converting from one zone to two with monoflow system

jay in NY

Ok- I've read up on this and now I have a few more questions-

1. What electrical circuit will tell primary pump to turn on? If I understand correctly the primary loop will circulate whenever any of the secondary loop circulators start. In my case I will have three total (two heat zones and an indirect water heater).

2. I have three primary to secondary Tees (all less than 5 inches apart) that take supply water off the boiler after the expension tank, air scoop, and makeup water supply. These tees have BG flow control valves on them and will feed my secondary loops. Am I correct in placing the primary circ pump so that it will be pumping away from this- and toward the boiler return and three secondard loop returns?

3. Now here is the part that you may not like- The three secondary loops have circ pumps that pump from the radiators toward the primary loop. They intercept the primary loop after the primary circ pump. From what I've read it seems that they should pump toward the radiators, but can I continue with what I have with no detrimental impact? I have never had a significant air problem in any radiators.

The primary loop is 1 1/4 pipe and the secondary loops vary from 1 1/4 copper (radiator loop), and two 1 inch copper loops radiators on one and indirect WH on the other.

Thanks again.....................

jay in NY

converting a one zone monoflow system to a two zone monoflow sys

Have a two story single family that has a 1-1/4 inch copper monoflow system feeding 11 cast iron radiators on two floors. I want to add a second monoflow loop with a dedicated circ pump to the existing NYorker CLW 4 boiler. Will be using an ARGO to control the two zones. I was going to remove the monoflow tees from the 1 1/4 inch loop and replace with strait pipe. The radiators on the first floor (5 of the 11 in the house) will be placed on their own monoflow loop which will be 1 inch copper feeding the rads. The monoflow tees will be placed on the return side of the loop for each radiator. I am doing this because the upstairs gets too warm in the winter when I am heating with the boiler only. When I use a woodstove on the first floor of the house the upstairs gets too cool as the thermostat is on the 1st floor. Does anyone have any advice on this matter?

Steamhead (in transit)

That should work fine

Consider piping the boiler primary-secondary so you won't be dumping a lot of cold water into the return. This can cause condensation in the flues which reduces the life of the boiler and chimney.

Use a good air separator, tie the expansion tank into it, and Pump Away from this point. This way you won't always have to bleed air from radiators. Ask me how I know that works.... ;-)

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

jay in NY

Thanks- I understand everything except for the part about primary and secondary piping to prevent dumping of cool water into return. Can you give me some additional info on that?

Steamhead (in transit)

In primary-secondary piping

the primary loop is the basis for the system. Heat is added to this loop by the boiler(s) and taken from it by the system connections. The actual heating or indirect zones are the secondary loops, and the boiler may be part of the primary loop or be on its own secondary loop. The latter is used when there is more than one boiler.

The tees in the primary loop that feed the secondary loops must be spaced closely to prevent ghost flow. If they are spaced too far apart, there will be enough pressure drop between them that some water will go thru the secondary loop even if the secondary circulator is off.

With this type of piping, some warm water almost always makes it past the secondary loop takeoffs and gets around to the boiler return connection. So the boiler warms up faster.

To see some pics of a very basic primary-secondary setup, look at our latest boiler replacement thread:

http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=39995&mc=2

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

jay in NY

Very clean installation shown in the link- What I have now is a black iron supply manifold coming off the top of the boiler with an air separator and the exp tank/make up water feed tied in there. A 1 1/4 BG flow control valve connects the existing loop to the supply side of the boiler. A BG circ pump runs on the return side of the boiler. I was planning on adding a second pump on the return side (I know it is better to pump away) and a second(1 inch)BG flow control valve on the supply side of the manifold where the 1 1/4 one alread exists. How would the primary/seconday system work on my system as described?

Steamhead (in transit)

Same way

it does on the one in our pics.

Your primary circ pumps away from the air separator. In the pic, the primary circ pumps in the downward direction. The secondary circs pump away from the primary loop. The one for the indirect pumps upward, and the one for the rads pumps horizontally. But all pump away from the "Point of No Pressure Change"- the expansion tank connection.

This would require a general re-piping around the boiler, but will work much better. Of couse, you'll still need a flow-check on each zone.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

jay in NY

Ok I get it now. Thank you.

Steamhead (in transit)

Answers

1- That would depend on the control system you're using. If you're using simple thermostats and relays, you'd install relays that have extra sets of "dry contacts" wired in parallel so that when any relay operates it will start the boiler. The Argo multiple-relay unit in our pic has this capability built in, that saves a bunch of wiring. In this case, the primary circ is wired to the boiler's relay as usual, and runs as long as the burner runs.

If you go to outdoor reset, the reset controller may control the primary circ independently of the burner.

2- The primary circ goes between the air scoop and the secondary takeoffs, pumping away from the scoop but toward the secondaries. The secondary tees should be arranged like this:

First tee- supply to first secondary loop. If you have an indirect hot-water heater, it should be fed from the first tee since it will require the hottest water.

Second tee- RETURN from first secondary loop, back into the primary loop.

Third tee- supply to second secondary loop.

Fourth tee- return from second secondary loop.

And so on. If you look at our pic again you will see the pipes are arranged this way.

3- You will need to move your secondary circs so they pump AWAY from the primary loop, toward the radiation or indirect. It is essential that all circs pump away. Not doing so with P-S piping can create an air or circulation problem.

If you haven't already, get Dan's book "Primary-Secondary Piping Made Easy". Click on the Shop button on the upper orange bar at the top of the page to order it.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"