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:

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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

Adapter notes	Adapter*
Adapter manufacturers: Heimeier, Eurotronic (700103), various Sturdy adapter for Comap / SAR valves M28 x 1.5 from M28 x 1.5 to M30 x 1,5 Not suitable for valve radiators

Offers for Comap M28 x 1,5 Adapter

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Adapter for Danfoss radiator valves

Danfoss is one of the best known and most widely used brands for radiator valves. To date, Danfoss does not manufacture radiator valves with the M30 x 1.5 thread size according to the factory standard. For this reason, adapter sets for Danfoss RA, RAV and RAVL valves are included with almost all new electronic radiator thermostats or Smart Home solutions for heating.

Tip: By measuring the valve neck diameter, it is comparatively easy to find out which Danfoss valve it is.

Over the decades, the Danfoss product portfolio has changed so that the old Danfoss RAV, RAVL and RTD valves are no longer produced. Only the RA series has been further developed, so that today there are several series on the market that have retained the original thread dimensions of the RA valve. The difference between the respective series lies in the kvs values of the individual presetting stages. Furthermore, the latest radiator valve from Danfoss (Danfoss RA-DV – Dynamic Valve) has an internal differential pressure control, which further simplifies hydronic balancing.

Note: There are no adapters for the Danfoss FJVR because it is a return temperature limiter (RTL valve). You will find this in the section “Radiator valves without suitable adapters“.

But now it’s time for the Danfoss valves with matching adapters:

Adapter for Danfoss RA valves – 20 mm or 23 mm with 4 notches

The Danfoss RA valve has a valve neck diameter of 20 mm or 23 mm with 4 notches. It is still in production today and is the standard valve size of today’s Danfoss valves.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Danfoss RA (old)	23 mm with 4 notches	32,5	30,5	YES
Danfoss RA (new)	23 mm with 4 notches	32	30,2	YES

Thermostats without adapter: The following current Danfoss thermostats fit on the Danfoss RA:

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WICHTIG!  Bitte passt darauf auf, dass es Adapter für Ventilheizkörper und Adapter für Heizkörper mit Durchgangs- bzw. Eckventile gibt.

IMPORTANT!  Please note that there are adapters for valve radiators and adapters for radiators with straight or angle valves.

Adapter notes	Adapter*
Adapter manufacturers: Heimeier, Eurotronic (700101), various Sturdy adapter for Danfoss RA valves from Danfoss RA to M30 x 1.5 IMPORTANT: not suitable for valve radiators

Offers for Danfoss RA Adapter

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Adapter notes	Adapter*
Adapter manufacturer: Heimeier, various Sturdy adapter for Danfoss RA valves from Danfoss RA to M30 x 1.5 IMPORTANT: suitable for radiators with valves

Below you will find a short video description of the installation of Danfoss RA valves (in German).

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Adapter for Danfoss RAV valves – 34 mm with 4 notches

The Danfoss RAV valve is no longer produced today, so it should only be found in older buildings. The Danfoss RAV valve has a valve neck diameter of 34 mm. To find out if it is a Danfoss RAV valve, the valve neck diameter can be determined or a comparison of matching thermostats can be made.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Danfoss RAV	34 mm with 4 notches	15,7	12,5	YES

Thermostats without adapter: The following current Danfoss thermostats fit on the Danfoss RAV valve:

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Adapter notes	Adapter*
Adapter manufacturers: Heimeier, Eurotronic (700104), various Stable adapter for Danfoss RAV valves (neck inner diameter: 34 mm) from Danfoss RAV to M30 x 1.5 IMPORTANT: not suitable for radiators with valves

Offers for Danfoss RAV Adapter:

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Adapter for Danfoss RAVL valves – 26 mm with 4 notches

Like the Danfoss RAV valve, the Danfoss RAVL valve is also no longer in production. The valve neck diameter of the Danfoss RAVL is approx. 26 mm. To find out whether it is a Danfoss RAVL valve, the valve neck diameter can be determined or a comparison of matching thermostats can be made.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Danfoss RAVL	25.5 mm or 26 mm with 4 notches	14,7	11,9	YES

Thermostats without adapter: The following current Danfoss thermostats fit on the Danfoss RAVL valve:

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Adapter notes	Adapter*
Adapter manufacturers: Heimeier, Eurotronic (700099), various Stable adapter for Danfoss RAV valves (neck inner diameter: 34 mm) from Danfoss RAVL to M30 x 1.5 IMPORTANT: not suitable for valve radiators

Offers for Danfoss RAVL Adapter:

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AdAdapter for Danfoss RTD valves – M30 x 1,5

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Danfoss RTD	M30 x 1,5	22,9	21,1	JA

Note for Danfoss own products: Ok, now it gets a bit complicated. Apparently, the Danfoss RTD valve was hardly ever installed in Germany, but frequently in Austria and other countries.

When you buy a Danfoss product today e.g. Danfoss Eco 2.0*, there is always an adapter set for different valve types included in the delivery. However, Danfoss differentiates here between “Package for installers” – these only have the RA and M30 x 1.5 adapters in the scope of delivery – and “Package for sale”, which are country-specific. If you buy a package, it may contain a suitable adapter for the Danfoss RTD valve (Danfoss Adapter 014G0253). The emphasis is on may, because Danfoss sends different adapter sets to different countries and in the many online shops they do not always pay attention to the country codes.

For Danfoss Eco 2.0, the adapters for Danfoss RTD valves are included in the adapter sets for the countries Austria, Poland, Czech Republic, Lithuania, Latvia, Estonia, Slovenia, Hungary, Croatia, Romania, Slovakia and Ukraine. These are the Danfoss Eco versions with the numbers 014G1103 (HU, HR, RO, SK, UA), 014G1105 (PL, CZ, LT, EE, LV, SI) and 014G1109 (AT) – Source: Danfoss.

So pay attention to the country version here when buying!

In the following video you can see how such a “Danfoss RTD adapter” is mounted on an RTD valve:

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Thermostats without adapter: The following current thermostats fit on the Danfoss RTD valve:

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IMPORTANT: Only Danfoss thermostats fit on the Danfoss adapters and no thermostats with the thread size M30 x 1.5 according to the factory standard. You can find a suitable adapter for Danfoss RTD valves in the table below or under EAN 8594012221666 (thanks Drewitz for the tip):

Adapter notes	Adapter*
Adapter manufacturer: various Sturdy adapter for Danfoss RTD valves M30 x 1.5 from Danfoss RTD M30 x 1.5 to M30 x 1.5 IMPORTANT: not suitable for valve radiators

Offers for Danfoss RTD Adapter:

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Adapter for FAR valves – 23 mm with 4 notches

Note: The FAR valve has similar dimensions to the Danfoss RA valve, so you can use a Danfoss RA adapter here.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
FAR	23 mm with 4 notches	33,5	30,1	YES

Notes on the adapter	Adapter*
Adapterhersteller: Heimeier, verschiedene Sturdy adapter for Danfoss RA valves (suitable for FAR valves) from Danfoss RA / FAR to M30 x 1.5 IMPORTANT: not suitable for valve radiators

Offers for Danfoss RA Adapter:

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Adapter for Gampper radiator valves

The Gampper company was founded in 1897 by Otto Gampper in Germany and today belongs to the Afriso Group. Gampper used to manufacture radiator valves and thermostats with its own dimensions.

The most common are the two models Gampper M20 (over 10 mm depth) and Gampper M20 (up to 10 mm depth), which are visually very similar. The only difference is that the internal thread of the Gampper M20 (over 10 mm deep) is slightly stepped and that of the Gampper M20 (up to 10 mm deep) is continuous.

Today, Gampper valves and thermostats usually have the thread size M30 x 1.5 according to the factory standard, so that adapters are no longer required for new Gampper products. Suitable adapters are available for older Gampper valves.

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

Tip: Overview of all Gampper thermostats: Gampper thermostats from 1975 to today (german).

Adapter for Gampper valves – M20 up to 10 mm depth (27 mm, 4 notches)

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Gampper	M20 up to 10 mm depth (27 mm with 4 notches internal thread continuous)	11,2	9,1	YES

Adapter notes	Adapter*
Adapter manufacturer: Eurotronic (700109), various, ELV (art. no. 110216) Sturdy adapter for Gampper valves M20 up to 10 mm deep from Gampper M20 to 10 mm depth to M30 x 1.5 Internal thread continuous! Not suitable for valve radiators

Offers for Gampper M20 up to 10mm depht Adapter:

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Adapter for Gampper valves – M20 over 10 mm depth (27 mm, 4 notches)

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Gampper	M20 over 10 mm depth (27 mm with 4 notches internal thread stepped)	10,5	8,8	YES

Adapter notes	Adapter*
Adapter manufacturer: Eurotronic (700110), various, ELV (art. no. 110217) Stable adapter for Gampper valves M20 over 10 mm deep from Gampper M20 over 10 mm depth to M30 x 1.5 Internal thread stepped! Not suitable for valve radiators

Offers for Gampper M20 over 10mm depht Adapter:

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Adapter for Gampper valves – M20 up to 10 mm depth (27 mm, 12 notches)

Note: For Gampper valves M20 up to 10 mm depth (27 mm, 12 notches) the same adapters can be used as for Gampper valves M20 up to 10 mm depth (27 mm, 4 notches).

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Gampper	M20 up to 10 mm depth (27 mm with 12 notches internal thread continuous)	11,1	9,1	YES

Adapter notes	Adapter*
Adapter manufacturer: Eurotronic (700109), various, ELV (art. no. 110216) stable adapter for Gampper valves M20 up to 10 mm depth from Gampper M20 to 10 mm depth to M30 x 1.5 Internal thread continuous! Not suitable for valve radiators

Offers for Gampper M20 up to 10mm depht Adapter:

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Adapter for Gampper valves – M20 over 10 mm depth (27 mm, 12 notches)

Note: For Gampper valves M20 over 10 mm depth (27 mm, 12 notches) the same adapters fit as for Gampper valves M20 over 10 mm depth (27 mm, 4 notches). Many thanks to André Bode for sending the pictures!

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Gampper	M20 over 10 mm depth (27 mm with 12 notches internal thread stepped)	probably 11,1	probably 9,1	YES

Adapter notes	Adapter*
Adapter manufacturer: Eurotronic (700110), various, ELV (art. no. 110217) Stable adapter for Gampper valves M20 over 10 mm deep from Gampper M20 over 10 mm depth to M30 x 1.5 Internal thread stepped! Not suitable for valve radiators

Offers for Gampper M20 over 10mm depht Adapter:

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Adapter for Gampper valves – M22 up to 10 mm depth

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Gampper	M22 internal thread	–	–	YES

Call: Unfortunately, I don’t have a suitable figure for the radiator valves at hand yet. If you have Gampper valves with the M22 internal thread, I would appreciate it 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 (700111), various stable adapter for Gampper valves M22 from Gampper M22 to M30 x 1.5 Not suitable for valve radiators

Offers for Gampper M22 up to 10mm depht Adapter:

Offers Adapter for Gampper M22 up to 10mm depht:

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Adapter Giacomini radiator valves

The Italian company Giacomini produces, among other things, radiator valves and thermostats. Today, the company’s own radiator valves usually have the patent fastening “Clip Clap”, older valves have a valve neck diameter of 22.6 mm. In order to remain competitive on the market, Giacomini also produces thermostatic heads and radiator valves with the thread size M30 x 1.5.

Adapter for Giacomini valves – 22,6 mm

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Giacomini	22,6	10,6	5,4	YES
Giacomini	22,6	9,2	5,2	YES

Hinweise zum Adapter	Adapter*
Adapter manufacturers: Heimeier, Eurotronic (700105), various stable adapter for Giacomini valves 22.6 mm from Giacomini 22,6 to M30 x 1,5 Not suitable for valve radiators

Offers for Giacomini Valves 22.6mm Adapter:

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Adapter for Giacomini valves – “Clip Clap”

Alternatively, Giacomini offers its own adapter with “Clip Clap” to M30 x 1.5

Hinweise zum Adapter	Adapter*
Adapter manufacturer: Giacomini Adapter for Giacomini valves from Giacomini “Clip Clap” on M30 x 1,5 Not suitable for valve radiators

Offers for Giacomini Valves “Clip Clap” Adapter:

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Adapter for Herz Valves – M28 x 1.5

The company Herz Armaturen comes from Austria and is also very widespread in Germany. The standard thread size of Herz valves is M28 x 1.5. Herz also manufactures thermostatic heads with a thread size of M30 x 1.5.

Valve	Connection/ Thread	Open dimension [mm]	Closing dimension [mm]	Adapter
Herz	M28 x 1,5	11,2	9,3	YES

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

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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:

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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:

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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:

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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:

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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:

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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:

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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:

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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:

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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:

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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:

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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:

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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 2023-12-10 / 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 2023-12-10 / 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 2023-12-10 / 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

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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:

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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 2023-12-10 / 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:

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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