L 8124C Aquastat doesn’t seem to be cutting circ’s

[av8042]

Hi , I Recently replumbed the entire boiler with new piping, circs , valves, tempering valve and complete feed, xtank, etc. I did remove all the circ relays and replace with a Taco SR-504-4 controller, wired as per instructions ZR-ZR on stat and ZC-ZC (pretty simple). Everything was running great, plenty of hot water,etc. I wanted to do electronics ie: aquastat, burner control, cad, etc, but before I got around to it the burner primary control went bad. After replacing it I noticed upon firing the boiler that the circs were running. One of the tests I did below low setting was I jumped out TT on the stat and checked C1 for power and it was hot. There should be no power to C1 while boiler is below low setting, correct?

 

[WorthFlorida]

Is this your aquastat? What is C1 connected to?

 

[Sponsor]

 

[Alex Vetere]

Is this your aquastat? What is C1 connected to?



View attachment 58908

Hi , No, Im testing the Aquastat for cutting out the circs at low temp. Wanted to know if how I tested it would be a good way to test it. I noticed circs were running after restarting cold boiler. Thanks, Alex

 

[WorthFlorida]

If you aquastats are the same as above, yes C1 should not have power at low temperature. Relay R is inoperable and the ZR power goes through the NC contacts B to R. One the temperature is at the minimum, Relay R operates opening contact B and closing contact W and bring power to the ZC. If you notice relay 1K2 is normally open but I could not find any info on this relay. I'm assuming it operates when power is brought to the boiler.

See page 2
http://www.fcxalaska.com/PDFs/TACO_Wiring.pdf
What are the ZC and ZR terminals on the SR506 and how are they used?
ZC/ZR terminals on the SR board go to ZC/ZR terminals on the triple aquastat with ZC/ZR terminals, using minimum 14 gauge wires. These terminals will prioritize domestic water coil. When there is a demand for heat from the thermostat, ZR becomes hot, sending 120 volts to the triple aquastat. When the boiler temperature rises above the minimum temperature setting (typically 140°), ZC becomes hot, sending 120 volts to the SR board and powering the relay for the circulators. To recap, the circulators cannot run until the boiler is keeping up with demand.

 

[Alex Vetere]

thank you, I did see the note on instructions but, before I spend $220 wanted to make sure I tested it properly, Thanks again.