hr piping an ultra?

N.S

I have done a few just like that HR

Bob Sweet

with regards to P/S

on the Ultra, I think you've covered this before, but with regards to two temp system BB & rfh, using motorized 3-way mixing valve & I.D.W.H.
Could I pipe the two system circuits pri/sec. off the boiler loop, making it( the boiler loop) the pri. loop and the system loop as the sec. loop, or should the boiler loop stay as the sec.?
The I.D. will be piped parallel, off the boiler loop. Thanks

Tony_23

I see no problem

Piping that way and was told by a W-M factory tech that it would be okay.
As long as the primary isn't too restrictive, it shouldn't be a problem.

hr

Is this what

you mean. I use all four boiler connections when we do an indirect in parallel. You must have checks at all locations shown, and I would check BOTH sides of the secondaries to the bb and rfh.

The installation manual, also available online, shaow various pump choices for the Ultra and available head for additional piping.

I see know reason the boiler could not be within the primary loop.

Classic example as to where the PONPC should be with the indirect paralleled?
I think from the 155,000 and up ship with high head pumps, the indirect would need at least the equal circ, when parallel piped, to assure the boiler gets needed flow.

hot rod

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Bob Sweet

hr, hope this pdf comes out smaller than the last one,

here's what I was thinking. I almost got it right, the I.D. pump will be on the supply side.

hr

I would

pump that indirect INTO the boiler. The boiler likes to see the pressure increase from that circ. That's a pretty important point.

hot rod

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Bob Sweet

Thanks again hr

you are very much appreciated!! I will try that on this install.

james patrick

? for Hot Rod

I thought what mattered was flow through the boilers HX?

I think flow depends on pump head & how much resistance it faces.

I didn't think it mattered in what order the resistance is in.

Rt = R1 + R2 gives the same flow as Rt = R2 + R1 ?

Please note: All the Ultra diagrams (that I have) show the IDWH pumping away from boiler?

Thanks

hr

Pump into these boilers

because you want the boiler to see the higher pressure that the circ imparts to the fluid stream. The higher pressure indicates mechanical energy has been added to the system.

Put a gauge at the discharge side of any circ and you will see a pressure increase when the pump starts. A circ moves fluid by creating a pressure difference between the suction and discharge side.

Many of these condensing boilers have very restrictive (high pressure drop) heat exchangers, due to their original intent and design. Many started as instantanous type heaters.

The higher pressure in the boiler guards against the potential of flashing inside the heat exchanger.

If ever you need to quiet down a noisey, poping, snap crackle pop copper boiler, raise the fill pressure Often a few additional psi will keep that water from flashing to steam at the intensly hot, sometimes scaled, HX surfaces.

Pumping away from a high presure drop exchanger could also start to cavitate the circ in addition to the issues inside the HX. This is why you never want a restrictive device, like a check valve, on the inlet side of a circ. You are coaxing it closer to cavitation.

This link shows some better examples of piping for condensors.

http://www.pmmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2379,141083,00.html

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Tony_23

You're right

Flow is flow. The controls of the Ultra safeguard it from these concerns as well. I really doubt steam will be made in an Ultra I've seen what happens when the IDWH circ doesn't run under fire. The Ultra stops firing and locks out.

The W-M installation instructions ALL show the IDWH circ pumping away from the boiler. I, personally, believe it probably doesn't matter, but would not want it to be an issue if there were problems with the unit. They print those manuals for a reason