Aquastat L8148E, no voltage to burner *** Solved

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Old 11-22-20, 08:36 PM
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Thumbs up Aquastat L8148E, no voltage to burner *** Solved

I want to thank everyone on this DIY site. By reading your posts, I was able to solve my furnace problem, and therefore I wanted to post my own experience so perhaps others will benefit.

My trusty 20-year-old furnace with a Honeywell Aquastat L8148E decided to stop working when the weather turned cold. All the basic tests described in this forum seemed to check-out and the water circulation pump hummed, but I was not getting power on the Burner terminals. (B1,B2)

The fuse (F1) threw me for a loop. At first, I didn't even know that it was a fuse (3A). It was blown (i.e. no continuity) but if I understand it correctly, Honeywell designed it to blow after installing on a system connected to a damper. This sounds weird but it is designed so the burner only engages if the damper is connected and working.

My problem ended up being stupidly simple. There was excessive corrosion on the terminal B2 screw thread that prevented electrical connection to the burner! I believe old age and a bad flame rollout switch contributed to the corrosion. I replaced the rollout switch and cleaned the screw with alcohol, CRC 2-26, and a toothbrush.

The moral of my story - read this DIY forum then do simple continuity checks on the circuit board and wires. Again a big thank you to the DIY'ers on this forum.

 
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Old 11-22-20, 09:05 PM
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Welcome to the forums.

Good job on the repair. Glad to hear threads here were able to help you.
 
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Old 11-26-20, 06:30 PM
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For KangNJ and other DIY's here are some simple ways to make diagnostics, trouble shooting, fixing quicker and easier.

Replace old technology aquastat bulb with modern Out-DOOR-RESET-Aquastat that has LCD display of boiler water temp and settings (and can save up to 20% fuel costs). The L8148E other functions can still be used. It can power 24 VAC to Tekmar ODRA and pilot light to show Call For Heat.

https://www.supplyhouse.com/Tekmar-2...iler-4150000-p

Install modern burner control with LCD digital display of status, history of events and alarm.

https://www.supplyhouse.com/Honeywel...ic-Oil-Primary

https://www.supplyhouse.com/Carlin-Combustion-Technology-70200S-Universal-Oil-Primary-

Control-120-VAC

With those installed, KangNJ looking at boiler would have seen CallForHeat light OFF and, Burner control Status = Standby and the Tekmar water temperature reading low. Then starting question would have been why no CFH, not why boiler not firing.

Electric stack vents have switch, that until opened, prevents burner from firing. Not weird, just safety 101.

Note: Beckett GeniSys 7502 basic $70 burner control require additional purchase of $72 contractor tool for LCD display to see status and history. For total price of $142 . Even worse, GeniSys time periods are fixed, and have to buy different model for to change times.
 

Last edited by doughess; 11-26-20 at 09:23 PM.
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Old 12-12-20, 09:23 PM
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I did make another upgrade today. My 20-year-old Taco 007 water circulator started to get noisy this winter season and perhaps indicating an impending failure. I found a Taco 007e high-efficiency circulator that is a direct replacement and nearly silent. Taco claims that it uses up to 85% less electricity. It was simple to install, and I am happy with the upgrade so far.
 
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Old 12-22-20, 01:44 PM
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For many reasons, a systems circulator/pumping needs change. For an traditional $48 the benefits and features of a circulator with auto adapt pressure/flow sensing/control might be worth considering.

Taco 007E @ $128 is single speed without auto sensing. Note 007e is completely different ECM motor than old 007 synchronous motors. Taco dragged for years after buying Italian ECM motor company to introduce it.
https://www.supplyhouse.com/Taco-007...120v-60Hz-1-PH

Grundfos Alpha2 @ $176 has 7 selective speeds and auto sensing /adjustment for varying conditions.
https://www.supplyhouse.com/Grundfos...w-Terminal-Box

DH watches Grundfos Alpha2 display GPM changes as zones open and close, automatically adapting. Use Grundfos recommended "constant pressure" auto-adapt setting. With a multi zone system DH will never regress to single speed circulator.
 

Last edited by doughess; 12-22-20 at 02:34 PM.
 

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