Log in

View Full Version : Intertherm mmhb 056 electric ignition furnace


nkolber
Sep 27, 2009, 03:54 PM
Getting flashing light two times-indicates that control ion lockout due to signal not received by control that inducer pressure switch not closed n time, please help! p.s recently replaced ignightor and thermostat

T-Top
Sep 27, 2009, 06:13 PM
If it's a 90% furnace make sure the condensate drain is clear. Check for restrictions in the vent pipe.

nkolber
Sep 27, 2009, 06:36 PM
Where is the drain?

T-Top
Sep 27, 2009, 06:55 PM
Is your furnace vented with metal vent or pvc pipe?

nkolber
Sep 27, 2009, 07:00 PM
Metal, it's a mobile home, checked vent on roof, does not seem to be blocked

hvac1000
Sep 27, 2009, 09:53 PM
See wiring diagram PAGE 1 on below doc. You do not have a pressure switch in that unit you have a Centrifugal Switch built into the small combustion motor/blower. This unit is a Direct Combustion burner style.

NOTE: if this unit is on LP Gas and you do not know what you are doing I highly suggest you call a professional that does. With LP gas these babies go BANG if you try and jumper out the centrifugal switch for testing purposes.

If using Natural gas it is not quite as bad but still will go bang. Just a friendly warning. The switches do stick in these small combustion motors.

http://www.centraltrailer.com/resources/furnace/cts_nordyne/nordyne_pdf/mg.mm_wiring.pdf