Happy Holidays! Clogged supply/return line on slab house

danitheplumber

Happy Holidays! Hope alls well!

Got a baseboard heating issue... Heat not getting all the way around on first floor… pump and prv were replaced yesterday and they tried purging but could only get a trickle... I tried purging with pulling lever on Taco prv but with in few seconds t&p would start dumping. Seems to be a blockage. Suggest added purge to return and supply after/off system to avoid t&p issue but concern with grey pipe blowing out... It's a on slab home so pipes running through concrete slab but not loosing pressure so not corroded out pipe… thought of removing prv to raise pressure but also coil starts leaking... Any help/suggestions is greatly appreciated!

Big Ed_4

You would first look for any closed valve on the heat circuit . Then you can try to back flush the loop ..

hot_rod

any way to easily isolate the circuit in the slab and blast it with city water pressure, 60 psi or so?

Putting a fill valve in to fast flow gets you more pressure, but not a lot more flow. In 3/4 copper you need about 7 gpm to get up over 5 fps velocity.

5 feet per second is when solids start to move along the tube.

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Brent H.

Not sure where you are located but could it be frozen?

HVACNUT

Both zones, or just one zone?

Pipe broke in the slab and debris caved in the hole? It looks like theirs quite a few issues there.

danitheplumber

Just the zone in slab... Been happening even after freeze and even before... In one picture you can see copper pipe slightly crimped under stair case .. but heat gets passed it so don't believe it's issue... Thinking to just disconnect return and supply and add purge valves and connect to city pressure