Radiant job

Brian Gentile

Wow, that looks familiar John! Haha, I guess that job gave a nice sense of accomplishment.
-Brian

John Abbott

Recent radiant job

Pictures of a medium sized radiant job in progress.

hot_rod

Nice copper work

I'm a bit confused on the piping and mixing? Are the pumps in series? A pressure bypass may be a good addition. Looks like you are pulling from closly spaced tees on a primary loop? Pumping towards the zone valves?

Is it up and running yet?

hot rod

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Michael B

ditto

those questions.

Michael Bleier
Able Distributors
www.abledistributors.com

John Abbott

Up and running

System is up and running well. It is an injection sytem controlled by a Wirsbo 212 formerly 201 which provides two reset injection temps boiler return protection etc. I have used this control (made by Tekmar) for several years with excellent results.

John

John Abbott

Tees/ direction

Whoops,
I missed the answers to your questions about the tees and direction.The tees are reverse return not closely spaced done as an experiment no ill effects yet.I am pumping towards the zone valves Taco old reliable heat motor, if it isn't broke don't fix it.I am sure the technology I am using seems a paradox.

John

hot_rod

Trying

to get it straight in my mind. I picture it as I have drawn in the top drawing? Correct?

The bottom drawing has been my method, which seperates the VS pump (hydraulicaly) from the system pump. The blend point is in the middle of the two tees on the system loop. I have done some variations of this including the VS pump on the return side. To me it seems like you system pump will just run over the VS pump? I'm always up for something different. Maybe a drawing would help me get it clear

hot rod
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Michael B

once

again i am with hr. It would appear you are not really injecting just double pumping? I am sure I am missing something...

John Abbott

Off to work

I am off towork this AM I will try to clarify with a drawing when I get back. As Dan once told me " Send me a diagram I think better on paper"

John

John Abbott

Diagram

Hot Rod,
Your method in the diagram is very similar to the one in the Wirsbo CDAM which is where mine evolved from.I used the wirsbo method on my first injection job.When laying out the second job I decided that the extra fittings in their diagram served no purpose so I eliminated the elbows and put the tees on the flat instead of bullheading them. If you look closely at your way and mine you will see that the flow is the same only the fittings are different.The picture is my third injection system using this method and they all work. I am working on another larger job now but we are only at the rough in stage now so it will be some time before I have images.
Thanks for the kind words on the copper work

John.

Bill Wright_2

I'm sure that this works temperature-wise, but ...

I wonder if you would see flow variations in the Radiant system as the VS pump ramps up and down. Piped as HR suggested, the two pumps are hydraulically de-coupled & flow in the radiant system is independent of the VS pump. But I think the two pumps would appear to be "in series" as you've shown.

The short answer is probably -- thank goodness that hydronics is so forgiving!!

And, I agree -- gorgeous copper work, you are a true craftsman who obviously takes pride in your work!

Take care,

Bill Wright
Manager, Radiant & Plumbing Systems
Weil-McLain

hot_rod

It looks

more like a Reverse Injection. With Reverse the water returned to the boiler loop will be at the same temperature as the supply to the radiant. In other words if the supply to the radiant after the mix point is, say 100 degrees, then the return to the primary loop will be this also.

With direct Injection the return to the primary loop would be the return from the radiant loops. As such with Reverse Injection you will need a much higher injection flow rate than Direct Injection. (Your injection delta T is smaller) Depending on the loads of your radiant zones, Direct may work out fine, generally under 50,000 BTU/hr loads work well, above that your injection pump requirement would increase.

Keep in mind the return temperature from the radiant is important to the formula. If for instance you installation was a staple up or plate installation, then your return temperatures may be 120 or higher. Working this against the 180 boiler supply would require a higher gpm injection rate.

It looks like you have a globe valve at the primary loop takeoff, which is important to balance this mix. Crucial to Reverse Injection is the placement of the check. This prevents back flow when the injection pump is off.

Getting back to your drawing. The close spacing of the tees is important on both the primary loop and the connection to the radiant loop. Generally no more than 4 pipe diameters. The goal is to keep that pressure drop to a bare minimun, as any pressure drop will entice temperature to the radiant loop even with the injection pump off. Of course constant circ on the radiant loop would further encourage this.

Bottom line.. if your piping method tracks the temperature accuratly, and doesn't overheat due to migration, then the mission is accomplished.

Sorry about my rough drawings

hot rod

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Michael B

I guess the

thing that I don't understand (no offense) is why use this method? We all know/understand why and how injection works so if it ain't broke...?

Michael Bleier
Able Distributors
www.abledistributors.com
"The Supplier Who Works With You"

Steve Eayrs

I question why....

not do it the old way. You are inviting pressure drop, and having to add additional check valves, balance valves, just to not have pressure drop???? Properly spaced tee's,etc. solved that problem for good, and costs less too. All this aside it is a nice looking job.
Steve