Maple chase thermostat

A thermostat that old should probably be replaced. The newer models are programmable, and solid state instead of switches and contacts that eventually wear out.

Pull the headlamp out then replace the fuse. If it doesn't blow the fuse you new a new headlamp. If fuse blows start inspecting the wiring, it might have gotten pinched or frayed somewhere and this is causing the fuse to blow.

I sounds like either the stat is in cooling mode or you have a heat pump system and the thermostat is not configured correctly.

There is a control voltage transformer that makes 24 volts AC to operate the relays and motor contactors. The line fuses may be blown too. Check them both.

Please go to the link below for the programming manual for your EC7005PC/120 timer

Hmm. I don't think it posted the first time around. So I'll try again.

There is a temperature sensing diode on the back side of this thermostat's circuit board. This diode may have failed or become disconnected.

I'd lean towards its having become disconnected, as I've been inside an example of this Robertshaw (originally Maple/Chase) 9600 thermostat and noticed that the soldering on this part was of poor quality. So if you have a soldering iron, and know how to use it, you could probably fix it.

I have a web page (just the facts, no ads, malware or fluff) that talks of some other common problems with this thermostat and how to fix them:

http://greyghost.mooo.com/maplechase9600/

The manual is very specific.  http://www.icca.invensys.com/manuals/robertshaw/110-653B.pdf    The Robertshaw 9600 is the same unit. The terminals marked RH, RC, W, Y, G are where you put the wires, just loosen the set screws with a small flat head screwdriver, insert the bare wire into the hole and tighten the screw. Leave the jumper between RH and RC for most installations. The red wire goes to the RH. Please come back and comment if you need more specific help. Good luck

Maple chase is the same I believe.Sounds like the thermostat is bad.I personally think the Honeywell 3000-4000 series thermostat are better.But the Maple should work!

Someone did not program your thermostat to operate according to your heat and air requirements.
Have it programmed correctly.