How to Wire 2 Zones to My Overheat Aquastat

efo141 · Post by **efo141** » Wed. Jan. 21, 2009 11:43 am

I have one of my 3 zone pump system hooked to my L4006B overheat aqustat on my coal boiler. I want to add a 2nd zone to the L4006B. I would think if I just used the same 2 tt wires to another relay, both zones will pump if either t-stat calls for heat. Anyone know the correct way to wire before I burn something out with my own idea of how it should be done. Thanks, Ed

Freddy · Post by **Freddy** » Wed. Jan. 21, 2009 12:16 pm

If you wire two zones together so they both come on as a dump zone, they will both come on when either zone gets a call from the thermostat. I suppose you might be able add a 110 volt relay that would drive a couple of S-100 relays and make it work, but it would get complicated as well as a bit costly. I'll be interested myself to see if anyone can come up with a wiring diagram & make it look easy.

slb04786 · Post by **slb04786** » Wed. Jan. 21, 2009 12:59 pm

My first thought was "diodes". I don't know if the coils for the zone controls require AC or not but if you put one diode in each line coming from the L4006 to the zones it would stop the feedback to the other zone. This would also rectify the AC voltage to a DC voltage so I am not sure about the AC/DC requirement. No pun intended to the rock band.

efo141 · Post by **efo141** » Wed. Jan. 21, 2009 1:12 pm

How about if I split the 2 wires from the L4006B, one to each relay, then tie the 2 remaining TT together with a jumper?

spotcatbug · Post by **spotcatbug** » Wed. Jan. 21, 2009 1:50 pm

Per my request to the electrician that did my boiler wiring, my dump zone opens all four of my zone valves. I was very nervous about overheating the boiler.I'm not sure how my electrician did it (can't provide wiring diagram or anything), but perhaps this will help:

He added a box of two (or maybe it was three) relays to the side of the new boiler near the overheat aquastat. The aquastat connects into that relay box instead of directly to a zone valve. The relay box then has connections to all four zone valves. It works very well. I've seen a couple overheats happen and the zones all opened up and the overheat went away very, very quickly (like 10 minutes or less).

Sting · Post by **Sting** » Wed. Jan. 21, 2009 1:58 pm

Send both signals to a cheep DPst ice cube relay and the pumps will run when called to dump - but remain isolated for individual zone calls.

efo141 · Post by **efo141** » Wed. Jan. 21, 2009 2:16 pm

DPst ice cube relay? Thanks Sting but you lost me there, could point me to a website that sells them? Remember, I know just enough to be dangerous.

Freddy · Post by **Freddy** » Wed. Jan. 21, 2009 3:56 pm

Good thinking Sting! That's the simple answer. A double pole single throw (dpst) relay. Ice cube refers to what they look like. If you go to any electronic type shop they should sell them. Just make sure the one you buy will handle the amps of the pumps.

http://www.factorymation.com/s.nl/sc.2/category.9 ... HgodSH9Tmw

efo141 · Post by **efo141** » Wed. Jan. 21, 2009 4:11 pm

Ok, thanks guys.
ED