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Notsosuperman 02-21-2013 07:46 AM

Clicking sounds from unknown part between transformer and primary control
1 Attachment(s)
I have an Armstrong LUF80C84/95D16 oil furnace. It has a Beckett R7184B Primary Control in conjunction with a Beckett Model AFG Series Oil Burner.

Approximately a month ago I noticed a clicking sound coming from an unknown Beckett part that has several terminals (C Y G R W) with wires attached. This part is located between the transformer and primary control. Clicking comes and goes, but when it is present it is fairy constant. Sounds like you are turning a dial on a washer or dryer. The clicking only happens when the furnace is heating, and at times it causes the flame to stop and restart a minute later. It does not appear to lockout though. It also makes an odd electrical buzzing sound when the furnace is idle.

This has been going on for about a month and my landlord has been very slow to act. It wasn't until yesterday that he finally came out and replaced the filter and nozzle (that I had to end up buying to speed up the process). He heard the clicking persist afterwards but since the furnace was still running at the time tried to leave me with "Well it seems to be running. So give me a call if you have any more problems." I finally insisted that it is still faulty and he is calling the person who installed it (over two years ago) hoping that it is in warranty. Despite a working knowledge of furnaces he did not know what this part was, and thought it was a solenoid (which I don't think it is).

Anyway, any ideas as to what the problem may be, whether it poses any immediate risk (I've turned the furnace off when I'm not there), and if this is something that I can just swap out the part and fix? The part appears to be a line of terminals connecting the thermostat, primary control, furnace thermostat, and transformer. I imagine the clicking part is in fact the faulty part, but suppose it could be the furnace thermostat or transformer. Thanks in advance! I also have a video, but don't think I can post it here. If needed I can try to host it and link to it. Sorry if the picture is rotated.

beenthere 02-21-2013 04:49 PM

You can post your vid on utube and then post a link here.

techpappy 02-21-2013 05:52 PM

maybe a crack in the terminal board?..just a guess for starters..interested in learning the o' luck

Flyers28 02-21-2013 06:11 PM

It is called the A/C subase. I have seen them do exactly what you are experiencing. It needs to be replaced. There is s tiny relay in there that goes bad. Any qualified hvac contractor that deals with those primary controls or the genisys control will k ow what you are talking about.

Flyers28 02-21-2013 06:12 PM

The relay is under where it says Beckett next to the wires. The control does not need to be replaced just the subase.

Notsosuperman 03-02-2013 03:18 PM

Solved, mostly. May be due to the Nest.
1 Attachment(s)
Thanks for the comments. I think I've solved the problem. I replaced that part, which after contacting Beckett, was identified as the 51970U Terminal Base. At first I pulled it apart to see what was going on. It had a resistor (that looked a little crispy around where it connected to the board, and a relay (which was causing the clicking.) So I tried to refresh the solder under the resistor, but the problem persisted.

I ordered the new part for $35 and replaced it. After replacing it, I didn't hear any clicking, but I did hear a buzzing still that sounded fishy. So I did a little diagnostics, plugging and unplugging the Nest thermostat that I have had for a few months, and the buzzing came and went. So, with my limited knowledge of the whole system, I came to this conclusion: The Nest's power-stealing methods of rapid calls for heat on and off (faster than the furnace can respond) to charge its battery caused the buzzing sound, and eventually led to the demise of this part and caused the clicking sound.

So, I ordered 28 feet of 3-conductor thermostat wire from Lowes, duct taped it to the existing 2-conductor wire, pulled it down to the basement, and hooked it up. No buzzing, no clicking, so that problem seems solved.

Oddly enough, since adding the C wire, the Nest shows that instead of a constant period of heating to get up to the morning temperature, there are now intermittent interruptions scattered throughout. I've attached a picture to show the two days before and after the C wire. Seems odd. Reset the Nest back to defaults. I also called Nest and they had me reinstall the firmware after emailing it to me. I'll have to see if that worked. Other than confusing me, I see no ill effects. Any ideas? I'll post if it persists. My only possible thoughts would be that somehow the Nest got smarter and is intermittently shutting off the nozzle, thus saving energy, while the furnace continues to blow hot air. But I don't know if that would really save energy, and why adding a C wire would correspond with that added functionality. So, I imagine it is just a glitch.

beenthere 03-02-2013 04:17 PM

When a battery is charging, it gets warm. So when using power stealing, it warmed up the stat and kept it the heat off longer.

Notsosuperman 03-07-2013 09:30 PM

It actually does not appear to be related to the power stealing. I'm referring to the intermittent breaks of a minute or two during those big heating blocks to reach target temperature after a setback. Now that it is no longer power stealing there should be no heating up other than from the actual room temperature, and it should be a constant period of heating. I've posted on the Nest forums and a representative responded letting me know that it will be escalated to someone who will contact me. I'll post back when I find out the problem. At least the clicking is gone though.

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