taco multi pump controller

clammy

Just wondering if any one has had this experence with taco circ panels .I recently had a low water cut off that was off but the burner would still operate on the low limit bad thing upon futher investgation i found the from the ZR and ZC termanls i believe ZC was back feeding 110 to the b1 termanal of the honeywell 8124 .For some reason i had wired the lwco to break l10 v on the 8124 but the backfeed from ZC and ZR cycled the burner on the low limit .To correct i just re wired the lwco to break the 110 from the switch .I all most always do wire them to break all power but this time the zone panel and switch was on the other side on the boiler room and i didn,t think zc or zr would backfeed through the 8124 and cycle the burner after correcting all is fine and the lwco now does shut the whole set up off good thing the probe was dirty and had cycled off thus perventing any bigger promblems .One thing for sure you can learn something new every day you just got to open your eyes and lok . peace

Joe Mattiello

Taco, Switching Relay, and ZR terminal

Good Morning
Taco SR boards do have ZC/ZR terminals to interface with a Honeywell L8124 Triple Aquastat. SR boards also have a low voltage endswitch to energize the boiler when any zone calls for heat. When using ZC/ZR terminals, and a low water cutoff switch killing power to L1/L2 you should include the SR board on the same circuit, or as you found out ZR will have 120V whenever a thermostat closes on temperature fall. Incidentally, if you were working, on the boiler with the main power off and a thermostat closed, ZR would fire the boiler. I recommend using the XX, to TT using low voltage 14 gauge wires, as opposed to ZC/ZR.



Joe Mattiello
Technical Support Services
Tel. 401-942-8000 X 484
Fax. 401-942-2360
joemat@taco-hvac.com