E2EB-012HA Heater w/AC - SOLVED
Posted: Tue Dec 04, 2007 1:19 am
Blower fan comes on if I turn it on manually, or have it in A/C mode, but not in heat mode. Tested for 240 volts AC on sequencer at M1-M2, M3-M4, M5-M6, got nothing. Assumed this meant bad sequencer, as did get 24 vAC on H1-H2, H3-H4.
Replaced sequencer, same situation is occurring. Have been watching voltages with t-stat set to heat, and 85 degrees. Noticed that it appeared the power to the sequencer appears to come through the heating coils first, and then into the sequencer. Getting voltage to the limit switch on one side, and when it clicks on, I do get voltage on the other sides, appearing to go into the box behind it, and into the heater coils. They don't stay on very long (about 10 second), I see them glowing red-hot from some holes into the box, and it clicks off, at which point the voltage drops. (Should they glow red-hot, or is this abnormal?) On the other side of the coils, which connects to the sequencer, and from what I can tell should also read 240v, I usually get in the millivolt range (nothing). I think I have seen it get to around 120 volts, but its hard to tell if my voltmeter was just saying 120millivolts, instead of volts at the time.
I checked for a short to ground on all four terminals of the heating coils, discovered none, and got about 9.2 ohms of resistance between each side, on each coil.
I pulled the wires off the limit switch one pair at a time, and got continuity between them while it was cold. This makes sense, as I saw 240 volts on one side after it had clicked on, it just only lasted a couple of seconds before it went off.
I tested the relay (even though I assumed it was okay since I got 24v at the sequencer), and I got 240v and 24v on their respective sides.
At this point, I figure its either got to be the heating coils, or the limit switch.
Mark Scott
Replaced sequencer, same situation is occurring. Have been watching voltages with t-stat set to heat, and 85 degrees. Noticed that it appeared the power to the sequencer appears to come through the heating coils first, and then into the sequencer. Getting voltage to the limit switch on one side, and when it clicks on, I do get voltage on the other sides, appearing to go into the box behind it, and into the heater coils. They don't stay on very long (about 10 second), I see them glowing red-hot from some holes into the box, and it clicks off, at which point the voltage drops. (Should they glow red-hot, or is this abnormal?) On the other side of the coils, which connects to the sequencer, and from what I can tell should also read 240v, I usually get in the millivolt range (nothing). I think I have seen it get to around 120 volts, but its hard to tell if my voltmeter was just saying 120millivolts, instead of volts at the time.
I checked for a short to ground on all four terminals of the heating coils, discovered none, and got about 9.2 ohms of resistance between each side, on each coil.
I pulled the wires off the limit switch one pair at a time, and got continuity between them while it was cold. This makes sense, as I saw 240 volts on one side after it had clicked on, it just only lasted a couple of seconds before it went off.
I tested the relay (even though I assumed it was okay since I got 24v at the sequencer), and I got 240v and 24v on their respective sides.
At this point, I figure its either got to be the heating coils, or the limit switch.
Mark Scott