Manifold Replacement - radiant floor system

DaveTT

My old Wirsbo manifolds have to be replaced (valves are sticky and one even has a stem leak). But there are no shutoff valves at the manifolds. If I close the water supply valve and open the drain valve (both near the boiler) will I get enough water out of the system so that when I unscrew the old manifold, I won't have lots of water dumping out and into the house? It is a 2 story house if that matters. What other surprises might I find in doing this?

hot_rod

Hard to say without seeing the system or some  pics

Is there tubing above the manifolds? That is the toughest water to get completely drained out 

A wet vac at your side us the best way to catch and clean up water, and suck the loops dry

Hopefully you have some good purge points at the boiler?

Dave Carpentier

Might be worth posting some pics of the system, or a diagram.
The good folk here might suggest some improvements that could be made while it's drained.

I'm going to have to do the same job soon with my old (circa 2000) Wirsbo manifold and it's valves.

DaveTT

Thank you for looking at my post. I have a couple of photos - the manifold and the valves/drains at the Weil Mclane boiler. There are 2 drain valves - black handle at bottom by the expansion tank and the blue handle at top. I would like advice on how to use these to drain the system for manifold replacement. Cold supply is on left with shutoff in top of photo. The are two isolation valves - the red at bottom and the black up above the TACO pump. There is a second manifold in upstairs above the one shown. The manifold photos shows the mess at the leaky valve stem.

hot_rod

It might be time to drain down the entire system right to the bottom of the boiler. Its a good chance there is some sludge from years of service on that cast boiler.

I would change the manifolds fill, purge and add a hydronic cleaner. Run the system up to temperature for a few hours, circulate all the loops overnight. Drain again, add good fill water, purge and add a hydronic conditioner.

You don't want that bold gritty water getting into the new manifold valves and actuator stems.