adapter manufacturer: Heimeier, Eurotronic (700112) various stable adapter for Ista/ Oventrop valves M32 x 1.0 from M32 x 1.0 to M30 x 1.5 Not for valve radiators

Offers for Ista / Oventrop M32 x 1.0 Adapter:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter for Markardys (MMA) valves – M28 x 1.5

There are two valves from Markardys with the thread size M28 x 1.5, which are shown below. The corresponding adapters M28 x 1.5 to M30 x 1.5 fit on both valves.

Note: Different sources refer to Markardys at one time and Markaryd at another. I assume that they are one and the same company. Unfortunately, I don’t know which is the real company name.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Markardys (MMA)	M28 x 1,5	11,6	9,9	YES
Markardys (MMA)	M28 x 1,5	9,3	7,8	YES

Adapter notes	Adapter*
Adapter manufacturer: Heimeier, Eurotronic (700107) various stable adapter for Markardys valves M28 x 1.5 from M28 x 1.5 to M30 x 1.5 Not for valve radiators

Offers for Markardys (MMA) Valves M28 x 1.5 Adapter:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter for Meges valves – M38 x 1.5

For a long time there were no valve adapters for Meges valves, but this has now changed for the M38 x 1.5 valve (thanks Martin in the comments of haustechnikverstehen.de for the tip).

Note: There are still no adapters for the Meges M27 x 1.0. You will find this in the section “Radiator valves without matching adapters“.

Hinweis: Für das Meges M27 x 1,0 gibt es noch immer keine Adapter. Ihr findet dies im Abschnitt „Heizkörperventile ohne passende Adapter“

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Meges	M38 x 1,5	16,6	13,5	YES

Thermostats without adapters: The following thermostats fit onto Meges M38 x 1.0 valves:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Hinweise zum Adapter	Adapter*
Adapter manufacturer: Eurotronic (700113) stable adapter for Meges M38 x 1.5 from M38 x 1.5 to M30 x 1.5 Not for valve radiators

Offers for Meges M38 x 1.5 Adapter:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter for Ondal valves – M38 x 1.5

The Ondal radiator valves with matching adapter came from the Oreg company and have a thread dimension of M38 x 1.5. In addition to the Ondal M38 x 1.5, there is also the Oreg / Ondal 30mm with 12 notches. 

Note: There are still no adapters for the Oreg/Ondal 30mm with 12 notches. You will find this in the section “Radiator valves without suitable adapters”.

Hinweis: Für das Oreg/Ondal 30mm mit 12 Kerben gibt es noch immer keine Adapter. Ihr findet dies im Abschnitt „Heizkörperventile ohne passende Adapter“

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Ondal	M38 x 1,5	15,6	13,9	YES

Adapter notes	Adapter*
Adapter manufacturer: Heimeier, Eurotronic (700108) various stable adapter for Ondal M38 x 1.5 from M38 x 1.5 to M30 x 1.5 Not for valve radiators

Offers for Ondal M38 x 1.5 Adaper:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter for Orkli valves – M28 x 1.0

There is an adapter for Orkli valves M28 x 1.0 under the manufacturer’s number 700118 from Eurotronic (EAN 4260012710991) , but it is difficult to find on the internet at the moment.

Note: No adapter is required for the Orkli M30 x 1.5 according to the factory standard. You will find this in the section “Radiator valves – no adapter required!“.

Note: There are still no adapters for the Orkli M28 x 1.0 with 4 prongs and the Orkli M30 x 1.5 with 4 prongs. You can find them in the section “Radiator valves without matching adapters“.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Orkli	M28 x 1,0	17,3	14,9	YES

Adapter notes	Adapter*
Adapter manufacturer: Eurotronic (700118) stable adapter for Orkli M28 x 1.0 from M28 x 1.0 to M30 x 1.5 Not for valve radiators

Offers for Orkli M28 x 1.0 Adaper:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter for Oventrop radiator valves

Oventrop is a German company and their thermostats are present in many households. Radiator valves from Oventrop are now produced as standard with the thread dimension M30 x 1.5 according to the factory standard. Nevertheless, Oventrop makes exceptions in order to serve a larger market. For example, there are also Oventrop thermostats with matching thread dimensions for valves from Danfoss, Ista, Herz, Vaillant, Rossweiner, Meges and many more:

• Oventrop Thermostat UniXD* fits on Danfoss RA valves
• Oventrop Thermostat UniLDV* fits on Danfoss RAV valves
• Oventrop Thermostat UniLDVL* fits on Danfoss RAVL valves
• Oventrop Thermostat Uni LI ISTA* fits on ISTA M32 x 1.0
• Oventrop Thermostat Uni LV Vaillant* fits on Vaillant 30/30.5 mm
• Oventrop Thermostat Uni LA Herz fits on Herz M28 x 1.5
• Oventrop Thermostat Uni LR Rossweiner* fits on Rossweiner M33 x 2.0
• Oventrop Thermostat Uni LM Meges* fits on Menges M38 x 1.5
• usw.

Note: No adapter is required for the Oventrop M30 x 1.5 according to factory standard. You will find this in the section “Radiator valves – no adapter required!“.

Note: There are no adapters for the Oventrop M40 x 1.5. You will find this in the section “Radiator valves without matching adapters“.

Adapter for Oventrop valves – M30 x 1.0

Until the 90s, Oventrop produced radiator valves with the thread size M30 x 1.0. You will find suitable adapters for this in the following. Here, too, the following applies: By measuring the valve neck diameter, it is comparatively easy to find out which dimensions the valve has. Oventrop valves are usually marked “OV“.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Oventrop	M30 x 1,0	15,1	11,4	YES

Adapter notes	Adapter*
Adapter manufacturer: Heimeier, Eurotronic (700098) various stable adapter for Oventrop valves M30 x 1.0 from M30 x 1.0 to M30 x 1.5 Not for valve radiators

Offers for Oventrop valves M30 x 1.0 Adapter:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter for Pettinaroli (Fratelli ) valves – M28 x 1.5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Pettinaroli (Fratelli)	M28 x 1,5	20,7	18	YES

Adapter notes	Adapter*
Adapter manufacturer: Eurotronic (700117) stable adapter for Pettinaroli valves M28 x 1.5 from M28 x 1.5 to M30 x 1.5 Not for valve radiators

Offers for Pettinaroli valves M28 x 1.5 Adapter:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter for Pont a Mousson valves – M28 x 1.5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Pont a Mousson	M28 x 1,5	9,6	8,2	YES

Adapter notes	Adapter*
Adapter manufacturer: Xavax, eQ-3 stable adapter for Pont a Mousson valves M28 x 1.5 from M28 x 1.5 to M30 x 1.5 Not for valve radiators

Offers for Pont a Mousson valves M28 x 1.5 Adapter:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter for Remagg valves – M28 x 1.5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Remagg	M28 x 1,5	12	10,1	YES

Adapter notes	Adapter*
Adapter manufacturer: Xavax, eQ-3 stable adapter for Remagg valves M28 x 1.5 from M28 x 1.5 to M30 x 1.5 Not for valve radiators

Offers for Remagg valves M28 x 1.5 Adapter:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter for Rossweiner valves – M33 x 2.0

The Rossweiner company produced under its own brand until 1998, since then it has belonged to the Aalberts Industries Group and was assigned to the Meibes Group within the corporation in 2008. The original Rossweiner radiator valves had a thread size of M33 x 2.0. Today, radiator valves and thermostats are still produced under the Meibes Group, but these have a thread size of M30 x 1.5 according to the factory standard.

Note: No adapter is required for the Rossweiner M30 x 1.5 according to the factory standard. You will find this in the section “Radiator valves – no adapter required!“.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Rossweiner	M33 x 2,0	9,1	7,0	YES

Thermostats without adapters: The following thermostats fit onto Rossweiner valves M33 x 2.0 valves:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter notes	Adapter*
Adapter manufacturer: Heimeier, Eurotronic (700115) various stable adapter for Rossweiner valves M33 x 2.0 from M33 x 2.0 to M30 x 1.5 Not for valve radiators

Offers for Rossweiner valves M33 x 2.0 Adapter:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter for Sam / Slovarm valves – M28 x 1.5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Sam / Slovarm	M28 x 1,5	5,6	2,7	YES

Adapter notes	Adapter*
Adapter manufacturer: Xavax, eQ-3 stable adapter for  Sam / Slovarm  valves M28 x 1.5 from M28 x 1.5 to M30 x 1.5 Not for valve radiators

Offers for Sam / Slovarm valves M28 x 1.5 Adapter

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter für TA Ventile – M28 x 1,5

The companies TA and Heimeier were affiliated to the IMI Group in the 1990s and were subsequently known under the company name “TA Heimeier”. In 2014, “TA Heimeier” then became “IMI Hydronic Engineering”. Today, radiator valves from IMI Hydronic have the M30 x 1.5 thread dimension as standard according to the factory standard.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
TA	M28 x 1,5	10,7	8,6	YES

Adapter notes	Adapter*
Adapter manufacturer: Heimeier, Eurotronic (700102), various, universal adapter stable adapter for TA valves M28 x 1.5 from M28 x 1.5 to M30 x 1.5 Not for valve radiators

Offers for TA valves M28 x 1.5 Adapter:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter for Vaillant valves – 30/ 30.5 mm

The heating system manufacturer Vaillant also no longer has its own radiator valves or thermostatic heads in its product portfolio. The original Vaillant radiator valve had the dimensions 30 / 30.5 mm. Since I have also installed Vaillant radiator valves in my flat, I can say that the adapters for Vaillant valves work very well.

Note: There are no adapters for the Vaillant M42 x 1.5. You will find this in the section “Radiator valves without matching adapters“.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Vaillant	30,5 mm	9,8	8,8	YES

Thermostats without adapters: The following thermostats fit onto Vaillant valves (30/30.5 mm) valves:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter notes	Adapter*
Adapter manufacturer: Heimeier, Eurotronic (700097) various, universal adapters Stable adapter for Vaillant valves (30/30.5 mm) from Vaillant (30/30.5 mm) to M30 x 1.5 Not for valve radiators

Offers for Vaillant valves (30/30.5 mm) Adapter:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Adapter für VAMA Ventile – M28 x 1,0

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
VAMA	M28 x 1,0	–	–	YES

Call: Unfortunately, I do not yet have a suitable figure for the radiator valves. If you own VAMA valves M28 x 1.0, I would be pleased if you could send me photos or a comment with a picture attachment. I will then post them here.

Adapter notes	Adapter*
Adapter manufacturer: Eurotronic (700114), various stable adapter for VAMA M28 x 1.0 from VAMA M28 x 1.0 to M30 x 1.5 Not suitable for valve radiators

Offers for VAMA M28 x 1.0 Adapter:

* Affiliate Link - Last updated prices on 2025-03-17 / Picture source: Amazon affiliate program

Radiator valves without matching adapters

IMPORTANT: Adapters are necessary for the following valve types, but there are currently no suitable adapters!

If you have other information and know of suitable adapters, please post it in the comments. I will then add to the list.

The list is in alphabetical order.

Suggested solution: If there are no adapters for your valves, the only option is usually to replace the valves. However, this can easily be done by a specialist company in your region.

Albert Ventile – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Albert	M30 x 1,5	43	38,1	NOT AVAILABLE

Armal Ventile – M24 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Armal	M24 x 1,5	15	11,5	NOT AVAILABLE

Bianchi valves – M30 x 1.5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Biachni	M30 x 1,5	10,4	9	NOT AVAILABLE

BRV Valves – M30 x 1.5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
BRV	M30 x 1,5	9,5	7,4	NOT AVAILABLE

Caleffi Valves – 23 mm

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Caleffi	23 mm	16,6	13	NOT AVAILABLE

Conec Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Conec	M30 x 1,5	9,4	6,3	NOT AVAILABLE

Coterm Valves – M28 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Coterm	M28 x 1,5	18,4	15,8	NOT AVAILABLE

Danfoss FJVR Valves – 32 mm with 2 notches

The Danfoss FJVR is a return temperature limiter (RTL valve) for floor heating systems. As they measure the temperature directly at the return and not the room air temperature, electronic radiator thermostats cannot be used for these valves.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Danfoss FJVR	32 mm with 2 notches	14,5	12,5	NOT AVAILABLE

Drayton Valves – M27 x 1.0

Note: No adapter is required for the Drayton M30 x 1.5 according to the factory standard. You will find this in the section “Radiator valves – no adapter required!“.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Drayton	M27 x 1,0	4,5	1,6	NOT AVAILABLE

ITT DGC Valves – M30 x 1.0

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
ITT DGC	M30 x 1,0	8,1	5,1	NOT AVAILABLE

Landis & Gyr Valves – 24 mm

Officially, there are no adapters for Landis & Gyr valves, although they are widely used. In the following instructions, Drewitz describes how an adapter for a Landis & Gyr valve can be converted from a RAVL adapter. Many thanks Drewitz!

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Landis & Gyr	24 mm	11	9	NOT AVAILABLE

MAW Valves – M33 x 2,0

Officially, there are no adapters for MAW M33 x 2.0 valves. However, since the dimensions of the Rossweiner M33 x 2.0 are very similar, the Rossweiner adapter could fit. Click here for the Rossweiner M33 x 2.0 adapters.

Call: If anyone here has positive experience with a Rossweiner adapter on a MAW valve, please post in the comments.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
MAW	M33 x 2,0	9,3	7,2	NOT AVAILABLE

---

Meges Valves – M27 x 1.0

Note: There is an adapter for the Meges M38 x 1.5. Click here for the adapter for Meges M38 x 1.5 valves.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Meges	M27 x 1,0	8,1	5,1	NOT AVAILABLE

Oreg/Ondal Valves – 33 mm, 12 notches

Note: There is an adapter for the Ondal M38 x 1.5. Click here for the adapter for Ondal M38 x 1.5 valves.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Oreg / Ondal	33 mm, 12 notches	7,3	5	NOT AVAILABLE

Orkli Valves – M28 x 1.5 and M30 x 1.5 with 4 prongs each

Note: There is an adapter for the Orkli M28 x 1.0. Click here for the adapter for Orkli M28 x 1.5 valves.

Note: No adapter is required for the Orkli M30 x 1.5 according to the factory standard. You will find this in the section “Radiator valves – no adapter required!“.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Orkli	M28 x 1.5 with 4 prongs	16	13,5	NOT AVAILABLE
Orkli	M30 x 1.5 with 4 prongs	12,4	10,5	NOT AVAILABLE

Polytronic valves – M34 x 1.5 and M34 x 1.5 (plastic thread)

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Polytronic	M34 x 1,5	9,1	6,4	NOT AVAILABLE
Polytronic	M34 x 1.5 (plastic thread)	7,7	4,6	NOT AVAILABLE

Pruss Valves – M40 x 1.5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Pruss	M40 x 1,5	20,5	18,5	NOT AVAILABLE

RM-Technik Valves – M30 x 1.0 (internal thread)

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
RM-Technik	M30 x 1.0 (internal thread)	4,2	1.1	NOT AVAILABLE

Rotex Valves – 25.8 mm and M30 x 1.0

The Rotex company is now part of the Daikin Group and no longer has its own radiator valves or thermostatic heads in its product portfolio.

Note: For the Rotex M30 x 1.0 valve, there were matching adapters in the past (EAN 4024052536818), but these have disappeared from the market. With a bit of luck, you might find a suitable adapter on eBay*.

As you can see in the pictures below, the plastic thread can break out when the old thermostats are dismantled. So caution is advised here.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Rotex	25.8 mm plastic	13,4	11,6	NOT AVAILABLE
Rotex	M30 x 1.0 plastic thread	– 0,5	– 4	NOT AVAILABLE

---

Samson Valves – 29,5 mm, 20 notches

This is a Samson Robinet 2035 valve.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Samson Robinet 2035	29 mm, 20 notches, M23 internal thread x Ph 4.5 P 1.5	1,3	-2	NOT AVAILABLE

Samson Valves – Robinet 2034

This is the Samson Robinet 2034 valve. I have hardly any information about this Samson valve. I only know that the connection has a diameter of approx. 23.9 mm and that the valve should be approx. 30 – 40 years old.

Call: If anyone here has more information about this Samson valve, please post it in the comments. I will add this here.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Samson Robinet 2034	approx. 23.9 mm	–	–	NOT AVAILABLE

Sarco Valves – M32 x 1.0

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Sarco	M32 x 1,0	-21,8	-24,3	NOT AVAILABLE

Scapi Valves – M34 x 1.3

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Scapi	M34 x 1,3	1,9	-0,7	NOT AVAILABLE

Sorpac /SAR Valves – M34 x 1.3

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Sopac	M35 x 1.75 (internal thread)	12,8	10,8	NOT AVAILABLE
Sopac	M35 x 1.75 (internal thread)	13,4	11,3	NOT AVAILABLE

Temset Valves – 28 mm

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Temset	28 mm	10	7,8	NOT AVAILABLE

Vaillant Valves – M42 x 1.5

Note: There is an adapter for the Vaillant 30/ 30.5 mm. Click here for the adapter for Vaillant 30/ 30.5 valves.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Vaillant	M42 x 1,5	24,6	23	NOT AVAILABLE

Valvex Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Valvex	M30 x 1,5	8	7	NOT AVAILABLE

Zentra Valves – M40 x 1,0

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Zentra	M40 x 1,0	9,4	6,9	NOT AVAILABLE

Adapter for valves with thread size M40 x 1.5

Update: 27.09.2021: Many thanks to Ruben for his comment (at haustechnikverstehen.de). According to this, it is possible to have a suitable adapter printed with the valve size M40 x 1.5 via a 3D printer service. The price is about 20€ including shipping. You can find the appropriate form on Thingiverse here.

Update 11.02.2021: Unfortunately, the VA 80 adapters do not fit valves with thread size M40 x 1.5. Many thanks to Harald Friis and Michael Peter for their advice in the comments.

Braukmann Ventile – M40 x 1,5

The Braukmann radiator valve with a 40 mm union nut is no longer manufactured today, but is still widely used. The following figures show you what a Braukmann radiator valve M40 x 1.5 looks like.

Note: No adapter is required for the Honeywell Braukmann M30 x 1.5. You will find this in the section “Radiator valves – no adapter required!“.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Braukmann	M40 x 1,5	–	–	NOT AVAILABLE

Note: The following VA 80 adapter is mainly offered as an adapter for actuators of underfloor heating systems. In this document from Siemens, however, I discovered that it can be used without any problems for radiator valves with a thread size of M40 x 1.5.
Quote: “The enclosed adapter ring (VA 80 – M40 x 1.5 mm) is suitable for valves from: Siemens, Braukmann, Danfoss, Dumser, Heimeier, Herb, Honeywell, MNG, Onda, Oventrop, Reich, Schlösser.“
The adapter may also fit Pruss with thread dimensions M40 x 1.5.

---

Oventrop Valves – M40 x 1.5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Oventrop	M40 x 1,5	19	15,6	NOT AVAILABLE

Note: The following VA 80 adapter is mainly offered as an adapter for actuators of underfloor heating systems. In this document from Siemens, however, I discovered that it can be used without any problems for radiator valves with a thread size of M40 x 1.5.
Quote: “The enclosed adapter ring (VA 80 – M40 x 1.5 mm) is suitable for valves from: Siemens, Braukmann, Danfoss, Dumser, Heimeier, Herb, Honeywell, MNG, Onda, Oventrop, Reich, Schlösser.“
The adapter may also fit Pruss with thread dimensions M40 x 1.5.

---

Radiator valves – no adapter required!

No adapters are necessary for the following radiator valves, as they have the M30 x 1.5 thread according to the factory standard:

Carlo Poletti Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Carlo Poletti	M30 x 1,5	14,1	11,7	NOT NECESSARY

Comap / SAR Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Comap / SAR	M30 x 1,5	13,9	11,5	NOT NECESSARY

Diamond Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Diamond	M30 x 1,5	13,6	11,3	NOT NECESSARY

Drayton Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Drayton	M30 x 1,5	13,5	11,4	NOT NECESSARY

Gampper Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Gampper	M30 x 1,5	15,3	11,9	NOT NECESSARY

Heimeier Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Heimeier	M30 x 1,5	13,5	11,7	NOT NECESSARY

Honeywell Braukmann Ventile – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Honeywell Braukmann	M30 x 1,5	14	11,5	NOT NECESSARY

Idmar Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Idmar	M30 x 1,5	15,1	11,7	NOT NECESSARY

IVAR Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
IVAR	M30 x 1,5	14,3	11,6	NOT NECESSARY

Jaga Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Jaga	M30 x 1,5	14,7	11,7	NOT NECESSARY

Junkers Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Junkers	M30 x 1,5	15,1	11,5	NOT NECESSARY

Luxor Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Luxor	M30 x 1,5	13,8	11,6	NOT NECESSARY

MNG Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
MNG	M30 x 1,5	14,6	10,9	NOT NECESSARY

Orkli Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Orkli	M30 x 1,5	12,4	10,5	NOT NECESSARY

Oventrop Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Oventrop	M30 x 1,5	14,5	11,4	NOT NECESSARY

Pegler Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Pegler	M30 x 1,5	13,2	11,3	NOT NECESSARY
Pegler	M30 x 1,5	13,3	11,4	NOT NECESSARY

R.B.M Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
R.B.M	M30 x 1,5	15,7	11,5	NOT NECESSARY

Rossweiner Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Rossweiner	M30 x 1,5	13,7	11,7	NOT NECESSARY

Schlösser Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Schlösser	M30 x 1,5	14,2	11,3	NOT NECESSARY

Siemens Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Siemens	M30 x 1,5	13,1	11,2	NOT NECESSARY

Simplex Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Simplex	M30 x 1,5	13,7	11,8	NOT NECESSARY

Tiemme Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Tiemme	M30 x 1,5	13,8	11,4	NOT NECESSARY

Valf Sanayii Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Valf Sanayii	M30 x 1,5	15,4	12,1	NOT NECESSARY

Watts Valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Watts	M30 x 1,5	13,8	11,1	NOT NECESSARY

Yorhe Valves- M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Yorhe	M30 x 1,5	14,8	12,2	NOT NECESSARY

Conclusion

The valve jungle is almost impenetrable, but this overview should cover most valves and their adapters. I do not assume any liability for the completeness and correctness of the information. If you have any questions, suggestions or criticism, I look forward to your comments.

Greetings! Martin

Further links and sources:
Overview Valve adapter für En:Key – Kieback&Peter
Compatibility of electronic radiator thermostats with commercially available radiator valves – EQ-3
Data sheet for thermostatic heads – Heimeier
Overview Moehlenhoff Valve adapter
Siemens Valve Actuator – Adapter VA 80 – M40 x 1,5

Picture material: Many thanks to Kieback&Peter and eQ-3 AG/Staudigl for the radiator valve illustrations provided. Also many thanks to the many images in the comments that enrich this database.