Receive exclusive offers before anyone else! Our aim is to ensure all our customers have the most costefficient boilers for them and that their heating system is functionally sound. Call us today at -- for a free estimate! Would you like to leave feedback about this page? Pour / cup baking soda, followed by / cup vinegar down drain plug drain, and let sit for one hour then, pour a pot of boiling water down drain repeat if necessary. Smart controls can help with that.