Manifold System for Radiators?

[Deleted User]

Demo all of the old piping and go with pex. It has been proven to work over in Europe for a long time. Buy maniflods with balancing valves on the returns. Stadler Viega has a nice stainless manifold that comes with balancing valves on it. Not that expensive either. You can zone the manifold with motorized actuators if necessary. I would use a variable speed circ also, like the Wilo ECO.

GlenJ

Radiator supply alternatives

I am upgrading my ancient oil fired boiler to a Viessmann condensing boiler. I'd like to re-plumb the radiators as well and am wondering about different methods of doing this. Would a hot supply manifold and cold return manifold with copper lines running to and from each radiator work (using ball valves to balance the supply to each radiator)? Another possibility is to run a long supply loop and a long return loop with tee's and ball valves for each radiator. I would use 1" copper for the loops with 3/4" supply and return to each rad. Do either for these systems sound feasible? I have 11 radiators to service.

Any advice or links to helpful websites would be appreciated.

kpc_33

do the manifolds...

but run pex ...pref 1/2" to each rad. I did that w/ my home w/ panel rads. 1/2"should be plenty large enough and it is easy to work w/...kpc

GlenJ

Thanks for the feedback. I'd be a little nervous about the PEX long term. Copper, although not cheap right now is proven long term and is relatively easy to install and have leak free. Does the long manifold loops idea with tee's and ball valves for each rad sound feasible?

steveex

You also have the option of zoning with individual zone valves off of the manifold in the basement, one for each room. I run up to 3 16 section sunrads from one 3/4 line in series to large rooms. If your installing new rads over size to run at lower temps, you can size the room with 50 btus per foot and run at 150 degrees for coldest days.

GlenJ

I'm working with the existing big old cast iron rads. I'm going to cut and tap the existing pipe in the basement then use brass fittings to isolate the copper from the iron (or would dielectric unions be worth the extra investment?) I'll use the ball valves for each rad to adjust the flow. I can measure the supply and return temp for each rad to help balance the flow and make sure the return water is cool enough for the condensing boiler.

Dave Stroman

PEX is the way to go. The tubing will last as long as the house does.

Dave Stroman

Rob M

Why do you put the balancing valves on the return side and not the supply side?

Dave Stroman

Dieletric unions, or even brass fittings, will not be necessary in a heating system. You never want to bury a union in the ceilings or walls.

With the mainfold system, you will find that balancing valves will not be needed. We put ball valves on the supply and the return for isolation purposes only.

Dave Stroman

Unknown

pex has been in use for decades. it's way past time to worry about it "long term".

though in a high temp app I would go for PEX-AL-PEX myself.

Unknown

you are so close to perfection.

TRVs and constant circ.