Triangle Solo

CMadatMe

Ok..Have a job where the customer is requesting a TT Solo 175. It's 5 zones with DHW via a Smart 60. After reading post after post about not having to pri/sec or use a LLH with the boiler I have a question. Please correct me if I am wrong.



According to the manual the minimum allowable flow rate at full input for a PS175 is 8gpm. So if only zone 1 and 2 are calling on my design day and the system flow rate is only 5gpm I take it I then have to pri/sec or use a LLH? Please correct me if I am wrong.



I was curious to the PS110 based on the post I see and it's min allowable flow rate at full input is 5gpm. If the above is true then how come I hear so much about not having to pri/sec the boiler? I don't know if I have ever seen all zones open and close at the same time and would think that less than this flow rate would be seen quite a bit.

Thanks in advance.

Gordan

Wouldn't it modulate down if only a few zones are calling?

In other words, it shouldn't be at full input but at partial input. So, you may want to look at flow requirements at minimal input, and make sure that your system flow is above that.

CMadatMe

How Does The Boiler Know

How many zones are calling? How does the boiler know how many btu's a particular zone would need or the combination of 2 zones? It only knows that I need x water temp @ design day and works from there. It also only knows the delta-t across itself.



After speaking with tech. My original thoughts are correct. If my system side flow rate of any zone is less than the min flow rate at high fire I must pri/sec or LLH.



 

Jean-David Beyer

How does the boiler know how many btu's a particular zone would need or the combination of 2 zones?

I do not know for sure what my boiler does, but it could make educated guesses. It knows the supply temperature to the house and the return temperature from the house, so it could know the heat loss of the zone(s) being used. I do not know if it uses the return temperature to influence the firing rate though. It will shut down if the supply temperature gets too high. I imagine if most of my zones shut off, and the firing rate remained the same, the supply temperature would go up. Since it is a mod|con, I assume it would reduce the firing rate to keep the supply temperature to what the reset curve asks for -- if it can. But my upstairs zone requires so little heat that the boiler cannot modulate that low. So it goes into on-off mode unless it is extremely cold outside.



On the other hand, I would not wish to rely on this mechanism to keep enough flow through the boiler's heat exchanger because even if the average temperature out of the boiler was what the reset curve was asking for, with only that low-load zone running, the instantaneous temperature inside the heat exchanger might well go too high even if the average was correct.



Why the aversion to primary|secondary piping (or, equivalently, using a low loss header)? Just the energy to run the primary circulator?

eluv8

The answer is simple

1) The boiler does not know.



2) Primary secondary would be required if the flow rate of your smallest zone is lower than LOW FIRE btu output. (If you are using a modulating boiler)



It takes work and most manufactures do not recommend. But, it can work IF, things are calculated properly.



I have done it several times for the right application.



I will ask a question, Why would you want a 175,000 btu boiler on a system that is designed for 5 gpm? That is a wicked Delta T at design of around 60 degrees, not figuring shoulder seasons. (It would be deeper in the condensing range at the sacrifice of comfort and or heat emitter sizing)



Which brings to mind another question. Does Triangle Tube have a max Delta T across their heat exchanger.



The minimum flow rates are simply the minimum flow that will maintain an acceptable delta T across the heat exchanger during full fire. The required minimum flow rate decreases as burner firing rate decreases. If the flow rate is not decreased then the delta T will decrease across the heat exchanger.

CMadatMe

Great Question

Domestic. This is a 4 apartment house. The heat loss is small per apartment but their is an exisiting Smart 60 with the possibility of all 4 showers going.  Indirect is only a couple of years old. Would have gone with a smaller mod/con if I had an existing 80 gallon tank or was replacing the indirect.



You right on the low fire as an adder to high fire. Triangles manual clearly states high fire. On the other hand Viessmann gives both low and high. I asked the question to clarify the constant posts I see here about not having to pri/sec this particular mfg boiler. All over the manual it states in bold pri/sec is highly recommended.

Personally I like low loss headers instead. Cleaner, easier, better protection of the heat exchanger, no temp drop across zones as multiple call and I have better control over my system side flow rates by using ecm style system pumps.

SpeyFitter

Another Indirect

You have a few options - the best one I think if you want to go with a 1 pump system is to go with the smaller TT 110 and add a second indirect and use that to buffer the lower recovery of the boiler. But this may not be the cheapest -

Certainly the 175 can hammer on that existing tank and have it pushing some serious recovery rates but this will also hurt them short cycling during the shoulder seasons AND definately require primary secondary or a LLH system.

The other option is to go with the TT 110 and keep the 60 gallon tank and take a chance while keeping the owner in the loop with an open mind as to taking this risk. You could set the tank to 140 degrees temperature (which will shorten it's life span a bit but it's still stainless right?) and mix it down to 115-120 degrees for the lines with a tempering valve to help it's capacity. This way, IF they have problems with running out of hot water, how much work is it to add a second indirect which would be similar to the first option anyways?  (and you could provide provisions for this option in your installation).

CMadatMe

Thought About That Too

If the Smart Manual gave more ratings at given water temps and input btu's instead of the 200 degree boiler temp rating on a 90 degree rise it would be nice. What I would like to know is what will a Smart 60 give me for 1st hr recovery with 110,000 btu's of boiler at at 70 degree rise with 160 degree water. Same for 180 degree water.  The problem with indirects is there is no standard for rating so how the heck would you figure it.

eluv8

Thats be the problem

Not the first time that's happened!



I see it with these crazy master showers that dump 10 - 15 gpm on their own and have 3" or 4" drains. I have to laugh when the owner then says they want a "GREEN" house and they have no intention of ever planting a garden.



Bottom line: If Triangle says no low fire designing then that makes things pretty cut and dry. I would not want to jeopardize my warranty or put my name on something not supported by the manufacture. They may know something about the design of their boiler that they are not telling the public. Time will tell, the low pressure drop and advertising seems to encourage the design.



Knowing more about the project I would consider two options. In order of preference.



1) Two boilers, 1 tank = High DHW recovery, 8-1 turndown on two Triangle Tubes, and Redundancy (They all need serviced).



2) One boiler, 1 tank + 1 heat loss accounting for some shoulder season. Calculate how often the boiler will cycle per hour at low fire. If its over 4 times an hour I highly recommend a buffer tank instead of the closely spaced T's or even the LLH.



3) Do what your competition would do and JUST PUT THE DANG THING IN and hope it works past your warranty and even better 3-5 years. The customer will be happy by then with all the money they save from the low return water. Triangle Tube makes a good boiler you will be fine, just pick up an extra igniter and keep it next to the boiler.

eluv8

Smart 60 Recovery

If someone does not chime in I will run some calculations for you. Unfortunately I can not find my file from when I was comparing the Smart Tank to other tanks and their recovery rates. I have not bought or sold Triangle for a while so I have misplaced it.



Unfortunately I am limited on time since I am also looking for work at the moment and trying to get my house ready to list.

SpeyFitter

Fiscal responsibility & Boiler longetivity

I won't mention any numbers as pricing talk is a no-no on here, but let me tell you that after some quick price checking right now, the 2 options below are quite close - pretty much negligeable...the way I see it which pretty much points you exactly where you need to go...

1)  Triangle Tube 110 Boiler pumped directly through the boiler into the radiant for heating (1 ECM Pump - no pri/sec or LLH) and added an additional Smart 60 so the boiler would be heating 2 Smart 60 indirects to buffer the lower recovery rate from the boiler

versus

2) (1) Triangle Tube 175 Boiler pumped with a LLH or Pri/sec pumping for heating and also heating the existing single Smart 60 indirect.



The key difference however is that the 110 will not be short cycling as much as the 175 with the heat loss, and if you pipe the (2) smart 60's in parallel with proper isolation valves there will be redundancy in the tanks since one is older than the other if/when the older tank goes before the newer one. Also, you can lower the tank temperature of the indirects since you'll have more overall capacity which might help push the smaller boiler closer towards the condensing zone, and will also help the tanks and the building piping last longer.



I think you shoudl go with my original suggestion - suggest a 110 with the original single Smart 60. Bump the tank temp up to 140 and mix it down to 115-120 so you have additional recovery. Allow/provide provisions so that if there isn't enough hot water with this set up, you can easily add an additional second smart 60 down the line.  This will reduce costs for the owner significantly (potentially), and reduce short cycling on the boiler, which ultimately leads to better efficiency of the system, plus he'll have one less pump pulling power assuming you can do a single ECM pump for the radiant.

CMadatMe

Thanks

That would be very helpful.

Gordan

It doesn't know how many zones are calling...

...and it doesn't know the flow, but it does know the supply temp rise rate at given input. That's fundamental to its modulation logic.

There could be something peculiar to the MCBA (or the way it's implemented in the TT) that would interpret a somewhat rapid rise rate as restricted flow, and trigger a lockout but, if I recall correctly, the TT manual says that the burner control starts low and modulates up on a heat call, not the other way around. So, if it is able to maintain the desired supply temp at lower modulation (and it would be, due to lower flow through the boiler) it would never modulate up. Never had my hands on one so I'll defer to others.

Jean-David Beyer

I think there is a more fundamental issue.

A lot of this discussion seems related to circulating enough water through the heat exchanger so the heat exchanger is not damaged. And clearly, in the long run averaged over the entire heat exchanger area, this must be done, either by controlling the flow rate through the heat exchanger, the temperature of the incoming water, or the energy input.



But another reason for wanting a high flow through the heat exchanger is because of localized effects, and these may require even more rapid flow than that decribed in the preceeding paragraph.



My heat exchanger is an aluminum casting with water on one side, and fire on the other. Now on the fire side there are pins something like those in a conventional cast iron boiler (though they seem to be smaller). At the top, where the gas and air are burned, there are few, if any pins, and they are short. As one goes down the heat exchanger these pins get longer. Now these pins need to be cooled or they would melt. And the way they are cooled is that they conduct the heat to where they are attached. And on the other side is the water. I imagine that by the time you get to the water side, there are spots that are hotter than others. These spots are where the pins are. And you must cool those spots enough to prevent melting. It is not enough that , overall, the heat exchanger is cooled enough; the hottest parts of the heat exchanger needs to be cooled enough and, depending on its design, this may require more water flow, perhaps even turbulant flow, to cool even those hot spots.

Gordan

I'd imagine that thermal stresses would be of greater concern than melting

But, otherwise, yes, I'm sure that you could push things to the point that they break. Is that likely to happen before either the flue gas temperature or the supply temperature rise trigger a lockout? Perhaps. I think it's pretty safe to say that flow requirements at minimal input are lower than flow requirements at maximal input. By how much, well, that's the manufacturer's prerogative to provide, and if they don't, you're best off either a) designing for whatever flow requirements they do provide, if only to preserve your warranty, or b) choosing another boiler. So we've come full circle. :-)

bob eck

solo boiler

just a thought on the domestic hot water demand you said there are 4 apartments what are the shower head GPM? are they still 2.5 GPM? If so look at replacing them with ALSONS 1.6 GPM shower heads. THis would lower your water and sewer bill plus if using less hot water you will use less energy to make domestic hot water. I have ALSONS 1.6 GPM shower heads in my showers and everyone likes them. If you can not get them where you live email me I work for a P&H wholesaler and I will get you a price and we can ship them to you.

You can call triangle tube direct with questions on their boilers.

CMadatMe

Bob Eck

Thank you for the post. I manage a plumbing and heating wholesale company. I'm  well aware of the heads. Even using 1.6 heads that give me a need of 6.4gpm which is pushing a TT60 at 110k btu's. If it was a single residence probably would try it but tenants when not paying the utility tend not to be energy conservative.  Would rather not push the envelope and have call backs for my contractor.



 Triangle was kind enough to get me the info I needed for the indirect and provided me with some nice insight into what the Presitge does on intial fire. Be very careful promoting the need not to pri/sec their boiler. While you can get away with it in some applications, you need to finish it with some flow rate mins and what's left in pump head once you get across the boiler aalong with the need to turn off freeze protection when handing out the advice. Not bashing you just passing along some info.

Unknown

Respectfully disagree,,,

are you sizing the boiler based-on domestic needs alone?

I have done many in 4-5 unit apts. , never a problem with priority(provided the tank is large enough for all unit needs), I fail to see how oversizing will do anyone any good.



Typical "relying on the wholesaler" sizing technics,,, no-one wants to admit they`re mistaken,, and no-one wants to take a chance on themselves.

Been that way for years, in my area anyway.



I very seldom use P/S piping on these units.

CMadatMe

Dave

That's why I wanted to find out the ratings of the Smart 60 at 100K btu's. Heat Loss is in the 80k range. With 4 showers the 60 would only store enough water for 10 minute showers (which to me is a long shower) and the recovery is key. The 60 already exists on a 200,000 gas guzzler and is only 2 years old. Personally, I would do an 80 gal and the small boiler. Gives me enough at dump with a cushion.





This is a portion of the e-mail that I recevied from Triangle on the Prestige.

The Prestige will light off and HOLD at 50% firing rate for one minute, to allow the system (water) to stabilize.  From there, the boiler knows where to efficiently begin modulation, instead of hunting around in the early stages of firing.  For that reason, a Solo 175 will hold at 85K BTUs for a minute before modulating .  If the flow rate at that time is less than 4.25GPM (40 degree delta), short cycling MAY occur.



Carry that math to the 250 and 399 and you can see where small loads can catch you



So on a PS110 for instance 50% of the firing rate would be 50,000 btu's or so. How many zones do you know that carry 50? On a PS60 that would be 30 don't have that many either. So now you can see where pri/sec or a LLH would help.



Always a pleasure to jab.



Just received the ratings manual. At a boiler output of 100k with 180 degree water temp on a 70 degree rise I get basically 2.8gpm on 100K. What do you think? Manual is attached.

Unknown

Still losing me,,,,

I would think the primary use of any mod/con would be heating.

The secondary issue is the domestic HW,, which most have priority for,, on TT the priority "time-out" can be altered regardless of the indirect size,, so I fail to pinpoint your design problem.

CMadatMe

Not My Issue

I want to go with a 100K boiler and be done with it. Now that I have the ratings for the Smart 60 that's the way I'm going. The problem with indirects is there is no standard on performace. Everyone has their own ratings so getting this manual  was the key. So we quote a Viessmann Vitodens 100 (less than a PS110) as an option and go for it..

Unknown

Well,,,

to each their-own!

If you (as a wholesaler) live in a community that can sell Veissmann) then,, all the more power to you.



Me particularly thinks you are a curious wholesaler who cares nothing about the install, only making "big bucks" by oversizing with the intention of "not being wrong & collecting the money",



Have you attended any of these training courses the various companies offer??

bob eck

solo boiler

Triangle Tube prestige solo boilers when there is a call for domestic hot water the boiler delivers 180*F water to the indirect. Is the boiler on high fire for all domestic hot water calls? if you run out of hot water install a 80 gallon electric water heater and circulator with the smart 60 you already have installed. Install the ALSONS 1.6 GPM shower heads they will never know that the flow is reduced trust me. call your alsons rep and get a sample and put one in your house. what is the wholesaler you work for? and whit city?

CMadatMe

Come On Dave

Never oversize..That's why I wanted those ratings....It's not about $$ to me it's about doing the right thing for my customer. I could care less which boiler he chooses but when I quote jobs I always give options and the information he needs to make the decision. It's then up to him to choose what he wants.



As for training, I host an evening class every month on high eff products and equipment and not a sales class, technical done by that particular products training guy or rep. The plan for July, I am hosting a dinner where everyone will bring their labtops and take the new courses on the Fujitsu new multi zone units. You have to take the course in order to purch these units. Courses are suppose to be up on their Dealer Portal soon....Wanna come. Always a pleasure...

bob eck

triangle tube solo

what about using the PS110 and smart 60 and storing the water in the smart 60 at 160*F and installing a good temp valve to take the water temp down to 125*F going to all the showers. Would your domestic hot water last longer that way?

CMadatMe

That's the Plan

After getting that manual and being able to see the recovery of the Smart 60 at 100,000 btu's that's the plan. Customer decided to go with a Vitodens 100 WB1B10-35 though.