# Radiant heat help.



## UN1TED-WE-PLUMB (Oct 3, 2012)

Ok so I get to this call today and one of the issues the customer points out is that his radiant heat in his kitchen isn't working. So at first I don't know a lot about what I'm looking at but I do my best to figure it out. The manifolds have thermometers on them and they are both at ambient temp..65*. Looks like no flow, the pump is running , t-stat is calling for heat. This is what I find. 134* below circ pump 101* above pump and 65* at manifolds. I bleed air from both manifolds until boiler pressure drops to about 5psi. I refill boiler to 20psi. Then I figure out that the blue knobs on the return manifold are actually volume controls. I play with them a little bit and figure out there is also a volume indicator. Sweet! I open them up as far as they'll go. Now my supply manifold is getting hot. I'm flowing about 1 gpm on both loops. I also play with the speed on the circ pump. It seems to give the best performance on high with the volume controls all the way open flowing about 1 gpm each. Eventually the supply is at 130* and the return is at 95*. Looking good. The floor is starting to get warm! 

My question is what is the correct temp I should have at each manifold and is there any advice you could give on something else maybe I could've done. 


When I bled the supply a bunch of black gunk came out. Also some has settled down in the gpm indicator as seen in pic below. 

I love when I get excited about a job and I actually learned a lot on this. In ready for another!


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## rjbphd (Feb 5, 2010)

UN1TED-WE-PLUMB said:


> Ok so I get to this call today and one of the issues the customer points out is that his radiant heat in his kitchen isn't working. So at first I don't know a lot about what I'm looking at but I do my best to figure it out. The manifolds have thermometers on them and they are both at ambient temp..65*. Looks like no flow, the pump is running , t-stat is calling for heat. This is what I find. 134* below circ pump 101* above pump and 65* at manifolds. I bleed air from both manifolds until boiler pressure drops to about 5psi. I refill boiler to 20psi. Then I figure out that the blue knobs on the return manifold are actually volume controls. I play with them a little bit and figure out there is also a volume indicator. Sweet! I open them up as far as they'll go. Now my supply manifold is getting hot. I'm flowing about 1 gpm on both loops. I also play with the speed on the circ pump. It seems to give the best performance on high with the volume controls all the way open flowing about 1 gpm each. Eventually the supply is at 130* and the return is at 95*. Looking good. The floor is starting to get warm!
> 
> My question is what is the correct temp I should have at each manifold and is there any advice you could give on something else maybe I could've done.
> 
> ...


Despi


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## rjbphd (Feb 5, 2010)

[QUOTE="rjbphd;364

What kind of system??? Staple up? Embedded in concrete??


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## UN1TED-WE-PLUMB (Oct 3, 2012)

In a concrete slab.


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## OldSchool (Jan 30, 2010)

Bring your supply temp down


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## UN1TED-WE-PLUMB (Oct 3, 2012)

How far?


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## rjbphd (Feb 5, 2010)

UN1TED-WE-PLUMB said:


> In a concrete slab.


Temps too high ... on very good system, you don't need higher than 110 degrees.


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## UN1TED-WE-PLUMB (Oct 3, 2012)

Could there be any negative effects of too high water temp?


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## OldSchool (Jan 30, 2010)

Infloor is built for comfort not speed


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## OldSchool (Jan 30, 2010)

Try walk on a 130 f


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## Gettinit (May 9, 2012)

What is covering (insulating) the floor. If it is tiles you can go a lot lower, same if it is a cork floor. If it were carpet in another room, you could leave it at 135°F unless the room is not close to other room temps. Remember if they are barefoot 135°F would be too hot to walk on


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## UN1TED-WE-PLUMB (Oct 3, 2012)

Its a tile floor.. So about 110* is good? What about temp differential? What is optimal? It took so long before I would get any change in temp at the manifold. They should've had temp gauges at the tempering valve it would've made it a lot easier. How much flow should something like that have?


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## Gettinit (May 9, 2012)

I would lower it to around 90-95. Just lower it a bit and have the call you to see what the temp is. You will be there adjusting all day over and under shooting.


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## karr (Dec 8, 2008)

For floor heating recommend max temp 130F, if you have big temp, its bad for floor, and noncomfortable for people foot.
About regulator i have fun, one my system work with closed regulator 1 year, when we find where heat floor not work, we change pump, we looking air on the system, we round blue caps.
When we found, what we forget, we have more fun. Realy metres is regulators.


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## OldSchool (Jan 30, 2010)

karr said:


> For floor heating recommend max temp 130F, if you have big temp, its bad for floor, and noncomfortable for people foot.
> About regulator i have fun, one my system work with closed regulator 1 year, when we find where heat floor not work, we change pump, we looking air on the system, we round blue caps.
> When we found, what we forget, we have more fun. Realy metres is regulators.


Good lord you type like you are from Russia


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## plumbny (Apr 6, 2013)

If there s black gunk ...I hope there's not a leak and ur just forcing hot water to go thru check boiler pressure with feed off


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