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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 5648
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Central electric furnace model eb17cx, First thanks, I have

Customer Question

central electric furnace model eb17cx
JA: Thanks. Can you give me any more details about your issue?
Customer: First thanks, my name is***** have a 2009 electric furnace with deluxe blend air II. Last night the fan and heat never turned off. Temp set for 60 and house was at 71 when I woke during the night and having no control from the thermostat I simply turned the main breakers off. This AM I went thru the filter replacement and reset on the thermostat. Nothing seems to work. I replaced the thermostat and have the exact same problem. I'm an electrical engineer (retired) so I do understand how most of the parts work and terminology.
JA: OK got it. Last thing — HVAC Technicians generally expect a deposit of about $18 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 8 months ago.
Category: HVAC
Expert:  Phil replied 8 months ago.

Hello Carl, if you can use the paper clip icon at the right end of the tool bar above your dialog box to send me a close up photo of the wiring diagram glued inside the furnace front panel, I can mark it up with trouble shooting directions.

The photo needs be taken squarely from straight on, very well lit, and focused. If you can include a photo of the terminal strip inside the furnace where the thermostat wires land that will help a lot also.

We can go from there.

Customer: replied 8 months ago.
Thanks Phil;
Sorry it took me a bit to get back with you. I needed to bring in more firewood assuming this may take awhile. I live in north eastern washington state. Below freezing at night. I attached 4 pics of the various diagrams.Carl
Expert:  Phil replied 8 months ago.

Thanks for the photo's

http://screencast.com/t/WYJYaTkLALC

We can go from there.

Customer: replied 8 months ago.
OK thanks Phil. I like measurements.Between R & C in the blend air box I get 25.7 and also the same between R & G.Let make sure we are on the same page. The blower only stops (runs constant) when the breaker is pulled (main breaker box).
Observations from test last night. I can call for heat from the thermostat. With the breaker ON the fan speed increases speed and the heating elements are ON (heat from registers) while heat is called for and then fan reduces speed when the call for heat is OFF (temp reaches set point) but never turns off (fan) regardless of any input or switch settings from the thermostat.I found another reply from one of your other experts (Matthew) describing the exact problem. (no date) on his advice. He suggested it may be the relay and or sequencer.Carl
Expert:  Phil replied 8 months ago.

Hello again Carl, There are only relays and sequencers in the control circuit as regards ***** ***** coming on and staying on, so its a pretty good guess that is one or other of those... there are 5 or 6 depending on the model you have.

The 3 photo's you sent were of the 'blend air' system, that is entirely separate from the blower controls (sequencers and relays).. that diagram is glued inside a cover about as wide as the furnace ... it is much more complex than the blend air diagram.

Your tests proved that you have 24volt control power however, when you get the other diagram to me I can mark it up with trouble shooting directions.

We can go from there.

Customer: replied 8 months ago.
Thanks Phil;
As far as I can tell slide 4 is the most compressive schematic.Carl
Expert:  Phil replied 8 months ago.

Hello again Carl, only slides 2, 3 and 5 showed up

Expert:  Phil replied 8 months ago.

either that or Im going blind

Customer: replied 8 months ago.
Sorry Phil;
Perhaps the files were too big. Here's slide 4
Customer: replied 8 months ago.
Thanks for your help Phil;I ended up replacing both the sequencer and relay. The darn thing started working normally prior to replacing parts. 2 days working fine but I'd ordered both parts already. Still working fine. I'm done for now. Carl
Expert:  Phil replied 8 months ago.

Thanks for staying in touch, you have a loose or corroded wire connection somewhere in the area, wiggle the wires gingerly ONE at a time, that often locates the culprit.

If you rate my work so far positively the company pays me half of your deposit, its how I earn a living, In exchange I will leave the question open to you for any follow up that will probably need later,