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dickandlois

Furnace Comes On By Itself

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Have Not found this listed on any of the topics.

Furnace comes on by itself.

The issue described covers a problem where the furnace will come on even when the control switch is set to OFF and the Thermostats set at the lowest setting.

The Intellitec climate controls can have a problem in the control electronics, where a signal calling for heat is generated and will start the furnace(s).

When this problem occurs there is no way to shut them down with the user controls.

There are 2 ways to turn them off buy interrupting the 12 volt supplying the improper operation:

The first is to disconnect the 12 volt power connector from the Master Control Board. This is not the temperature setting panel that one uses to set the temperature for the Furnace / AC, or modes, high / low fan or auto control.

The control board you are looking for is labeled.

Electronic Climate Control. Energy Management Unit. Master Controller.

The module is generally located near the DC Power fuse panel or AC Breaker panel.

Disconnect the power connector from the board. This will disable the Master Controller.

When disconnected you lose all control of the furnace and air conditioning.

The second step is to remove the outside cover of the furnace affected. Many Coaches have 2 or more.

Behind the cover is a power switch that powers down the effected furnace and prevents the defective signal being generated by the Thermostat(s) logic boards form starting the furnace! Replace the cover! Then reconnect the power plug you removed from the Master Controller. All other units controlled by the controller should return to normal operation.

Note! The same signal affecting a front or read furnace may very well affect the same area Air conditioner.

Should the same problem happen with the Air Conditioner(s) all you need to do is remove the connector at the master controller connector that feeds power to the control relays mounted inside the effected unit!

You may hear a clicking sound coming from the Master Controller when this failure is happening or about to take over control of a furnace, that will keep running with no way to control the setting.

The Temperature probes could cause a similar problem and by disconnecting the probe(s) will answer that question because the affected unit will stop running.

The Master Controller can also fail, but they are not the most common cause for a failed furnace / AC control problem.

R.M.

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I changed out the Electronic Climate control and the rear furnace still comes on with the panel controls off. Went out yesterday and the furnace was on and it was 85degrees in the MH. I also swapped the furnace cards, the problem is still the rear furnace.

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On 8/29/2017 at 9:38 AM, superglide said:

I changed out the Electronic Climate control and the rear furnace still comes on with the panel controls off. Went out yesterday and the furnace was on and it was 85degrees in the MH. I also swapped the furnace cards, the problem is still the rear furnace.

Superglide, Welcome to the FMCA forum !

What climate control system is in your coach?

Could you post the Make, Model and year for the group 

Rich

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