Underfloor Heating Advice

Freekstile

Hasn’t been working for a bit. Replaced the intake pump (on the left) as I wasn’t getting any heat to the intake manifold lines (bottom)

The system heated up well over night it seems 40C across the whole thing except the lines themselves are still quite cool and no impact to the floor but somehow both the temperatures on either side of the feeding lines are 40C and 36C respectively. Have 12 PSI feeding in and 30 coming back. I could crank close the return manifold and bring that down to 15PSI return but I assume having them open is correct

hot_rod

if both pumps are spinning , you could have an air lock that needs to be purged out

Or the black Y strainer is partially plugged

Freekstile

I cleared the Y strainer. So ill try a purging.

Do I want to do that with the output in front of the first pump @hot_rod?

archibald tuttle

my eyes are bleeding a little trying to follow what's happening there. it looks to me like this is mislabeled reverse primary secondary in that the boiler feeds are piped secondary off the floor loops but the valve that (ironically or not i don't know) says "critical" is closed so your pumps are in series, one on the feed from the boiler and one on the return.

hot rod is right you should check for air lock. albeit are those flow indicators on the feed manifold? I'm suspicious about your pressure readings. I assume you are taking the 30 psi off the combined pressure temperature gauge on the return just to the right of the dirt separator. are your reading the 12 off the very small gauge on the feed manifold. i can't see if that is a pressure or temp. gauge in the picture.

I doubt those can be independently correct because that is just downstream of your feed pump so if both pumps are on you shouldn't be seeing anything like that kind of delta. make sure both pumps are running but the best guide to circulation/bleeding, notwithstanding gauges and indicators is feeling temp. change of water and the manifolds are the easiest place to put a hand carefully to feel for the change when you engage pumps or bleed. obviously be careful of your hand if there is very hot water to be ciruclated or forced out by bleeding.

as far as purging goes looks like there is a hose outlet on the end of the return manifold. can't see where you feed water. maybe there is a PRV (pressure reducing valve) about the expansion tank? Ideally I isolate the feed from the boiler so I can purge at city water pressure and have a full pressure tee in the area of the PRV (I tee off just after the backflow preventer although purging at full pressure is an unlikely circumstance to get backflow). I've also taken to installing a dedicated pex line to an air gap at a settub or washing machine drain so I don't have to hook up a hose to purge. in any event you should be able to shutoff the blue return valve at the end of the manifold and then shut off 3 floor loops at a time and bleed the 4th one alternating until all 4 are bled. (this is all assuming that the system is standard straight water and not anti-freeze). you might also want/need to bleed back to boiler which would be most easily accomplished if there is a bleeding assembly similar to the one on the return that can installed on the right hand end of feed manifold. other wise you have to bleed through the floor loops, doable but it doesn't allow you to break down the bleeding to various portions of the system. and for the boiler side you just need to watch your pressure or expect the pressure relief may be triggered so don't leave the priceless antiques sitting on the floor.

my 2¢ for starters.

GroundUp

Open the valve in the purge tee and purge the loops- they're airlocked.

neilc

can we see a wider view showing how this picture attaches to the boiler?

what happens if you open the ball valve between the close spaced tees?