Switching Relay Help :)

A Coal stoker furnace or stove controls most operations including automatically feeding the coal. They are quite similar to any conventional oil and gas units and easily operated for extended periods of time. They commonly use rice coal but may use larger sizes like buckwheat. They can be used as primary heat, supplementary heat or have a dual set up with your existing oil/gas furnace.
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Posts: 217
Joined: Sun. Nov. 11, 2012 4:38 pm
Stoker Coal Boiler: Kaa2
Stove/Furnace Make: Keystoker
Stove/Furnace Model: KA2
Location: Perkasie Pa.

Post Tue. Jan. 28, 2014 7:55 pm

So I was forced to buy a new switching relay for my upstairs zone. I picked up a taco sr501. I am not sure if I have the wiring right, as the wiring diagram says that I should be seeing a green light all the time, but I am only seeing this green light when the boiler is getting up to temperature. Here's what I have and what I did:

This is the aquastat on my kaa2. https://customer.honeywell.com/resources/techlit/ ... 0-2061.pdf
This is the taco relay. http://www.pexuniverse.com/docs/pdf/102-169.pdf

From what I can decipher, from the aquastat I go from ZR(hot) to H (hot) on the sr01 then ZC(white) on the aquastat to N(white) on the sr 501. I then connect the white from the circulator to N on the sr501, then from 4(n/o) on the sr501 to the circulator (hot).

Does that make sense or do I have something backwards, because it sure seems so.


Posts: 1587
Joined: Wed. Feb. 04, 2009 7:13 am
Stoker Coal Boiler: Hybrid Axeman Anderson 130
Baseburners & Antiques: Sparkle #12
Coal Size/Type: Pea, Buckwheat, Nut
Other Heating: LP Hot air. WA TX for coal use.
Location: Fair Haven, VT

Post Tue. Jan. 28, 2014 9:02 pm

You need 120VAC across H & N on your SR501.

According to the SR instructions:

ZR goes to Terminal 4

ZC goes to Terminal 3 & 5

Neutral from your 120VAC supply goes to N and the white wire for circulator.

Hot from your 120VAC goes to H on SR501

Hot (or black) for circulator goes from Terminal 6 to circulator.

Sounds like you don't have 120VAC to the unit and it's backfeeding from the aquastat.

Check each wire as written and I bet you find the problem quickly, just a matter of tracing wires. It can get confusing at times with all of the connections to be made.

Good luck!
Always learning, still stupid though :D

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