AQUASTAT not triggering with call for heat.

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Old 10-18-20, 02:59 PM
J
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Exclamation AQUASTAT not triggering with call for heat.

Finally diagnosed my heating problems to a bad Honeywell AQUASTAT L8148J (PHOTO 1) — the relay would click, but the circulator wouldn't turn on. Ordered a replacement and just installed (PHOTO 2). Turn on the system and…nothing. I physically close the relay and both the furnace and circulator come on as they should. I look over my wiring and saw I had the thermostat wire that should've been on T on W instead, correct it, turn it back on and still nothing. Figure it's the wire connecting the AQUASTAT to the zone valves, replace it, still nothing.

Frustrated, I check online and find a video that points out I should see 24v between B1 and Z — I'm only seeing 17v. (PHOTO 3) (I tested B1 to both W and T, still only 17v).

Question, do you think that A. I just got a faulty replacement or B. would the accidental wiring of the thermostat wiring cause damage that now prevents 24v from passing between B1 and Z. I'm close to calling in the professionals, but since I've come this far wanted to make sure I didn't overlook something.

Any help/insight would be greatly appreciated. Thank you in advance.

NOTE: I am reading 24v between ports 1&2 and 1&3 on my TACO power heads and the override moves freely.





 
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Old 10-18-20, 05:16 PM
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Welcome to the forums.

With the the stat not calling for heat..... there should be around 24vAC from Tv to T.
With the stat calling for heat there should be around 0v from Tv to T.

The burner is usually 120v and I see what looks like line voltage wiring connected.
But I also see thermostat wiring on the high voltage connections. What's that all about ?
(red on B2 and white on the switch)
 
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Old 10-18-20, 07:44 PM
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Thanks Pete

So when turning off the stats I have 0v between TV to T and then around 7v from B1 to Z/W/TV. Here's the video I was using when trying to identifying/reference the voltage amounts from my previous post.

Regarding the voltage wiring from B1 to the Lower Temp Gauge — it's a line (L3 IN PHOTO 4) that runs up to a secondary thermostat (PHOTO 4) that controls my 2nd floor's heat. (I do not have a Zone Valve for the 2nd floor). My guess is that it only fires up the burner when needed.

Even though the stat line is decrepit as hell, and the electrical tape scares me, this system is currently working.

 
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Old 10-23-20, 06:41 PM
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Quick update. Contacted the supplier, exchanged the relay and installed. Everything's now working as it should.
 
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Old 10-23-20, 09:59 PM
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Good to see you back up and running. Thanks for the update.
 
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