Short cycling after LP gas to Electric retrofit

[daviddon1]

I recently changed my Janitrol LP gas furnace to electric using a Coleman 9.6 KW dual heating element. I removed burners,pilot and valve but used existing 24 VAC controls and sealed unit with cover plates and aluminum tape. I installed a 60 amp contactor for the elements and a 50 amp breaker on 8 awg THHN wire. When we cut the opening for the heating element it was smaller than it should have been and shorted the element to the unit causing the breaker to trip. We removed the element and made the opening larger and the short was fixed. When unit was restarted both elements ran for 8-11 seconds then the limit switches would click and elements would power down for 30-40 seconds then come back on for another 8-11 seconds and so on. I am still getting 24 VAC at contactor. Do I need a heat sequencer and then eliminate the existing LP gas controls? Could we have weakened the L150-40 limit switches with the short circuit to the casing and they need to be replaced? How would you complete this retrofit and allow for more "on time" for the elements? Any help would be appreciated.

[Robert]

Hi,


This is not something I would do myself or recommend for anyone else to do.


Furnaces when designed take into account how they are made, airflow travel routes, etc. and then the safety match those design specs.


When you do as done here, you essentially are trying to put the workings of one into the body cavity of another and often this is result.



It can become a fire hazard, will void insurance claims if a fire occurred and therefore is not a good solution.


It has been done successfully, but not recommended, especially for DIY due to dangers from a mistake.


My best offer would be to find someone local who may be willing to look at it and advise, but not something for over the internet if at all.



Thanks for inquiring.



Take care and best wishes,
Robert