Three circulator system - wiring

Post Reply
 
HozkenFelter
New Member
Posts: 2
Joined: Sat. Sep. 24, 2022 6:34 pm

Post by HozkenFelter » Sun. Sep. 25, 2022 5:18 pm

Hello everyone. So, I'm really Retro_Origin but some how the spam posts from a few weeks ago got my name involved and that user name has been banned. I've emailed twice to the admin to try to resolve it, but no response. Could someone of appropriate authority look into that?

ANYWAY, my real question:
Throughout the summer I've split my home into two zones, upstairs baseboard and downstairs radiant floor heat (staple up pex). I've done a large amount of research on the piping and such, that's pretty well done. My question is about the circulator wiring. I have a primary loop, with two secondary branches (one to each zone). The primary has it's own circulator to make available the water to the secondaries. The secondaries have their own circulators, so three in total (didn't want to try to do zone valves or get involved with trying to use the primary circ to push through the zones...too much out of my league to accomplish / predict)

Initial thoughts, make primary circulator run constant (taco 007, they all are :D :D ) but I'd like to instead make it run only when the others do...heat..wear...electric...thoughts on that?

So the upstairs (baseboards) is tied into the aquastat since it will purge the boiler pretty quickly down to the low limit, and the fire is pretty slow response. So using C1 C2 for that one. The downstairs radiant will be using 120-140 degree (to be determined still) water through a thermostatic mixing valve. I don't want this triggering the boiler everytime it runs since even when the boiler hits the low limit (160) it will have plenty of time to catch up and the radiant shouldn't ever get cold water, so I don't want to run this the Zr Zc.

What are your thoughts on the best way to wire these so both secondary circ's trigger the primary loop circ? Can I run two from the C1 C2 terminals in series since they're small circ's? If I do this won't I need a diode (check valve?) on the primary loop circ line so in the case the radiant circulator also triggers the primary circulator it doesn't then backfeed and give juice to the other one?

 
User avatar
nepacoal
Member
Posts: 1696
Joined: Wed. Nov. 21, 2012 7:49 am
Location: Coal Country
Stoker Coal Boiler: Keystoker KAA-4 / "Kelly" and an EFM 520 at my in-laws
Hand Fed Coal Boiler: Harman SF-260 - retired
Coal Size/Type: Buck

Post by nepacoal » Sun. Sep. 25, 2022 6:03 pm

Use an SR503-EXP-4. It has a connection for the primary circulator... You can use the end switch on the 503 to TT on the boiler if you decide you want calls for heat to fire the boiler. Or you could leave off the TT and let it run on the low limit. Your AA130 would easily recover fast enough to run off the LL. If you're using your KA-6, it may lag when your baseboard section calls for heat.

If it was me, I'd use the 503 and connect the end switch to fire the boiler on all heat calls. It will just shut off on the high limit when the radiant zone runs.

Attachments

Taco - SR503-EXP-4 - Install Instructions.pdf
.PDF | 141.6KB | Taco - SR503-EXP-4 - Install Instructions.pdf

 
User avatar
Rob R.
Site Moderator
Posts: 17980
Joined: Fri. Dec. 28, 2007 4:26 pm
Location: Chazy, NY
Stoker Coal Boiler: EFM 520
Hand Fed Coal Stove: Chubby Jr

Post by Rob R. » Sun. Sep. 25, 2022 6:50 pm

HozkenFelter wrote:
Sun. Sep. 25, 2022 5:18 pm
Hello everyone. So, I'm really Retro_Origin but some how the spam posts from a few weeks ago got my name involved and that user name has been banned. I've emailed twice to the admin to try to resolve it, but no response. Could someone of appropriate authority look into that?
"Retro_Origin" is not banned. You can see that here: memberlist.php?mode=viewprofile&u=30296

If you are seeing something different, please private message me.


 
User avatar
Rob R.
Site Moderator
Posts: 17980
Joined: Fri. Dec. 28, 2007 4:26 pm
Location: Chazy, NY
Stoker Coal Boiler: EFM 520
Hand Fed Coal Stove: Chubby Jr

Post by Rob R. » Sun. Sep. 25, 2022 7:07 pm

There are several ways to do this. You did not mention a tankless coil, so I will assume you don't have one.

To keep things simple, I suggest running your primary circulator off C1/C2 in the triple aquastat, and running your secondary circulators with a traditional switching relay like a Taco SR503-4 (might has well have room for a third zone). You would run a wire from the end switch in the Taco relay to the TT terminals in your triple aquastat. This will run the primary circulator whenever there is a call for heat, but not if the boiler drops below the low limit. This will bring the boiler up to the high limit on every heat call, but there is a simple way to avoid having the boiler "HOT" all the time...run a low limit of 140 and a high limit of 160 or so. You will likely find that this provides plenty of heat for most of the heating season, and you will burn less coal. If you need to crank it up to 180 in January, that is easy enough.

 
User avatar
Retro_Origin
Member
Posts: 914
Joined: Sun. Feb. 21, 2021 7:46 pm
Location: Schuylkill county
Stoker Coal Boiler: 1957 Axeman Anderson 130
Coal Size/Type: Buckwheat / Pea

Post by Retro_Origin » Tue. Sep. 27, 2022 6:44 pm

Rob R. wrote:
Sun. Sep. 25, 2022 7:07 pm
There are several ways to do this. You did not mention a tankless coil, so I will assume you don't have one.

To keep things simple, I suggest running your primary circulator off C1/C2 in the triple aquastat, and running your secondary circulators with a traditional switching relay like a Taco SR503-4 (might has well have room for a third zone). You would run a wire from the end switch in the Taco relay to the TT terminals in your triple aquastat. This will run the primary circulator whenever there is a call for heat, but not if the boiler drops below the low limit. This will bring the boiler up to the high limit on every heat call, but there is a simple way to avoid having the boiler "HOT" all the time...run a low limit of 140 and a high limit of 160 or so. You will likely find that this provides plenty of heat for most of the heating season, and you will burn less coal. If you need to crank it up to 180 in January, that is easy enough.
That spurs me on to some more thinking...so the slab sensor/PID controller whatchamacall for the radiant floor has a circulator output that I can use to run that zone, I do have a SR501(?) (I know it's a single zone).

Could I use the slab sensor for the radiant, the sr501 for the upstairs and then hook up the primary to the aquastat like you suggested? The only issue I see with this is I would in essence have to have every T-T connection go into the aquastat to trigger the primary circulator? I'm trying not to buy more stuff since I do have a few different unused things currently, but not sure I see a reasonable way to have two different thermostats tied into one aquastat...

 
User avatar
Rob R.
Site Moderator
Posts: 17980
Joined: Fri. Dec. 28, 2007 4:26 pm
Location: Chazy, NY
Stoker Coal Boiler: EFM 520
Hand Fed Coal Stove: Chubby Jr

Post by Rob R. » Tue. Sep. 27, 2022 7:11 pm

If you already have an SR501, just buy a second one. You can wire them up to do what you want.

Taco has a nice wiring guide that should give you some ideas. https://www.tacocomfort.com/documents/FileLibrary/100-92.pdf

Post Reply

Return to “Stoker Coal Boilers Using Anthracite (Hydronic & Steam)”