Robertshaw 780-845 Ignition Module, Intermittent Pilot, 24V

Worked out perfectly.

The Robertshaw ignition module worked great and the replacement from a Lennox SP 745 was straight forward. The wire positions are not all in the same spot so you will need to make note of this as you disconnect the old module. The ignition terminal on the Robertshaw is labeled SPARK, this is the only difference for labelling. The screws that came with kit were a bit too short so I used a more suitable length. My furnace now works great again, I am very happy with the product which saved me a lot of money in the end.

It was easy to install although I had to drill a few holes on the bracket of the furnace. Just keep track of the wires and where they go.

My original Lennox furnace from 1990 stopped working and the HVAC repairman told me that my ignition board module is no longer working which is causing it to not sense the burning pilot flame thus not lighting the burners. I was quoted $500 to replace the board, fair or not, I didn't want to waste that kind of money on a furnace WAYYY past replacement life but money is very tight and I wanted to at least limp along until I can afford a new furnace. The model of my board is a Lennox SP745 and I've read that this 780-845 is the replacement for mine so I ordered it. I shut the power off to the furnace and swapped the board in 5-10 minutes. Very easy, just take note which color wire goes to what on the old board and then match it up to the new board. The only difference is that my old board had "IGN" for the spark wire and the new board had "SPARK" labeled for that. I turned it on, waited a few minutes and BAM, the burners lit and no more wearing a sweater and jacket inside the house! I will update if anything changes. **** UPDATE ***** 25 month update: Everything is still working! The only minor issue with my furnace now is that during heavy winter use the pilot light goes out once a week which then blows cold air. Luckily I just have to flip the breaker off for 10-20 seconds and the pilot re-ignites and blows warm again. I don't know if this ignition module is to blame or if it's something else on this ancient need to replace soon furnace.

I have an old Carrier 58gsc. It would start, sometimes, then stop. Wiggling the wires seemed to help so I decided the springs connector to the lockout/ignition controller LH33WZ512A had worn out. The 6-pin connector on the old controller looked hard to replace so I took a chance and ordered this controller with friendlier looking connectors. I used $7 worth of "disconnect" terminals that came with a crimping tool and it was within my capabilities. Installation notes: I didn't seem to need to hook everything up. 'PV/MV common' and 'Transformer ground' on the new controller were left floating. I connected the sense to the adjacent terminal on the controller as suggested by the instructions. From the old connector to the new controller: Black - ground Blue - Thermostat 24V Yellow - Pilot Valve White - Main Valve Brown - No connection (This floats at 24V when the furnace is on. I think it has something to do with the old flame sensing mechanism but this controller doesn't seem to need it.) I was really pleased how quickly the furnace started up. Just a few seconds; much quicker than the old controller. Also, when I turned off the gas, the controller immediately locked out until I turned the thermostat down and back up again. Seems safe. Not sure how the flame sensing works; seems like magic; but works. At one point I connected the brown wire to PV which is wrong and the controller LED blinked then shut down which was helpful in guessing the connections. I had paid some con artist $90 to quote me $650 to replace the perfectly good control valve. This box fixed my problem for $80. Great product!