Replacement for 1960's era N.G. boiler....

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NY_Rob

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After reading the Lochinvar KHN Installation & Operation manual- it looks like the KHN has the features I'm looking for:
7-day programmable night setback for space heating. Setpoint minus 0-90deg range.
7-day programmable night setback for DHW. Setpoint minus 0-90deg range.
Boost feature (up to setpoint +25deg) for higher firing rate under pre-determined conditions.

With that in mind, I could leave my t-stats at a constant temp 24/7, then program the boiler's control a few deg setback at night for sleeping comfort, program in the night setback stop time and let the boiler do the math to keep us warm.


Can someone explain the role of the "included Grundfos UPS15-58F boiler circulating pump" vs. the also required"system circulator pump"?

Thanks.....

Single Boiler - Single Temperature with Zone Valves - DHW Priority.jpg
 

Dana

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That's the "primary" loop pump, vs. the pump driving the radiation loop AKA "secondary" loop. The purpose is to guarantee that the minimum flow through the boiler is met, independent of the pumping rate & delta-T is designed for the radiation. While in fact many/most residential systems would work just fine (or even better) as a single pump system, Lochinvar is fairly adamant about their boiler's being installed only in a primary/secondary configuration, even if you do the math and prove to them that it's not a problem. That ends up using a lot more electricity (especially with a dumb 3- speed like the UPS15-58F rather than an ECM drive smart pump.)

By contrast, HTP's UFT series is specifically designed to be pumped direct in all but the most exotic of system configurations.
 

NY_Rob

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Bear in mind, 120F output in Slantfin's documentation is average water temp (AWT), not boiler output temp..
Thanks Dana,
If you look at the diagram above- would that be closest to the reading taken from the "system supply sensor" vs. getting the reading from the return sensor at the boiler? The boiler can get it's water temp readings from three different sources according to the manual.
 

NY_Rob

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That's the "primary" loop pump, vs. the pump driving the radiation loop AKA "secondary" loop.... That ends up using a lot more electricity (especially with a dumb 3- speed like the UPS15-58F rather than an ECM drive smart pump.)
By contrast, HTP's UFT series is specifically designed to be pumped direct in all but the most exotic of system configurations.
I like the idea of simpler vs. more complex with more moving parts.
Once I get my quotation from the local contractor on the Lochinvar, I'll ask him about the HPT UTF series, in speaking with him the other day- I got the impression he can get pretty much any brand out there.
 

Leon82

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I think there are different situations to use either sensor. I use the system sensor but if you unplug it the boiler uses outlet sensor.
 

NY_Rob

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Thanks Leon,
The manual states that "outlet sensor" is default until "system sensor" is installed.
Since the package includes the "system sensor" I guess they think it's important.
 

NY_Rob

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Just took a look at the HTP UFT series install diagram, Dana's right... very straightforward!
A lot to like about the UFT series!
Hopefully I can get a quotation for one....

HTP UDF.jpg
 
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NY_Rob

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Any other mod/cons with a low fire rate that employ direct piping vs. P/S piping?
I sent an inquiry to supplyhouse.com- they don't carry the HTP brand.
Sent in inquiry to HTP this morning regarding local dealers, etc... they didn't respond.


Edit... changed HTC to the correct HTP brand... thanks Dana.
 
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Dana

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It's HTP (not HTC), and the series is UTF (not UFT), just in case that's causing any confusion.

Many/most mod-cons can be pumped direct for simple residential applications, but it requires doing the math so that it's neither over or under pumped. With a smart pump it can be optimized within a range, but it takes a true hydronic designer to spec it all out. (Some mod-con installers are up to it, others not so much.)
 

NY_Rob

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Thanks Dana,
Most likely if the factory specifies P/S then that's what the installer is going to go with if nothing else under the pretenses of "warranty coverage".
Maybe I'm putting too much importance on the ability of being able to pipe direct?
 

Dana

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It's more likely the case that the manufacturers are ascribing more benefits to P/S configurations than actually exist.

Another low-modulating boiler that could work here is the Navien NHB-55 & NHB-80. Predictably, the installation manual specifies using their pre-fabricated primary /secondary manifolds as the gold-standard way to install them (with the exception of their air-handler system example.
 

NY_Rob

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Since I haven't gotten anything response from HTP yet, I did a little research..
Looks like HTP makes their UFT series as a rebadged Westinghouse product:
http://blog.htproducts.com/westinghousewaterheating/introducing-the-universal-fire-tube-boiler

This sure looks like the HTP UFT-80W....
https://www.libertywholesalesupply....hly-efficient-universal-fire-tube-boiler.html
and..
http://www.thewholesalewarehouse.ne...-highly-efficient-universal-fire-tube-boiler/

Looks like I can order one directly at almost half the price of the Lochinvar and use direct vs. P/S plumbing..
 

Dana

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Well, I'll be...

You're absolutely right! Compare the photos of the innards on p.2 of these documents:

http://www.htproducts.com/literature/UFT-brochure.pdf

https://www.libertywholesalesupply.com/product-doc/westinghouse/WBRU_Brochure.pdf

FWIW: This boiler has been on the top of my current list for what would replace my current burner, should it crap out any time soon.

It's unlikely that Westinghouse designed it with HTP being the re-badge. The converse is more likely, or even yet another manufacturer selling into multiple channels.
 

Leon82

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It says 3/4 gas inlet size. I wonder if you need a 3/4 pipe or if you can reduce it to half inch.

You may need to rework some of your gas line.
 

Reach4

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Since I haven't gotten anything response from HTP yet, I did a little research..
Looks like HTP makes their UFT series as a rebadged Westinghouse product:
The Westinghouse Premium High Efficiency Gas Water Heater is a rebranded HTP Pheonix Light Duty water heater. So maybe a little cross-branding can go the other way.
 

NY_Rob

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^ sorry about the confusion regarding rebranding/rebadging...
It certainly seems like HTP makes the boiler, then they rebadge it for Westinghouse.

At any rate, I'm very happy as it seems like a really good fit for my needs, at a very reasonable price.

After looking at the docs for the HTP UFT-80W/Westinghouse WBRUNG080W it seems the only thing it doesn't have is space heating and DHW tank nighttime setback. It does have Boost, so if I go with a moderate setback (maybe -3 to -4deg at night) that should still work out.


Thanks for the heads-up regarding the gas supply pipe sizing Leon.
A .75" supply pipe does seem large for a 10' run to a 80k max input boiler, maybe they just sized it for the largest boiler in their UFT line (199k BTU/HR)? Going from .5" to .75" isn't a deal-breaker for me as my gas supply will have to be reconfigured anyway since I currently have a gas fired DHW heater plus my boiler and will be going to a single boiler with an indirect DHW tank.
 

Dana

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You need a lot bigger pipe than 3/4" to feed a 199K burner, and if it's a long run with the "equivalent length" ells & tees even 3/4" might be pushing your luck with the 80K burner. Most would be fine with 3/4", but dropping it to 1/2" isn't a great idea. To avoid problems with modulating burners you want a home-run to the regulator, not running of a branch with other appliances, and plenty of margin on the gas supply. With half-inch line it would have to be VERY close to the regulator. (The units are 1000s of BTUs/hr.)

Natural_Piping_Chart.png
 

NY_Rob

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Thanks Dana,
Going by memory, my gas supply run to the the boiler is a bit under 10' total (horizontal + vertical) with two elbows from where the 1" or 1.25" ? pipe from the outdoor meter/regulator enters the basement.
I'll look at it in detail tonight to get the exact routing, length, etc...

Thanks again......


EDIT.... at home now- took a look at my existing gas supply pipes:
Straight off the 1" main supply pipe- it's a straight run of 3/4" black pipe with two elbows and a T over the boiler then straight down to the drip-leg then a 3" piece of 1/2" pipe off the drip-leg into the gas valve.
Total length of the 3/4" pipe from the 1" supply pipe to the boiler is a bit less than 9'.
 
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NY_Rob

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Being that the HTP/Westinghouse UFT doesn't have any sort of zone control built in (it just has one simple T/T terminal set) is this how I would wire my two honeywell zone valves and t-stats?
tstat_wiring.jpg


Any benefit in using a zone controller vs. the simple setup above?
 
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NY_Rob

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In looking over circulator pumps, for the CH/System pump it seems like a variable speed circulator like the Taco "Viridian Delta-T Variable Speed ECM High Efficiency Circulator" might be a good choice to use with the HTP/Westinghouuse UFT boiler.
I have one long 170' zone and another zone consisting of two shorter (maybe 100' each) loops tied together in parallel.
Setting the variable speed circulator in "Delta-T" mode should help keep the flow rate optimized even with this unbalanced arrangement?
 
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