Lately the thermo pump breaking shot down and the furnace work on the auxilary . This is very expensive in electricity. But what can cause the breaker to keep throwing the circuit?
closed as not a real question by The Evil Greebo, Tester101♦ Jan 4 at 20:53
It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, see the FAQ.
If your thermo system is robust, the auxiliary furnace may have never been called into full demand. The circuit it's on may have been under sized all along, this is the first time it's been fully tested. Alternately, there could be a partial short causing excess current draw in the circuit.
Review the furnace specifications and determine if the circuit is adequately sized. If not, either the circuit needs to be upgraded, or a coil bank taken out of service. Which one would depend on how well it heats your home now.
If the circuit checks out, then the system will need to be inspected and the cause of the excess draw identified and corrected.