Radiant heat questions

nickybotz

So I have radiant heat installed under my tile floor in a slab all in all working pretty nice. But for some reason I have a cold spot here and there . The returns on the manifold don't seem to be as hot as the feeds . I have access to a thermal imaging camera and will post the pics here I feel like if the water was circulating more or for a longer amount of time it would probably even out. There is a tekmar thermostat with floor sensor controlling this floor. In the last picture you can see the cold spot

EdTheHeaterMan

Thermal image appears to indicate that one of the loops is not getting as much flow as the one next to it. OR if your loop is too long the warmer area is the beginning of the loop and the cooler area is the end of the loop.

What is your loop length? how long has the water been circulating when the thermal image picture was taken?

nickybotz

All loops are less then 200' 1/2 pex, the heats been on all day well at least the thermostat I never checked though maybe the loop is closed at the manifold

nickybotz

The first picture shows the manifold that feeds that floor

EdTheHeaterMan

are you saying the pic number https://us.v-cdn.net/5021738/uploads/editor/mu/9zkdozly8daa.jpg is the same as thermal pic?

if yes, then you have insufficient flow in the loop that is cooler. 200 ft is no problem. see if the manifolds have adjustable flow controls

EdTheHeaterMan

can you tell by your experience with the install that the cooler area is the end of a loop that is working fine at the beginning? OR is the cooler area its own loop?

nickybotz

It's at the beginning and the manifold does have an adjustable flow control

Gordy

What picture of the tubing layout correlates to the infrared picture?

What is the insulation detail below if any?

nickybotz

Picture number 7 it's an open basement not finished yet

nickybotz

No insulation yet

Gordy

You are positive those two loop returns are not where the cool spot is in the infrared? Sure appears to be that way.

nickybotz

Wich two loop returns are you referring to

EdTheHeaterMan

No insulation below... a big problem. the radiant heat is going down there. Long story... 6 years of oil burner service on a DIY radiant system ,and the basement was a sauna. Every year I told the customer to get the insulation finished. Also complained that the rooms above the uninsulated area were colder than the insulated areas. As part of a divorce, the house projects needed to get finished. Insulation suddenly was completed and WOW the problem rooms heated properly, POOF, like magic!

EdTheHeaterMan

So this pic shows one of the Flowmeters is different from the others? May just be the angle of the picture. You need to double-check that

hot_rod

turn all loops but the one with no flow, see if it works then. Could be an air bubble in that circuit

Or lines crossed?

Certainly you need insulation, but all loops should get about the same S&R temperatures after they run an hour or so. They should all show a temperature difference between S&R maybe not exactly the same, depending on the circuit load.

Gordy

Agree it’s a flow issue.

Is that ceramic plank style flooring, or hardwood in the IR pic

nickybotz

It's ceramic tile , the gentleman who installed the boiler and all said I possibly need a bigger pump

nickybotz

For some reason the return lines aren't getting hot

Zman

What model circ is installed on the problem loop(s). How many loops is that circ serving.

nickybotz

It's a 007 serving 3 different manifolds about 1000' on each 4 zone manifold

Zman

It looks like you have balancing valves and flow meters on the loops. What do they read?

nickybotz

They say there's flow for sure, my educated guess would be air

Gordy

What are the flow rates reading at each loop on the gauges?

Zman

nickybotz said:

They say there's flow for sure, my educated guess would be air

Air doesn't flow, it stops water from flowing.

hot_rod

The white caps on then upper manifold will shut off that circuit, are they all open? Looks like two are tightened down and two are loosened? Remove them all and the circuit is wide open.

Also on some manifold the clear plastic flow indicators on the bottom turn to adjust and balance flow, they should be backed all the way open. CCW if you face them them directly.

Gordy

CCW=Counterclockwise 😉

nickybotz

They were all open I closed them to see if I can isolate the loop in question