NOISY SOLAHART GEYSER

A Solahart geyser was installed at my house by Rolff van der Linden of SOLAHEAT in Nov 2015. The geyser worked perfectly and I was very happy. At the end of 2019 I requested Rolff to service the geyser as stipulated in the Owner’s manual. During the service Rolff found a stripped nut on the cast iron plate holding the element to the tank. He fixed this and tested the geyser. The geyser worked perfectly until mid January 2022 when it suddenly started making a high pitched whistling noise when any tap inside the house is opened. I contacted a local plumber who changed the Pressure Regulating Valve as well as both vacuum breakers on the geyser to no avail. The noise was persistent. I contacted Rolff on 17 Jan 2022 and explained my problem. He said I must get a plumber because he did not believe the geyser was the cause of the noise. I said that I already had a plumber and told him what was replaced. He said he would come out in the week ending 28 Jan. He did not pitch. I contacted him again on 24 Jan and once again he said I must get a plumber. On 2 Feb he sent a whatsapp saying that he would come out the next morning and that I must have R9000 in cash to pay for the call out. I live in Gansbaai which is 160 km from Cape Town. I sent a message back that I cannot pay such a huge amount for a call out. He then said I must get a plumber to clean the filter and remove the Apex thermostatic valve. I had this done, but it did not solve the problem. On 6 July I contacted Rolff again and asked if the noise could not be caused by the nut that was stripped. He said the noise cannot come from the tank and that he was in Namibia until August and that I should contact him late August. On 26 August I made a video on which the noise can be clearly heard. I sent him the video. He responded that it was strange but that he could not come out because he had a knee operation, but that he will be able to come out in 4 weeks time. On 29 September I sent him two whatsapps to which he has still not responded. I offered to pay reasonable call out and labour fees if he can just come out to site. I also contacted Solahart Industries in Australia to get Rolff out to my house, but they said that they pulled out of South Africa and sent my mail to Rolff. I do not know how to fix this problem while Rolff refuses to come to site.