Splitting upstairs to second zone - pipe size

secutanudu

I have a 2-floor house. Radiators on the fist floor, tube&fin baseboard on the second floor. The second floor has about 25-30 feet of baseboard. Two small bedrooms and 1 small bath.

Currently I have a mono-flo system. I have a main line running around my basement, and each radiator and baseboard has a supply and return to the basement loop. The upstairs is fed with 2 loops, one for bedroom 1, and one for bath/bedroom2. Each of those is fed with monoflo tees (1"x1"x1/2").

If I put in a new circ pump at the boiler, can I reduce to 1/2" right after it to feed my new zone upstairs, or should I continue the 1" pipe for a while before reducing to 1/2"?

__________________
Andrew

Bondo

Ayuh,... How far between the 2 loops,..??
How far from the boiler is the split,..??

I'd think feeding 2, 1/2" lines, with an inch line makes common sense...

secutanudu

The two loops are right next to each other. It's weird that they didn't feed it all with one loop to start with. The return from loop A is about 6 feet from the supply to loop B...so I figured I'd just hook 'em together and make one loop that goes up, comes down, then goes up again.

A couple simple drawings (not showing the verticals, just the horizontals). The green is what I plan to change, all in 1/2".

Before:



After:

__________________
Andrew

secutanudu

Thoughts anyone?

__________________
Andrew

fitter1

I'd run 3/4 all the way including radiation.

secutanudu

Most of the piping (and all of the baseboards) are already in place...and it's all run with 1/2" off the main line.

__________________
Andrew

Jackofall1

Heres my thoughts, you need to leave the system the way it is currently piped, I say this as there isn't enough flow GPM to carry the BTU's required to heat the areas upstairs.

Without knowing the current flow rates in the (2) 1/2" feeds going to the rooms it is a guess, but by adding a pump, sure, you will increase flow, but you will also increase fluid velocity, reducing the amount of effective heat exchange happening at the tube and fin exchangers.

Mark

__________________
When its all said and done there is usually more said than done
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

beenthere

Don't cap those mono tees. run a loop on them, or you'll effect the mono system.

3/4" is fine for the 18,000 BTUs of baseboard you have.

secutanudu

I don't really understand how it would affect it (i believe you though). My plan was to just cut the mono tees out entirely that fed upstairs.

Did you mean 1/2"?

__________________
Andrew

beenthere

You can remove them completely.

Mono tees restrict flow straight through them to force water to the red, baseboard, or what ever type of heater is used. That water from the heater is then forced back into the line to continue to the next heater, etc until it returns tot eh boiler.

If you just cap them, then it decreases the amount of water that goes through them.

secutanudu

I just remember what the mono tees look like on the inside, the way they have the diverter built in (which makes them work). I understand completely now why I need to run a little loop on them or remove them.

What about the pipe size? you said 3/4" is fine...did you mean to say 1/2" is fine? Or am I misunderstanding?

__________________
Andrew

secutanudu

Can't I just get a low-speed pump since the loop will be pretty short? There is a pump on the system now, but I'll need a pump for the new zone if i want the water to go anywhere. I'm not really adding a pump, just moving part of my current zone to it's own loop/pump.

__________________
Andrew

beenthere

3/4" is what you want to use to feed those baseboards. 1/2" will be a bit restrictive.

As a mono system, they were fed series parallel, you drawing shows you want to series them, which will increase their total foot of head. So 3/4" is needed to keep that head reasonably low. So you don't need to use a high head circ, and have a noise problem.

100 foot of total equivalent length of 1/2" pipe loses 7.22 pounds of pressure at 2 GPM. That comes out to 18.22 foot of head pressure. Then you have to add in the head loss of the flow check. You would need a very high head circ to move 2GPM through a loop like you have drawn, when you include the verticals.

You would be better off making them a paralleled loop. Where you have B and C connecting with each other. It would be better to have each of them fed separately from a 3/4" pipe and returned separately to a 3/4" pipe.

Your baseboards currently are probably being fed at a rate of 1GPM. If you series the baseboards together. In order to get the same amount of heat, you will need to have 2GPM going through them. Or the second baseboard won't provide as much heat as it does now.

secutanudu

So something like this? Green pipe is 3/4", orange is 1/2":

__________________
Andrew

secutanudu

One more question. Once I do all my piping, get the circulator installed, how do I wire the zone controller to the boiler?

I have a Triangle Tube Prestige Solo 110 boiler. My current (single) zone has this zone control relay:
http://www.pexsupply.com/Argo-AR822I...witching-Relay


Seems simple enough. The top has the low voltage..input to from the thermostat, output to the boiler. Bottom has line voltage in from the breaker, out to the circulator. When the thermostat calls for heat, it sends the low voltage signal for the boiler to turn on, and sends line voltage to the circulator. At least that's how I think it works.

So can I just get another one of these controllers? Wire it exactly the same way, except to my new circulator? Do I double up the low voltage wires underneath the screw terminals on the boiler, so either zone controller can close the circuit and turn on the boiler?

__________________
Andrew