Missing Link

I have a D12L Espar. Last year it was sent out for general maint. . This was performed by the Espar dealer in R.I.USA. After 2 weeks of operation the heater work fine but when it reaches set temp and when it goes into cool down cycle the breaker next to glow plug pops. I reset it and the heater runs perfectly until it hits set temp. and goes into cool down cycle. (breaker pops.) After investing in having it cleaned and serviced I would like to get some use. The dealer is trying to sell me a new heater in lieu of fixing this unit. I would have considered this before they charged $ 1000.00 to service this one. They installed a new control box and glow plug. Thank you for your time.

Good morning. I have a Espar D12L. Last winter I sent it to be serviced at the Espar dealer in R.I. USA. It was cleaned ,replaced the control box and installed a new glo-plug. It fires up and runs great until it goes into the cool down cycle. The breaker next to the glo-plug pops. I reset the breaker and it fires up with no problems. The dealer is telling me to purchase a new unit after paying a grand to service this one. Do you have any thoughts on what the problem could be. Thanks for your time.