jQuery - remove select option based on text not value

you can use :contains to filter based on text content of an element, but note that it will return partial matches. So :contains('Vaillant 835') will return :contains('Vaillant 835') and :contains('Vaillant 8356')

jQuery("#select_Boiler option:contains('Vaillant 835')").remove();

If you want to filter for equal you need to do a manual filter like

jQuery("#select_Boiler option").filter(function(){
    return $.trim($(this).text()) ==  'Vaillant 835'
}).remove();

Here's the case insensitive option of Arun P Johny's answer.

jQuery("#select_Boiler option").filter(function() {
    cur_text = $(this).text().trim().toLowerCase();
    return cur_text.indexOf('Vaillant 835') != -1;
}).remove();