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New install radiant heat system not moving water..


biggpicc
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Please take a look at this picture and tell me what's wrong. This is a new (my first) radiant job. It's in my work shop and is made up with close to 700' of 1/2" PEX. The only 3/4" Pex is what you see in the picture. I filled the system using a 3/4hp sump pump and it filled and bled the air fine. I then tried to get the system moving with a 1/25 Grundofs circ pump and it did nothing... went out and got a 1/6th HP steibel Eltron (in picture) and that does nothing either! Even with the sump pump cranking 3/4hp during the fill the top gauge only showed 10lbs of pressure. The return gauge showed zero, however, it was moving at about 5 gal per min.

Please someone tell me how I buggered this up.

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Is there a water fill line connected to that system? Run water through the system using the fill line, and out through a short length of garden hose. Put the end of the garden hose in a 5-gallon bucket or even a trash can. As the water flows through, you will probably get batches of air bubbles periodically. Keep wasting water until all the bubbles have stopped. It can help to open and close the loops individually, run them in groups, run them all together, etc. Then try running it again using the circ. After doing this you may find that some loops flow and some do not. Purge those that do not again.

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The pump is in the wrong place and you don't have any sort of bypass. The system probably exceeds actuator close-off pressure.

Put a mixing tee on the inlet side of the pump, connect one side of the inlet tee to the return manifold, the other to a mixing valve on the hot water supply. Put a mixing tee on the outlet side of the pump and connect it to the supply manifold and to the return outlet to the boiler with a bypass line between the return outlet and the mixing valve. Put your temp gauge on the bypass.

Water that's returned through the system will be mixed with that coming from the boiler, pass through the pump and then split with part going to the supply manifold and on to the floor loops and part swinging around through the bypass and mixing valve and passing through the pump again.

I'd sketch it and post a sketch if I could but the damned scanner refuses to talk to my new windows 7 'puter so that ain't gonna happen.

If I boogered this up, don't blame me. I'm not a hydronic systems engineer. Sounds like you should have consulted one before you started.

ONE TEAM - ONE FIGHT!!!

Mike

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Kind of you to reply Chad / David. Thank you...

I do have a $7 air vent above the expansion tank, Chad. Do you recommend I relocate the air vent and put it atop an air scoop (air purger same thing)? Do you think I need the pricey Auto Air Eliminator ($88) above the new air scoop or is my $7 device suffecient?

I do have a fill valve, David. It's in the lever valve directly in front of the cir pump. I connected a hose to it and filled a bucket full of water/glycol anti-freeze mix, stuck that hose in the bucket as well as another hose in the same bucket connected to the other side of the circ pump. I closed the circ pump itself off and ran the fluid in a big loop watching all the air bubbles cione out as the fluid did ran around in circles in the closed system. I started at the last of the 5 zone valves and worked backward to the first closing each as I "thought" I got it bled. When finished I opened up the circ pump and closed off the hoses.

That's where I'm at now & I'm anxious to get back at it and try both of your suggestions. I'm really hoping to get this going since I'm in WI and it's getting close to freezing at night. Thanks guys!

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The pump is in the wrong place and you don't have any sort of bypass. The system probably exceeds actuator close-off pressure.

Put a mixing tee on the inlet side of the pump, connect one side of the inlet tee to the return manifold, the other to a mixing valve on the hot water supply. Put a mixing tee on the outlet side of the pump and connect it to the supply manifold and to the return outlet to the boiler with a bypass line between the return outlet and the mixing valve. Put your temp gauge on the bypass.

Water that's returned through the system will be mixed with that coming from the boiler, pass through the pump and then split with part going to the supply manifold and on to the floor loops and part swinging around through the bypass and mixing valve and passing through the pump again.

I'd sketch it and post a sketch if I could but the damned scanner refuses to talk to my new windows 7 'puter so that ain't gonna happen.

If I boogered this up, don't blame me. I'm not a hydronic systems engineer. Sounds like you should have consulted one before you started.

ONE TEAM - ONE FIGHT!!!

Mike

It's a closed system Mike. And yes I probably should have consulted a pro, however, I did not because I like a good challenging project.

Where would you recommend the I place the pump? I couldn't locate the exact picture I used as a reference but this one here in the link will give you a good idea. Thanks Mike

http://www.houseneeds.com/shop/HeatingProducts/heatu/tankonezonemain.asp

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Go here,

http://www.pmmag.com/CDA/Articles/Colum ... 0000132571

ONE TEAM - ONE FIGHT!!!

Mike

This is what I've got, Mike except mine is a 5 zone manifold. With its adjustment options available on both the top "feed" and bottom "return"

valves I can open or close each zone to the desired amount of flow acting much like a zone valve.

Unless I am mistaken, the picture in fig 4 on the page you sent me could be achieved by connecting a hose to the far right "drain/air bleeder" on the manifolds return and connecting it with a tee close to the feed line coming from the circ pump correct?

John

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I've already told you how I think you should configure it. Go to http://www.pmmag.com go to the archive and then search for Siegenthaler and read and absorb every hydronic system troubleshooting article he's written over the past two years and I think you'll eventually figure it out. Alternative, you could simply email the guy a picture and ask his opinion. He might answer or he might respond with something like, "I usually get paid for my consultant work."

ONE TEAM - ONE FIGHT!!!

Mike

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I'm not familiar with filling glycol systems, but I think you need to set yourself up so that you can purge a large volume of fluid through the system. Did you give it a couple of hours to purge all the air? Or maybe more? In my limited experience, non-flowing hydronic systems always mean air stuck somewhere, and more purging needed.

Kurt, I don't see an issue with loop length. A lot of systems look like his, in terms of the manifolds, and the loops are kept to <250'. He said 700 feet total, 5 loops.

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I'm not familiar with filling glycol systems, but I think you need to set yourself up so that you can purge a large volume of fluid through the system. Did you give it a couple of hours to purge all the air? Or maybe more? In my limited experience, non-flowing hydronic systems always mean air stuck somewhere, and more purging needed.

No not a couple hours David. More like a couple minutes until the visable lines were straming solid fluid. I am off to get a purger and I'll relocate the bleeder on top of it then run it for an extended amount of time. I'll then try to turn the circ pump on while the sump pump is still incorporated and is pushing the fluid through. Maybe the circ pump will take over if the fluid is moving... Kurt, I don't see an issue with loop length. A lot of systems look like his, in terms of the manifolds, and the loops are kept to <250'. He said 700 feet total, 5 loops. This is correct. Thanks again guys..

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I don't know if it's an issue......maybe it's just air.

I just think these bi-arrangements are oversimplified, and don't afford the sorts of control one may need in fine tuning the system. I am aware of some that work OK, and others not, depending on several variables.

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I think he could use the system I've described on one side of a plate exchanger and put another circulator on the water heater side. Perhaps he's using a coil-in-tank water heater so a plate exhanger wouldn't be needed.

I'm no expert either; I doubt there are any true "experts" on these systems in the ranks of home inspectors because they'd have had to come from the ranks of the radiant heating installers. With the amount of money to be made installing those systems and consulting on them, why would anyone be foolish enough to jump into this gig?

ONE TEAM - ONE FIGHT!!!

Mike

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I don't know if it's an issue......maybe it's just air.

I just think these bi-arrangements are oversimplified, and don't afford the sorts of control one may need in fine tuning the system. I am aware of some that work OK, and others not, depending on several variables. The manifold in my system allows me to open one zone more or less than the other giving me the option of how many gpm flow to each... and it works! :)

Air is all it was. As of last night it was running at around 20lbs out and 16 back in! Thanks to you guys... Kurt, Mike & David. Thank you!

What I did was add the air scoop on top of the expansion tank and got rid of the auto bleeder and went with a $6 manual bleeder. As the air enters the water heater you can easily hear it bubbling which alerts you to open the bleeder. That combined with a temporary modified version of Mikes suggestion of a mixing valve it bled in minutes.

I ran a hose from the return line on the manifold to the pail of anti-freeze on the floor. This acted like a mixing valve and the system purged quickly. Shut ALL valves leading to the temporary sump pump "pushing" the system THEN quickly shut the pump off.

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