I have a single zone FHW system with three loops -- two for downstairs, one for upstairs. The feeds for all three loops come off a single manifold.

I also have a spare circulator (formerly used for the hot water tank, which was replaced this summer with electric).

So, I want to take the second floor return line (this system is set up to pull) and connect it to the unused circulator to create a separate zone.

My question is -- do I need a separate check valve for the new zone? There is one check valve just before the manifold that serves all three loops.

 

Would it be possible to sketch and post a piping diagram?

The existing loops... running off of a single pump? and one thermostat fires up the system and sends heat to the entire house, all three loops?

 

Your better off using zone valves IMO... One for the new zone... Then tie those two loops to a common pipe and a zone valve there...

You will need to do a little repiping but nothing major..

When you get into using circs then you need flow controls. Piping will be more difficult...

 

I was considering zone valves.... but then I realized I'd need to buy two zone valves at $100 each and I have a free circulator just sitting there....

 

So here's a diagram (really gave my artistic skills a run for the money). What I want to do is take one of the loops (represented by L1, L2, L3) and split it off to it's own zone by running the return line to the unused circulator. There is a check valve (CV) that serves the single zone now and I'm wondering if I need a check valve for the new zone.

 

Yes you'll need a flocheck on your new zone to stop the water.flow when the other pump calls.
That's only the beginning.

If you use pumps your going to have to remove the pipe for the new zone and reattatch it before that check valve. If you leave it there the new pump will also allow flow to the others loops.
Also with pumps you'll need to buy seperate relays. At least one and maybe two depending what you you have for an aquastat.
If your control has a ZC & ZR terminals you can get away with one relay. If not you'll need two.
If you went with zone valves you'll still have to relocate your supply pipe but that's it. You can leave everything else alone.
You'll need 2 zone valves and a 24v transformer.

Since you're not getting your hot water anymore, with zone valves you don't need the flocheck anymore.
You can cut that out and put a tee for your new zone feed and then add the zone valves. You wouldn't need to touch your return side at all except to make provisions for bleeding if you don't have any yet.

 

Hmmm, you make a compelling argument for the zone valves.

But a question about the controls (I was on here earlier with a question about controlling the two circulators). I have an a L8148A aquastat. No ZC ZR terminals. What am I going to connect to that to control the valves?

 

The zone valve simply go to TT on the 8148.
The stat wire that you have on there now will go to one of the relays and your new t-stat wire will go to the other relay.
What I do is install a small box and bring the two zone valve wires into this common point and then you add another t-stat wire to the TT terminals on your 8148 and bring that also to the box and make all connections there.
It just makes for a neater job and doesn't put too many wire on a terminal.
If you have to buy the relays another way you can do this is with a Taco relay panel.
You bring in one feed and bring all wires into that.
I understand there not much more and worth it labor wise.
I know it's a Taco 501 ?.
They have these for pumps and zone valves. Make sure you get the right one.
Trooper would know the number but I'll find out in the mean time.

If you go with zone valves you won't need this anyway. One 24v transformer will do it.

 

Repipe is simple.

Add a transformer near the zone valves.

Wire the t stats to the zone valves and the zone valves to the aquastat...

Done!!!

But I dont know what one is your upstairs loop.. Pic is to show you piping.

 

OK, diagram makes sense, but now I'm confused about the wiring:
1) thermostat wires to zone valves. OK.
2) Then wires from zone valves to aquastat (to the thermostat terminals?).
3) Where does the transformer come in?

 

#2.......yes

# 3 The transformer needs to power the zone valves...



image courtesy NJ Trooper

 

Actually, I found a diagram that explains this. It looks like:

1) Tie one terminal from each thermostat to one terminal on the transformer;
2) The other terminal from each termostat goes to the #1 terminal on each zone valve;
3) The 2 & 3 terminals on each zone valve are tied together and connect to the TT terminals on the aquastat
4) The other terminal from the transformer is tied to the #2 wire from the zone valves

Correct?

 

Your zone valves are 24v so you need a transformer to power them and not the one that's in your control. That one is there strickly to turn on the boiler.

Your circuit will be :

One side of new trans. to t-stat, from t-stat to term. 1 on zone valve, term 2 on zone valve back to new trans.
Term. 2&3 on zone valve to TT on 8148.
This is for a 3 terminal Taco zone valve. If you use Honeywell it will have 4 terminals.
The process is the same.
On Taco 1 & 2 open the valve and activate an end switch and 2 & 3 activate the the burner.
On Honeywell it's 1 & 2, then 3 & 4 activate the burner.

I wish I new how to use this sight better I could draw you a diagram or post pics.

 

Thanks spott -- what you said makes sense. Zone valves it will be. And thank you lawrosa also!

 

Did you see the pic I posted in post#11
I see it possibly you fellows dont?


image courtesy NJ Trooper

 

Yes -sorry -- I think our postings are overlapping. This make sense! Thanks again for all the help -- saved me hours.

 

Larosa, thanks for the diagram. I've got to learn how to post things. It's so much easier when you see it.

 

A thought occurs... does it matter where in the loop the zone valve is placed?

 

No it doesn't as long as the piping is divided into seperate zones correctly.
Just a thought. You might want to put in some ball valves while you're down at least at the beginning and end of each zone in case of trouble so you won't have to shut down the whole house to work on one zone.