lochinvar whn pump strategy

rick in Alaska

Time for my questions now.
I am putting in a Lochinvar whn 085 into a warmboard heated house and an 80 gallon indirect. The house is 1800 square feet with a heat loss of 39,000. I ran this late last night so not sure if I got all the info right. I haven't used this heat loss program for awhile, and am sure I am missing something in the insulation detail for the crawlspace, so am pretty sure the heat loss is less. But at this point the heat loss is not so much the concern. I will work that out later.
I have been following some of the posts about piping this unit and am not sure the best way to go. It sounds to me like the best way to go to get the most out of this system is to pipe it direct. I am pretty sure I can get the customer to go with a 0-10vdc pump. The other way would be like a Taco vt2218 controlled by the zvc boxes from the manifolds.
I am not sure which will get me the best results for the system and the customers money.
The heat program I used is for Wirsbo, so it can only calculate for Quictrac, which uses 5/16" tubing, therefore the head loss is not right at this time.I will try and run it later to see if I can get better outputs.
The smallest zone will be down as low as 300 btu for a guest bath, but most likely that zone will on with the main line zone.
So, 15-58, vt2218, or 0-10vdc pump? Or, do I really need to pump it primary-secondary? Head loss doesn't seem to justify that though.
Thanks,
Rick

SWEI

The Uponor programs can do 3/8" and 1/2" tubing if you choose Joist Trak.

Rich_49

12" centers , concrete overpour has been the closest to what we actually needed on WB jobs . Fine tune using their chart for SWTs and floor coverings .

Issues Hatt describes above may not be an issue with the 10* Delta you would be designing with

rick in Alaska

Sorry. Just got in from work all day. I actually meant to say the KHN085, not the WHN, so it does go down to 8500 btu. I called Lochinvar today and the guy I talked to was not up on the 0-10vdc off the boiler, but said it could only be utilized if running primary/secondary. Not sure exactly why though.So at this time I am still not sure which way to go. I will take a look at the Nimbus control tonight though. It would be nice to be able to buy a conventional pump instead of a dc pump because when it fails, it would be cheaper to replace.
Rick

rick in Alaska

So I just checked out the NImbus control and noticed it says it can only run psc motors, so the ecm pump won't work with this application. Also, it says there is a $400 minimum order. So, is there somewhere to buy them in single quantity?
Rick

SWEI

Correct -- it will not control an ECM. Be aware that you probably won't achieve anywhere near 10:1 turndown, so buy the Taco VVF if you need that. I view it as a stopgap measure until we have small ECM circs with 0-10V control inputs.

They will sell you a sample order (once) of any quantity. After that, the $400 minimum kicks in on the Nimbus (their least expensive product.) The J-box model is well worth the additional cost unless you are wiring multiples into a control panel. Oh, and pay attention to the minimum amp spec. Bigger is not better.

rick in Alaska

Thanks! I'll look in to this a little more.
Rick

Tinman

From what I understand, not all PSC motors are speed controllable either?

SWEI

Most fans and centrifugal pumps.

hot_rod

Does the Nimbus have more "electronics" onboard than a common Triac "wave chopper" relay?

We have sold a bunch of these, which wire to our solar controllers, 120V output to run circ pumps over 1 A.

I hooked a 5 HP shop vac to one and it modulated fine, but got smoking hot without the heat dissipation block.

When they rev PSC motors down to the low end, the motors will pulse quite a bit. We have had complaints of the piping vibrating under these conditions. SolarFlex runs thru the attic or dropped down a stud space without any fasteners or suppport can be a problem.

SWEI

hot rod said:

Does the Nimbus have more "electronics" onboard than a common Triac "wave chopper" relay?

On the power side, no -- hence my warning about the limited turndown ratio. On the control side, definitely.

We have sold a bunch of these, which wire to our solar controllers, 120V output to run circ pumps over 1 A.

I hooked a 5 HP shop vac to one and it modulated fine, but got smoking hot without the heat dissipation block.

Look at the spec sheet. They offer a range of sizes with clear engineering guidance as to what amperage ranges are supported. The minimum and maximum ratings are both real. Minimums are required or they won't work. Maximums represent continuous ratings for inductive loads -- startup inrush is already factored in.