Radiant Purge Viega Manifold

jalagna

Hello, I recently added (today) a HW heating zone in my basement. After installation I bled and purged my 3 HW zones and also my 4 HW radiant zones. For some reason the return temp on the radiant is not as hot as it was prior, it’s pretty much slightly higher than room temp. Any suggestions? See picture, thanks!  

hot_rod

Is the added zone a radiant slab??  It can take some time to warm up a slab and the cold return from that zone will drag down the temperature in the other zones. Give it a day to catch up.

jalagna

The added zone was 2 Runtal elements. I had to cut into the main to add so I had to purge the other zones and I can’t seem to get the radiant zones back to hot.

hot_rod

Unless you have a purge cart with 1/2 hp pump or larger, you will need to purge one loop at a time, takes 5 minutes or so to get all the air out of long loops

Turn the blue valve off, hook a hose to the purge cock at the other end and open one zone at a time.
Either power up the actuator on the loop, or remove the actuator to open that loop. Purge, close loop, repeat on each loop of the manifold.

The cap on the purge cap has a square wrench to open the purge cock.

Stick the purge hose into the HD bucket to see when the air bubbles stop coming out.

jalagna

If I take the control heads off, how do I open and close the valve? Adjustable on the nut under the pin? 

hot_rod

When you take an actuator off the manifold that branch is now full open. When you screw an actuator onto a manifold it shuts off that port.
Until the actuator is powered up.

When the pin is up, that valve is open. Depress the pin to close off that valve.

Or leave the actuators on and power them up, to open them, one at a time.

I generally do all the purging before I install actuators.