I have an EKO 25 and seems it does not heat my water very fast. It takes about 2 hrs to heat my water. I don't have storage so I heat about 35 gal. of water. I have my eko 120' from the house with real good insulated pipe. My wood is at 16% mc. I have the eko super and never cleaned the tubes manually but seems nice and clean inside. Does this seem normal?