ultra return water temp

hr

I have a prototype of this flow reverser and it does in fact help these long lengths. Are you sure you have long loops and not a flow restriction at a manifold, ball valve, or kinked tube somewhere?

I agree you must pipe that boiler primary/ secondary to keep all the hydraulics getting along.

Check this link for more on long loop fixes.

http://www.pmmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2379,122299,00.html

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jc_4

return water temps for w/m ultra

is it okay to use a weil mclain ultra in the folliwing application..replacement boiler w/incorrectly installed in floor heat?....too long of tube length dicates a 60 degree temp drop to allow for reasonable pump size...any ideas or questions would be appreciated

hydronicsmike

Mike T., Swampeast MO

The Ultra (like all condensing boilers) has no low temperature limit for the return. Room temperature will however limit return temp to around 70° in "space temperature maintenance" operation.

With a 60° temp drop, that tells me that your minimum supply temperature is 130°. It also tells me that your flow is very low.

The Ultra must be installed with primary/secondary pumping/piping. This ensures that the boiler has proper flow through the HX at all times. Your flow through the boiler is likely to be much higher than your flow through the radiant floors. While the radiant floors may have a 60° temp drop, the boiler will have significantly less (you can easily calculate with known flow rates).

In this application the boiler will be operating at significantly higher temperatures (both supply and return) that if the tubing lengths were proper. You'll still get the full benefit of modulation, but you won't get the full benefit of condensing operation.

jc_4

no restrictions...........buiding owner put the tube in years ago.2-loops of 3/4" approx. 800'long each.......now i'm called in to help.........

hr

Let's start

with the heat load calc for the space. Do you have this figure. Then we can build around what you have. While not ideal 800 feet of 3/4" is much better than 800 feet of 1/2"

Do you know the on center spacing or actual square footage of the floor that has those loops in?

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