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Open Trade Training Centre (OTTC) is a leading training provider of commercial and industrial refrigeration, and air-conditioning training in South Africa. Founded in 1992 by Peter and Isolde Dobelin to address the shortage of vocational skill training in the South African refrigeration and air-conditioning industry, the company’s mission is to transfer relevant technical knowledge and work skills to workers, practitioners, entrepreneurs and employers, alike.

Today, this legacy continues under the leadership of Isolde Dobelin and a highly qualified professional training team. All members of the training team are exceptionally knowledgeable professionals and have extensive local and international practical experience of the industry and its technology. Together, the staff take pride in the company philosophy of training excellence, and have tailored the courses to cover the entire spectrum of technical, theoretical and practical knowledge.

OTTC believes the quality of training must be relevant, and prepare the learner for all kinds of situations encountered in the workplace. As a result of this, the courses are not structured to purposely cover a prescribed curriculum, nor does OTTC deliberately train to prepare candidates for examinations. At the same time, the company has the advantage of not limiting its training to conform, but enjoys the freedom to include technical expertise, and skills beyond the prescribed scope, and ensures that all training aspects are fulfilled to the latest, state-of-the-art requiements.

Today OTTC is renowned for its training excellence locally, internationally and in the neighbouring countries. Close to five thousand participants have attended the popular industrial refrigeration training courses at the OTTC in Spring.


When OTTC open his doors in June 1992 Peter & Isolde Döbelin where not sure if there could make a living from training people in Refrigeration & Air-Conditioning.

Peter a German Master in Refrigeration, Heating and Air-Conditioning, Isolde Döbelin, German Betriebswirt im Handwerk (MBA for the Trades), Susanne Döbelin (tougher) 2 Years of Apprenticeship in Refrigeration employed in the successfully business of Peter Dobelin 1972 to 1982 building Heat-Pump Systems for special applications.

Together with one goal to contribute to they new home South Africa with the experience and qualifications needed changing the peoples live who have chosen the field of Refrigeration, Air-conditioning or Ammonia for there profession.

We prepared 6 theoretical and practical training courses with course books and one week duration in theoretical/practical Refrigeration including the Diploma Test.

To support his training Peter build 3 practical model plants, one Refrigeration, one Chiller plant and one Refrigeration Recovery Unit with all necessary testing Points and equipment to do Safe Handling of refrigerant incorporating the environment saving aspect and using the recommendations from UNEP.

Peter still running his own business “Combitherm” manufacturing special applications of Heatpump Systems for heating and cooling like Indoor Pools humidity controlled, Under-Floor Heating and Air-Conditioning promoting the aspects of energy saving never less power was still affordable and hi had to convince his customers for the investment on the high technology.

Isolde also still employed (1983 to 1994) by Robert Bosch (Pty. Ltd) in Johannesburg as Head of Admin for Robert Bosch Automotive Training School, Technical Publications and the Warranty System for Southern Africa.

With the help of the Refrigeration Wholesalers and Manufacturers, JL Clark, Africold, Mettek, Reco, Recam and Danfoss advertising the OTTC training we got the startup.

Not having a own training school could not stop us. We organized with the owner of the Drosty Hotel in Geduld that we could use his Conference room when needed.

The first course was held on 08-06-1992. The 5 participants was

Mr Monte Jeffreries from Marble Hall, Northern Refrigeration,

Mr Malcom Whithehouse from Marble Hall, Northern Refrigeration

Mr Mark Price from Fairview, Africold Components.

Mr Craig Hayter from Olivedale, Iceberg refrigeration.

Mr Juan Potgieter from Kibler Park, Centro Mac.

Within 18 Month 100 participants had enrolled at OTTC

The first Refrigeration Technician Diplomas was completed on 15-10-1993

The first Diploma Holder where: 

Mr John Alan Deliyiannis from Phalaborwa, Private

Mr Norman Gama from Mbabane Swaziland, Magnab’s Refrigeration

Mr Oupa victor Mkhonta from Manzini Swaziland, Ministry of Health.

Mr Victor Matsenjwa from Manzini Swaziland, Ministry of Health.

Mr Nhlanhla F Simelane from Mbabane Swaziland, Ministry of Health.

All Swaziland participants was sponsored by Magnab’s Refrigeration

In the Christmas Holidays 1993 Peter build a Class room next to our house. The building was completed to every body’s surprise when the first course started in January 1994. From then the decision was made OTTC will be a full time business. Peter and Isolde stopped working elsewhere.
1994 the first Ammonia Technician Diploma Courses was completed.

This course line was aimed at the operators of Ammonia Plants. The main problem on Ammonia Plants is safety. We would like our students to understand all aspects of the operations and feel comfortable and safe in they working environment.
Ammonia is one of the oldest Refrigerants used on very large Industrial Plants. Since then the Ammonia Courses are well known in the whole Southern Africa. We had students from Botswana, Swaziland, Malawi, Namibia even from Nigeria and Mauritius
Saudi Arabia, England and Germany.

1995 The first Air-Conditioning Technician Diploma was completed

The Success of OTTC continued. 1997 we decided to build a Training Centre.

We already had 3 residential building stands opposite our House. Then we applied for a Bond at four Banks but all turned us down. We should rent a place fro them and also there did not belief we could survive with a Training Centre. This did not stop Peter from his dream of having a proper practical and theoretical Training Centre. He put up his sleeves and started with our Gardener to dig the foundations on his own.

The whole main house of OTTC was build by Peter one Bricklayer and an Helper after hours and on weekends. On Friday we always went to Rietpan Hardware Store to get the material needed for the weekend.

In August 1998 we moved in with a big party

Joined by friends a German-Delegation from VDKF, BIV the Refrigeration Trade Association and two Master Schools in Refrigeration and Air-Conditioning.

1999 one student from OTTC Burt Bower from Kimberley, was allowed to participate in the German Apprentice of the Year Competition, he cam point equal with the second place. We also could send him to the Worldskills International Competition in Montreal, Canada where he was on place 7 out of 14 participating Country’s.
OTTC was benchmarking his training internationally.

2001 Merseta started the Learnership Programme.
OTTC was chosen to do the NQF 3 Pilot Project. 25 Learners was selected in an RPL – Prior Learning Project.

We immediately invested in 12 complete cold rooms with 12 compressors, condensers and all the equipment needed to do the practical training. Peter designed the project which included our proven Practical Refrigeration Diploma outlines.

In March 2003 the project was completed.
22 Learners graduated successfully NQF 3 Learnership in Refrigeration.

The project included the completed installation of a cold room, building there own electrical panel, commissioning and faultfinding as well as installing the Air-Conditioning Ducts and Grills with handmade Connection Boxes for the OTTC trainings hall. All the work including designing the plants was part of the program for the students in they theoretical courses.

As Peter past away on the 7 December 2002
We never consider to stop the project.

With the help of our good relationship to the Technical High School of Gelsenkirchen and the Prof. Dr. Achim Bothe which send us 2 Engineer Students for there Practicum to complete the project. Eng. Lars Wegeman now at GEA Grasso and Eng. Sven Schwarze at Kaut in Germany, started his own contracting company.

All Learners did give there best in honor of Peter.
A very big “Thank You” to them. This saved OTTC from giving up.

With further help of Susanne our daughter, Friend from Germany and by employing highly qualified Teachers we continued successfully.

2007 OTTC student Ivan Theron did win the Gold Medal in the SA Refrigeration and Air-Conditioning Technician of the Year 2007 Competition in July at the Frigair Exhibition.

2011 De Wet Brits also from OTTC did win the National Worldskills Competition.

He represented the 2011 International Worldskills Competition in London, England.

It is our goal to participate every two years in this competitions proving our self to be able to compete on international standards where +/- 28 country’s set this standards.

Of course we aim for Gold and I been sure we will get there.

Thank you to all Sponsors especially MERSETA and Dr. Raymond Patel for his hard work making this possible.

As Worldskills is only a side line for OTTC we have program’s developed for School leaver up to the top engineers in there chosen field giving them the practical side of they university education to make them employable and excel to top class engineers hunted from company’s for there skills

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