Specifics on Wilo Stratos + TT Solo 60 + SMART 60

Craig Benson_2

First off, thanks for all the help so far.

Getting closer to specific components and final system design. Some specs:

Total load = 36k btu/hr

Total Radiant load = 32k btu/hr = <4k>?

10 degree Delta T = 7.4gpm @ 10.8ft

Warmboard zones above crawl = 124* water temp

Warmboard zones above basement = 115*, 125*

Basement 6" slab = 79*


From Triangle Tube literature, minimum flow through boiler must be 3gpm. Head loss at full system flow of 7.8gpm looks to be around 5.5ft. Wilo Stratos 16F variable head 4-16 ft and flows from 0-14gpm. Triangle Tube factory literature provides schematic for single pump installation (Fig. 11, pg. 22).

Where I need help -

How do I temper the slab supply temp w/o adding additional circ?

How do I add indirect tank and give it priority and full-fire capability while utilizing the single Wilo circ?

What about a single zone call? My zones are too small to provide required 3gpm individually.

I would like to go with the single Wilo because of the simplicity it offers and the ability to match flows more precisely with my relatively small system demands.

However, I can buy 4 Grundfos 15-58s for the price of 1 Wilo and the piping is textbook P/S but the zones will drastically overpump even on the lowest speed setting.

If I decide to go with loop actuators in the baths/beds based on a year's heating experience, the overpumping potential is greatly magnified.

Should I just install an "old-fashioned" system and get on with my life? Wait a few years for the technology to advance some more? What about future integration of a solar collector array?

Thanks again.

Craig

Mark Custis

I love the kiss

of your idea.

The mod/con we use, DEMANDS P/S piping, so I would need to go look at fig. 11, pg.22.

I was right there with you until you tossed in the indirect, the manual three-way we use wants to be pumped away from. I could still see it working so now you are in a multiple temp opperation, so now I am not so sure one pump will be enough. The added tees for future solar locked the door on the one pump.

Here is what I would do since the long range benefits of an ECM pump are far greater than the up front costs. I would go P/S with "JUST" enough pump to handle the boilers needs. Then add the stratos for the rest of the system. I have used them and it is very difficult for me to spec a PSC motor driven pump. The ECM will give you the lowest "wire to water" cost and handle the actuators, and when it is time to account for the solar just push the button and change the curve.

Craig Benson_2

Thanks Mark -

What about the indirect? I assume it is best served with a circ and supply off the system supply before the primary circulator to isolate the 180* water from the rest of the system.

So now I have a standard primary/secondary setup with the priority signal running a solo circ for the indirect and shutting off the primary circ and Wilo secondary.

Which type or brand of tempering valve works with the single Wilo circ? Slab calls for 79* water 2.5gpm @ 3.6ft. What is the smallest pump available? Almost gets down to potable hot water recirc flow rates to individually pump this zone. It is the most forgiving zone being concrete though...

Then the only thing that makes sense is injection mixing on the slab, Grundfos 15-42 Miximizer and 15-42VS have the right curves...just a little more $$ than circ + tempering valve...

I envision a system overhaul and solar collector add-on within five years. Maybe I will wait until then to get the "latest and greatest" in variable speed technology...


Thanks for your help, still trying to decide if the Wilo is really worth it or not. Also need to make sure I am looking at the correct model of Wilo Stratos. I have the capability of using 230v as easy as 110v if that matters.

Main question at this point - Are we going to feel and experience tangible benefits of adding $1000 to the system in the way of variable pumps?

Check my math, 1/25hp = 30watts x 4 circs = 120watts for circulator power. For the majority of the year I would not even be running at that level of power usage. Basement has 30 can lights with 65W bulbs for comparison.

Thanks for your help, I think at this point I need to stop thinking and start plumbing...

Mad Dog_2

Paging Mr Wilo...MARK HUNT............................

If you can get a hold of Mark, He'll give you sound advice on Wilo...he's a trainer for them. Mad Dog

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mark Custis

Mad Dog

We get to meet Mark next week in Cleveburg.

clammy

All comes down to boiler sizing really

I need to get a definitive answer on sizing before I can really proceed. If we are talking 110 rather than 60, which has a lot of people offering different opinions as to which size is ideal for this installation, then the possibility of using the Excellence combined unit makes some sense for my application.

From that standpoint, a simple solution as to how to deal with the low temp zone and I am looking at the most streamlined and compact solution.

I want to have the best of the best in utmost simplicity and functionality or the utmost in dependability and tried and true basic principles. I don't really want to complicate things just to have the opportunity to spend more on a fancy pump.

It all boils down to making the right choice on the boiler sizing. If I go with a PS60 then I am most likely looking at by the book primary/secondary. If the 110 will modulate low enough for shoulder season usage and the de-rating for altitude and propane fuel source help get down to a true 25,000btu/hr minimum output then the Excellence and a Wilo with some piping gimmicks or tempering valve and factory 15-58 and I am set.

Thanks everyone for your patience with this hayseed farmer. Pretty soon it will be summertime and I'll be wondering why I spent so much time and money on radiant heat and none on air conditioning...

Craig Benson_2

Progress!!

Good conversation with Mark Hunt this morning. We talked at length about the plan to use the Wilo ECO16SX with the Triangle Tube Solo 110 and pump through the HX with the single Wilo. Indirect will use the existing 15-58 with some re-wiring at the control panel.

Idea is to let the basement 6" slab have higher temp water and let the Wirsbo modulating T-stat do it's job to regulate the slab. Then I have a simple system that should perform EXACTLY as spec'd - pretty cool to just watch the thermometers on the loops and dial in the pressure. Looking forward to this project for the first time in months!

Now I'm just looking for pricing and availability on the boiler and circ, should get an order out by tomorrow and start the install next week.

Guy Woolard was also a ton of help and I'll probably have a ton of follow up questions once we get going on install prior to start-up.

Thanks everyone for your help and pointing me in the right direction.

Uni R_2

Why the 110?

So you will wire the internal 15-58 to the DHW, and then pipe the Wilo ECO to where the DHW normally connects?

Please note that the internal 15-58 does not have a flow-check so you will need one in your DHW loop.

Why not go with the 60 instead? Then you wouldn't need to be crossing over the wiring, which could really confuse someone else servicing your Prestige late, both pumps could be obtained with IFCs, the pumps and flanges would be outside of the enclosure (who wants to open it up to change speeds?) and the minimum modulation will be under 20 MBH instead of barely under 40 MBH (several of us have clocked 110s and they all seem to have a minimum modulation of about 38 MBH at normal altitudes).

The modulating T-stat sounds interesting.

Craig Benson_2

Why 110 -

Good question. What is the definitive net output rating for a propane fueled boiler at 6000' elevation. I know I am borderline between the units and I still flip-flop based on this because I have not heard anyone say definitively what a "real-world" output is. Can you provide that info?

In all reality, the domestic hot water needs in my house are probably much greater than the CH demands.

Why would we need to switch the 15-58 speed once it is installed - it's only handling the SMART indirect.

With the Wilo outside then it is easy to adjust pressure based on loop therm. delta Ts and a little fine tuning on balance valves - could get really fancy and install loop therms on the returns if you really wanted to see what was happening.

A simple note on the inside of panel would explain the wiring, I will most likely be around if anyone opens it up for service.

Still haven't purchased the boiler, anyone with personal experience at 6000' with a PS60 please feel free to chime in. I have been recommended a 110 by a professional hydronics designer who has one in his own home at 5500'. Everyone else just designs ski chalets and puts in twice the capacity needed.

Unknown

I believe it's approximately a 2% drop per 1000' of elevation for gas boilers.

Mad Dog_2

First time???????? boy are you in for an epiphany my boy

Mad Dog

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

scott markle_2

Save the solar for supplemental DHW where you will see a meaningful pay back.
Supplemental solar would also compensate for fact that the solo 60 is a bit deficient for "endless shower" dhw performance.

I put a flow meter on the primary loop of a solo 60 and I'm measuring about 5.5 gpm through the low loss header and 1'' pipe work. With a Wilo star 5. Pretty much exactly what the pump curves predicted.

One thing you can be sure of if your only moving 3 gpm and your supply target is under 95, you will short cycle. Because the boiler lights at a mid level modulation it will reach these low targets temperatures very quickly. If you anticipate low temperature low load low flow conditions be prepared for 90 second burn cycles. The boiler does have a time out feature that will suppress the next burn, it's maximum setting is 5 min. It's entirely possible that you will see 90sec. on 600 sec. off for operation.

I think multi zone low mass boiler cycling is a bigger problem than many people realize.

BTW- when I proof read after I post and then edit the mistakes, does an Email get sent for every correction?

Unknown

the 110 can fire for 90 seconds with no load at all on a 20 degree differential.

the 60, must be about double that? on at 85 off at 105 for a 95 average.. right?

3 GPM even at a 10 degree dt is almost the minmod on the 60... Is 3 GPM really important there?

scott markle_2

Rob, I can not find a parameter for CH differential in the prestige literature , I assume it's variable and automatic.

I have been watching a Tekmar 420 solo 60 combination and I'm seeing about 90 sec to exceed a 95 deg target and shut down. Low loss header and small secondary load. Is the water volume the same between the 60 and the 110?

Unknown

There is always a variable scott take your 420 off of auto-differential. I think both boilers have 2.5 gallons internal.

scott markle_2

I don't get the variable joke?

I have switched to a fixed differential it helps. Still find the 420 overeager to reach target and setting targets that are inconsistent with the odr curve, ie hotter than necessary.

Unknown

not really a joke, but last i knew the docs on the MCBA were a bit obtuse for sure.

the 420 will split the differential around the actual target, and if it's trying to heat up (rather than maintain) it will often shoot for max design temp (design plus ten) to respond as aggressively as possible. maybe that's what's up?