Replacement Limit Switch

100 LIMIT SWITCH FITS TZ 8108 TEND REPLACEMENT 1NO 1NC
Paypal

US $999.99

NEW Omron Multi Plunger Limit Switch D4MB 241R Generic Replacement
Paypal

US $170.00

MJ7207L METAL LIMIT SWITCH REPLACE OMRON WLHLAL4 TS
Paypal

US $103.62

MJ7107L METAL LIMIT SWITCH REPLACE HONEYWELL 1LS10
Paypal

US $99.99

MJ7204 26 METAL LIMIT SWITCH REPLACE HONEYWELL 1LS J50
Paypal

US $74.99

MJ7208 26 METAL LIMIT SWITCH REPLACE HONEYWELL LSZ52M
Paypal

US $74.99

Replacement Limit Switch
Trane Freedom80 blows 5amp fuse when limit switch is not jumped, yet when rigged it performs fine?!?

I recently installed Ritetemp 6036 programmable thermostat, wired white-w, blue-y, green-g, red-rh as instructed by their tech support. 2 weeks later I got 4 flashes from the furnace indicating open limit switch, so I bought a new one (received same error flash Jan 17th of 09; a replacement fixed it). So I buy another switch, install it, close system and blow 5 amp fuse #1 immediately after turning furnace back on with the thermostat set to off. Old limit switch and replacement switch both tested ok by Midwest Appliance in Chi. Wires in unit look good, furnace had no recent trauma, there are no signs of mice (and I check often) and the control board isn't visibly burnt anywhere. I just cut back and reinstalled the wires in back of thermostat to no avail.... at this point I have gone through a 5 pack of these fuses and currently have the limit switch jumped, can anybody help?? Happy New Year (I hope)

Do this:

Turn off power to the heater. Remove cover panels including the bottom so as to expose the control circuit board. Get a mini flat heat or phillips screw driver and disconnect the thermostat wiring from the circuit board. Use piece of quality, (non-metallic) tape or something - to hold the (black) plastic door "button / switch" "closed". Next, at the circuit board, jumper the "24-volts" "R"- terminal screw" to the "W"- heat terminal. Leave the door panels off for now and restore main power.

1. If the 5 amp fuse blows immediately, then you have a "direct short" in the heater - somewhere in the low voltage: 24 volt circuit.

2. If the fuse does not blow and the unit continues to initiate the call for heating, then just allow it to complete the process all the way through the fan operation. Allow it to run like this for a couple of minutes then just disconnect the jumper from the circuit board and allow the heater to just time out of it's heat operation.

By doing this you've obviously taken the thermostat "wiring" and the "new thermostat" out of the equation. Finally, if the heater does end up running fine with the way I describe above, then reconnect the thermostat wires (only) to the circuit board and repeat the process all over again, but THIS TIME JUMPER THE "R" AND "W" at wires coming out of the wall with the thermostat COMPLETELY DISCONNECTED.

Last but not least, re-verify your thermostat wiring connections. Generally, if you have both heating and cooling you can get away with just 4 wires R,W,Y,G feeding the thermostat. But then you can only use either a "MECHANICAL" thermostat or a "battery powered" PROGRAMMABLE STAT. I Believe the Rite-temp you bought has both options: battery powered or if there's a 5th wire that would be 24volts "C" common to power the thermostat. If you have 5 wires coming out of the wall. R-red/24volt pwr, W-white/heat, G-green/fan relay, "y"- Yellow/cooling relay, and a "B" - BLUE this is generally used for the 24v common. SO, BEFORE YOU DO ANYTHING, FIRST DOUBLE CHECK YOUR CONNECTIONS AND WIRE COLORS AT THE CIRCUIT BOARD then be sure your thermostat is connected the same way.
Take your time and Good Luck