Resolver - the automated complaints system. Update your location to get accurate prices and availability. Keston heating, po box 103, national avenue, kingston upon hull, hu5 4jn, united kingdom. Registered name: db heating limited trading office address: unit 10, west devon business park, tavistock, devon, pl19 9dp. Phantom gas-fired boilers employ a stainless steel water tube heat exchanger they are primarily designed for wall mounting and can be used with natural.