are there really 10-1 mod cons

keyote

And if so and you had an indirect smart 50 wanting i think 140 kbtu, but a radiant ch load of 52kbtu [with possibility of an addition making it maybe as much as 65 kbtu]- but the problem being small zones in a 5000 sf 3 family, [if i combine zone id rather not] being only 8000 kbtu smallest load, would you say something about 80kbtu with 10-1 be about right?
Right now im trying to make a used TT110 i already have work, but the cost of buffer tank and odr mixing valve etc to make it work while cheaper than a new boiler may be an inefficient fix for what was to be an efficient system. and perhaps reselling the used stuff and saving the buffer costs is worth considering now rather than later as planned,

I suppose the other option is foregoing the buffer and just letting it short cycle like crazy until im flush

It seems some say buffers are always a help and others say they are always a fix for poor design , granted we are fixing an oversized boiler i bought used before i got an accurate heat calc, but we are also dealing with a large house that ought to be zoned much smaller than anything other than the mythical 10-1 modcon could do.At least i would like that level of control because occupancy is erratic, there are tenants, and i would have thought it could save energy.

I wonder because i dont have practical experience whether this is a real or theoretical problem, is the size of the smallest zone really the way to predict the smallest real life call, what are the odds of only one small zone only needing heat. What do all the zone need when its 65 degrees out?

I know some of you mentioned 10-1 mod cons i cant find them except in commercial sized

Paul S_3

lochnivar KHN has a 10:1 turndown

Rich_49

Mass is always good ! It can be leveraged . The most efficient boiler or source is one that is not operating , only mass can offer that opportunity when loads or zones are smaller than minimum fire .

How exactly are you zoning this house ?

The zoning argument is mostly based on the the idea that the equipment should be on and at a firing rate that equals the load at a given time . Sometimes comfort is hard to achieve in all areas and compromises are made . Every building has it's own needs but the needs of the occupants are more important . So , I'll ask the question .

How come we as industry professionals who have accepted a role to provide heat / cool / comfort have not come to grips with the fact that zoning is not a bad thing ? The car manufacturers have addressed it in the form of many vehicles that have many comfort zones based on the individual occupying a certain space in that vehicle .

When you zone for that situation you also can afford yourself the option of not mixing down so much . When a floor surface temp reaches x* in a zoned system the T stat will satisfy , flow will cease and the floor will not overheat . One just has to pay attention and take the necessary precautions during design . See the PDF

I am not alone in this theory apparently :
http://www.healthyheating.com/Thermal_Comfort_Working_Copy/comfort.htm#.V6DH4qJQc_g

hot_rod

Questions that none of us can answer. The loads of your building, the weather, occupant use all determine the run times and cycling of the boiler. Those conditions change constantly, year by year, even minute by minute.

The 110 Triangle you have would be fine in my opinion. It is an excellent boiler.
Adding the buffer will do all the things you mentioned, smooth out cycling, serve as an air, dirt, hydraulic separator, etc.

True, buffers do get applied to help solve problem jobs.
Boilers used to come with buffers built in, back in the day, 300 lbs of cast iron and 30 gallons of water!

As for the indirect, it will function with whatever BTU that you supply, it doesn't have a set requirement. Performance numbers are based on a manufacturers defined set of parameters.

Typical 40- 50 gallon gas fired DHW tanks that millions of families have are typically around 40,000 BTU input, maybe 80% efficiency. So your TT 110 has the ability to give you plenty of DHW power, almost 3 times the typical DHW tank mentioned.

You could pipe it with 3/4 tube, flow 3 gpm and still out perform most residential gas or electric fired water heaters

If you must have a new boiler Lochinvar, HTP, Laars and others offer 10-1. I like all the features on the Lochinvar, especially the control. It has a PWM output if you really want a variable speed boiler circ that works properly.

keyote

Thanks paul supply house has the wrong brochure [KBN 5-1 mod] linked but the khn data sheet The tt110 was the favorite boiler on this site only a couple years ago what is this brand like?

Hey Rich I agree people want and will eventually get micro zones and money will be made giving it to them good and hot.

How am I zoning? well that seems to be more a question of what would be possible.I was led by sales brochures to think for 35 bucks a loop i could pop an actuator on every loop and control it all with my iphone lol
since my layout ended up pretty much with each major room with its own loop or at least a bed/bath suite i thought why not, because i have two tenants, because the house has unequal glazing and shadowing, and is four stories,because i sometimes have a large family and some times no family and rattle around alone in a huge house, because i am retiring and may spend months away from home, i liked that idea. id just throw in an actuator and tstat for every loop. since doing it all myself its only material cost. But problems arose the TT110 boiler was too big and had minimum flow requirements and didnt mod as much as it claimed and my heat loss came in much lower than expected. every time i put out one fire another arose as you know having helped.
Just as i was kind of worked out i thought this morning between the cost of the buffer and the mixing valve im halfway to a new boiler that probably wouldnt need them if it really could do a 10-1 turndown.cash is tight now but i thought i better explore this 10-1 before i sweat anymore copper.

Rich_49

Lochinvar KHN , HTP EFT and HTP UFT

NY_Rob

HTP UFT Series with 10:1 turndown:
http://www.htproducts.com/UFT-Boiler.html

Tinman

I just started up 2 KHN199's this morning, my first two. Awesome boilers.

keyote

NY rob that hilarious, i just spent the most useless frustrating 45 minutes chatting with some morons at HTP who even after going through three cust svc reps and calling them stupid morons to their face they still insisted the only 10-1 mods were the 1million and 1.7 million stack units and that the 55 and 80 etc all were 5-1, which because they linked me to old literature i believed.
Im in brooklyn who do you deal with on these? any thoughts on these v the lochinvar KHNs?

keyote

Stephan i liked the look of their literature was imagining a wall hung but why not a floor model i only have the indirect piped i can redo it.

Brewbeer

Install the right sized buffer. I have one (boiler buddy) and it works great. With small zones and low SWTs in the shoulder seasons, you will benefit from having it.

keyote

Hot Rod thanks for chiming in, I dont really really want a new boiler but i was kid of choking on the buffer tank cost, first i couldnt talk myself into using the old smart 30 because the small taps and two tanks and frankly it looks a but limey, so it wa a new buffer then i realized i probably ought to run it hot and mix it down and that outdoor mix valve is pricey in fact the two items are half the cost of a boiler if i can rsell the TT and other stuff maybe its the same price as the lochinvar and simpler and more efficient. maybe.
if the costs are the same is it not more efficient to use a 10-1 modcon that doesnt need a buffer than make a 5-1 boiler work with a buffer.
I do admit what first attracted me was it seemed like a way to not have to run the internal primary and a secondary pump for small heat calls. but im not informed enough to compare pump electric to the buffer standby issue. I read the lochinvar has extremely low flow requirements and pressure drop i wonder if it is low enough i could pump straight through with one ecm to zone valves- hey cant blame a guy for asking? I know im a pest on that issue but it just seems such a no brainer maybe theres a work around no ones mentioned, like a bypass that gives the boiler a bit more flow than the zones are calling for in certain low load situations so you only need one pump. well damnit if there isnt you guys should fix it and make money on it

SWEI

An electric tank water heater can quite easily be turned into a two-pipe buffer.

hot_rod

In these small applications, lets just say under 100,000 boiler range. The challenge seems to be finding a readily available PWM controlled circulator, of the proper size, that can communicate well with the boiler control.

You have read Hatts post about his attempt to use a single pumped V/S boiler and circ combination with an off the shelf circulator.

But there may be some options, I have 3 different small sized PWM circulators on my bench. Next I'll get a boiler, mid mass about 4 gallon capacity, low pressure drop with PWM output and pair them up. I have all sorts of loads to connect, down to a single panel rad zone.

The cravat being all the circs I have are 230V, two from Europe, one is an OEM GEO pump. I have the solar version connected to the PWM output on a Caleffi I-solar control and it ramps up and down just fine. With this controller the pump power needs to go through the controls relay as well as the two wire signal wire. I'm not sure if a boiler with only 120V will drive the 230V pump if it is fed from a separate power source?

Keep in mind, for a manufacturer to step up and build or modify a small PWM Euro pump for the US market (120VAC) takes some commitment. Marketing departments also weighs in to determine if it is a sellable product. Understand that hydronics in general is not a huge market in the US, compared to the automotive and groundwater market potential for example.

Now if you care to move your home project to Europe, you would find a huge assortment of small "controllable" PWM type circulation products, and many other hydronic and solar goodies.

Viessmann has had a boiler available in the US with a VS circ under the hood, consider that option.

keyote

I know i even have a spare smart 30 i could use too but my ocd wont allow me to use those 3/4 taps, but the real problem is and correct me if im wrong as well as a buffer solves several problems a 10-1 modcon does it better. so im afraid i will regret putting the effort and cost into a buffer that if i swap to a 10-1 will be obsolete

Gordy

Now your getting the picture. If in the short term goal is to get a boiler of the right size then all your effort in trying to make something you got a deal on work is for nothing really.


Ceavate all though the 10:1 is nice. You must still keep in mind DHW recovery with an indirect. Pay close attention to their recovery rates coupled to a given btu input.

In many cases the btu requirement for the dwelling load can spec a boiler that is so small that DHW production is less than desirable, or does not meet factory spec expectations.

In your case with a three family. The zoning you want is a little over the top. Which creates extra cost in control, components, and dealing with the low loads of the zones. Zoning should be divided at most into sleeping, and daily active areas. Maybe one for seldom occupied say a basement.

Another curve ball that may get thrown is setbacks. Not good unless the emitters are low mass. In your case I would not call a plate less sandwich with 3/4" hardwood low mass. The monkey on the back is recovery with a proper sized boiler.

You will have no idea of what the tenants may do.

I,will also add zoning, and ODR DO NOT play well together. Unpredictable zoning habits are worse yet.

BobC

An autotransformer might be a very affordable option with small 230v pumps.

Bob

keyote

Hot rod I think with the 10-1 turndown i could go with a 8-80 boiler and still have enough dhw recovery, while i do have 3 baths 2 powder rooms and a kitchen on that tank i dont really think its ever going to see more than two showers simultaneously the tenants i gave each their own tankless rather than run hot water lines up four floors.* kbtu is more than my smallest loop but i can do as you suggest and combine at least until some data logging tells the whole story.
as for the tenants i think the ODR helps its not like a big dumb dragon that just keeps bellowing harder the more windows you open they are going to get cold quick and close the windows. I dont think my zonibg wishes are unreasonable in a 5000 sf house they may not be possible yet but mark my words you will be making a fortune microzoning in a few years. On the big jobs i do hospitals schools office building every room is a zone now chill beams vavs whatever it takes its allways every room a zone to platinum leeds specs. hell its worse than that everything is on Bim and occupancy sensors and iphone apps

hotrod
After i replied to you i checked the HTP and found it only adds about 2 lbs of head through the unit at my flows, and has a low flow requirement I would still be well within the curve of the VT2218, they actually have as one install suggestions of my idea of a diff bypass to maintain boiler flow req.and pumping straight through no secondary.
But now you are saying that the controls in boilers dont work with ecm pumps?! **** ??????how can state of the art boilers not use state of the art pumps?
Why do they even need to do much interacting? The pump decides what speed based on the delta t i give it, the boiler decides what water temp based on the temp i give it and the outdoor reset ratio i give it.
the tstats decide when to call for heat from the temp i give it. the tstat call tells the actuators and zone valve to open. which tells the pump to pump to delta t which tells the boiler to fire to water temp, the boiler adjusts it modulation to keep a water temp for given flow and outside temp.
So what have they **** up this time?

keyote

gordy i sent you a msg earlier was wondering you opinin on the HTP v lochinvar 10-1 modcoms for my situation I guess hotrods comment is going to bear on this vt2218 pump compatibility

Harvey Ramer

Most appropriately zoned systems won't short cycle a Modcon if the boiler control is setup properly. Even a 5:1 turn down. If the boiler control doesn't have the proper control settings, like ramp delay, ect... Then a Tekmar control can be used to modulate the boiler. The Tekmar has zone synchronization which is meant to enhance boiler operation by getting all the zones on the same schedule.

If you have micro zones, a buffer is a good idea.

Gordy

Did not get that.

Harvey Ramer

Which part?

keyote

Harvey the TT110 which i was trying to make work was 5-1 low end 30 kbtu, that equalled two floors of a four story house no offence but i think im entitled to more control than that without having to find work arounds.It worked out that every major room ended up with its own loop and i saw that $35 could screw on and voila a zone so i said **** yeah then i find mod con doesnt really mean what they imply it does. being stubborn i drive all you nice fellas crazy helping me get my way. And just as we get it solved i decide it defeats the whole efficiency thing that the radiant heat and modcon was chosen for, But in the meantime it kind of leaked out though i didnt want to hear it right away that between now and a few years ago when i read all over this blog the TT110 was the baddest boiler ever.That boilers have doubled or quadrupled their modulation since.
Now on one hand im a humble guy asking you pros for DIY advice, but what im trying to say is there's rich guys out there that just want what they want, they got apps that do everything else they want and they are not going to be happy to find out they cant zone a master bedroom suit because its only 5000 btu and their fancy mod con only goes down to 30kbtu, and you think their desire is inappropriate, so some one is going to make a lot of money giving them what they want good and hot and expensive. But they are going to have their towel bar zoned by god or this aint america.
maybe they will have to make do with a buffer tank today but that's what i was told last year, today i am finding 10-1 and 20-1 boilers tomorrow im sure there will be no limitation whatsoever 0-100 i bet in five years.
Thank you for mentioning the tekmar thing I had learned in the course of this struggle that some boilers have similar control options to avoid calls below low mod by ganging calls they think are near need or something.
Listen harvey Im told i come of arrogant its the typing thing im very grateful you took the time to comment and i do understand you are simply relaying the limits of todays technology i get that im just saying things are going to change and soon

keyote

Hot rod it looks to me like this ochinvar can go down to 1 gpm and does work with variable speed pumps - that is if im understanding a cursory read.

Harvey Ramer

If anyone were to ask me, I'd say you're having a ball with this whole thing!

Carry on. It's my bedtime.

Gordy

Harvey Ramer said:

Which part?

Keynotes pm

keyote

LOL hey heres what i want HTP has a very similar option

keyote

I just hope when they say "variable speed pump they mean VT 2218.But I dont think they mean that but they dont say you cant Hot rod **** if the ecm gives the required flow you say the problem is the boilers computer cant handle the variable frequency? cant it simply send a on off signal or cant the pump be turned on off another way and the boiler just notified. anyone know someone at lochinvar i can drive crazy with stupid questions?

" Boiler circulating pump:
A Grundfos UPS15-58F pump for Models 55 - 155 and a
Grundfos UPS26-99FC for Models 199 - 285 will be
provided by the factory as the boiler circulation pump
based on 20 feet of piping, 4 - 90° elbows, and 2 - fully
ported ball valves. Knight Fire Tube boilers are capable
of controlling a variable speed boiler circulator. Variable
speed circulators MUST be sized to meet the specified
minimum flow requirements listed in Table 6B on page
38 at full speed.

Model Minimum
Pipe Diameter
Maximum
Flow
Minimum Flow
(High Fire)
Minimum Flow
(Low Fire)
55 1" 17 gpm 2.1 gpm 1.0 gpm
85 1" 17 gpm 3.2 gpm 1.0 gpm
110 1" 17 gpm 4.2 gpm 1.0 gpm
155 1" 17 gpm 5.9 gpm 1.0 gpm
199 1 1/4" 27 gpm 7.6 gpm 1.5 gpm
285 1 1/4" 27 gpm 10.8 gpm 1.5 gpm

Variable speed pump setup
Before operation, ensure the following:
- Pump is set for an input signal of 0 - 10Vdc by the dip
switches on the pump control
- Pump is set for external signal control (if applicable)
- Pump is set for linear output (if applicable)
- If pump does not come equipped with a 0 - 10 Vdc input
option, an optional module will be required from the
vendor"

hot_rod

We are getting mixed signals on exactly what you want? If you want zoning, reset, 10-1, optimized controls with ramp delay functions and online access, adequate DHW, etc that will not come cheap.

If you have the TT110, and a 30 gallon tank.. why not use that package?

The 3/4 connections on the tank are not a deal breaker, many of the mod con boilers have 3/4 ports with increaser nipples.

I doubt that you will ever get a consensus here as to which products, or piping and control methods are perfect. I have not read any bad suggestions other than the ones you got before arriving here
I like zoning also, especially in your case with your lifestyle and potential and unknown tenant schedules and lifestyles.

If zoning with valves then my preference would be the correct delta P circulator. Proper piping and balancing of the loops and zones will keep the ∆T in line, don't over think or complicate that part.

All hydronic systems strive for and find a point of thermal equilibrium, page 51.
But now we are back to the basics of hydronic design. I'd caution you to understand these basics before you get to bound up in complicated design options.


http://www.caleffi.com/sites/default/files/coll_attach_file/idronics_12_0.pdf

keyote

But this implies a ecm not a 3 speed doesnt it? it says " to maintain a minimum delta T" or is it saying it can make a three speed do what an ecm does with the current it gives it and its own system monitoring?

Variable speed system pump
If a variable speed pump is used in the primary loop, and a
0-10V signal is available from the pump speed control, this
signal can be used by the SMART SYSTEM control to anticipate
changes in the building heat load. By connecting this 0 - 10V
signal to the 0 - 10V SYS PUMP IN terminals, the boiler (or
cascade) can modulate up and down as the primary flow
increases and decreases.
Boiler pump speed output
This 0 - 10V output is available to control the speed of a variable
speed boiler pump. The SMART SYSTEM control will vary
the speed of this pump in order to maintain a minimum T
across the heat exchanger, as well as prevent high limit lockouts
when the flow in the primary loop is extremely low. Note: This
feature is to be used with Primary Secondary Piping systems
only. A system supply sensor must be installed. Connect this
output to the 0 - 10V input on the boiler pump speed control.
Rate output
This output provides a 0 - 10V signal that is proportional to the
firing rate of the boiler. This may be used by a BMS system to
monitor the actual rate of the boiler.

Gordy

The boiler pump needs to be tied to the modulation for success.

The uft comes with out an onboard pump. VS pumps are quite pricey.

keyote

This seem to be the answer from tacos site
:
Can you vary the speed of the Viridian using a 0-10 Volt DC signal?

Answer: The Viridian is capable of being turned on and off using 0-10 Volt DC signal. You are not able to actually change the speed of the pump based on a change in the DC voltage. See "Can I control the Viridian using a DC signal?" in the Viridian FAQ section.
which i think means the lochinvar control can tell the vt2218 tu run or stop but cant use lochinvars own pump speed controller and system sensors, but i as i understand it the VT 2218 uses its own supply and return sensors to control its own damn self on the delta t you program, so it ought to work i would think except the minimum flow issue even with a differential bypass is not necessarily going to be covered by a delta t setting, a delta p pump might work but i think im right on the cusp of the curve even with new flow head. if its the 1 gallon per minute low fire i need worry about or the high fire i wonder if i could fool it by putting the return sensor on the bypass. does that make sense?
It would help to pump into the boiler as shown i would think and
there may be a way to set a minimum flow as well?
or would the diff bypass just work?

SWEI

We have been waiting for a decade now on some small ECM circulator options with 0-10V control.

keyote

well this from taco is probably the answer but i have no idea what it means

"Minimum flow applications (low mass boilers for example).

Answer: For applications where minimum flow is a concern, the low flow differential head can be increased by increasing the H max or changing the slope of the pump curve (% proportional). In addition, the Viridian can be set to constant and any of the 12 speeds may be selected (more for constant flow applications)."
i think it means i can fix the problem by destroying the whole ecm point by lobotomizing it or i can set a differential bypass minimum, can i be that lucky?

Is this the same pump and boiler combo that hatteras guy was upset with rich about or was it this with an HTP? i couldn't figure out if rich or the mad hatter was right they were both quite sure of themselves though it seemed like rich was a designer and the hatter a homeowner, it seemed to that some some fine winter day they ought to settle it with a caucus race

Gordy

The htp uft has no on board circulator. Some have had success trying to mimic what a true 0-10v circulator set up should do as to modulating the flow, and the fire with out the 0-10v connection using the 2218.

It takes mass to get down in the 1gpm 7500 btu low end of that particular boiler with out short cycling. With any boiler. The disconnect becomes the response of the circulator to a change in delta is quicker than the boilers logic response to the modulation change. With low mass systems like base board. It becomes a dog chasing its tail.

Case and point if only one zone calls that is below 1 gpm, and the btu requirement is below the minimum btu of the lowest modulation your screwed. That's where the buffer comes in. If needed.
As SWEI pointed out the true marriage of an ECM variety circulator capable of this 0-10 v logic. has been in the waiting for quite some time. Across the pond its been around viessmann has done it as hot rod pointed out for years. The vitodens 200 is a prime example.

The VS circulator I posted literature on from taco is just the 00 family with the 0-10v logic all to big for an onboard swap out in a mod/con boiler. Very pricey also. All of this still needs an out of the boiler interface to tell the circulator what the boiler needs for flow. Which adds even more cost. So even with 0-10v capability for the circulator, and the boiler there is still another element to make them actually talk to one another properly. Unless I have missed something.

If the boiler selection has controls as Harvey pointed out to force the boiler to stay in a certain modulation step for extended periods before stepping up it helps. Being able to lock out a top end range etc. you really have to read the I/O manual on the controls of each boiler, and think about what options work to an advantage with certain types of systems, and how the systems are used. It's not a cake walk until you become fluent, and grasp what the programming can do if it is a part of the boiler package.

Your scathing countless threads, and debates of mod/cons on this site. Many great minds opinions. Many people fluent with their favorite boiler (s). Many ways to get from point A to B. You must become one with the system, and the boiler, and think like water. It's stupid, and lazy has to be told where to go........

Rich_49

I believe the circ you mentioned above is the VR1816 ( 12 speeds) not the VT2218 . The VR is a P circ while the VT is a Delta T circ . The VT can be used without Delta T enabled at a fixed speed .
The Vt is the circ being used with the UFT that was discussed by myself and HatterasGuy .

Do you remember any of the names of the folks you spoke to at HTP by the way ?

Gordy

Also you have to remember there are many elements that go into a circ design. A one size fits all is impossible. Some needs benefit from delta p, delta t, set point, variable speed injection. That's types. Add curves for systems into the element.

keyote

Rich you mentioned re; the hatters guy, that there was a way to make it work, is locking out the the DT feature what you meant? wouldn't this defeat the advantage of the ecm? Reading the lochinvar and HTP manuals I interpret them as able to use variable speed pumps using half a dozen techniques to overcome the minimum flow and 1-10 v issues, never the less you guys have actually had problems it seems, i'm trying to figure out whats what, have the manufacturers updated, or is it that im not understanding that issues will arise despite their assertions to the contrary a plain reading would interpret.

Thank you Gordy,
The VR1816 is available for the price of an alpha at HD [but at supply house they say its been discontinued, so i hope there was not problem with it].
I am within its proportional pressure mode curve including boiler drop.The VT2218 leaves a bit more leeway.

I think i understand you are saying the low flow call and high fire start up, may cause a delta T pump to be met so quickly it short cycles or locks out. But i thought it is supposed to respond by pumping faster and maintain DT, or do you mean that the boiler shuts itself and the pump off before the pump can catch up?
and then what does this language from lochinvar mean then?
" Ramp delay
For systems with lower flow, the SMART SYSTEM can
limit the firing rate (when enabled) when a space heating
call for heat starts, or when switching from a DHW call for
heat to a space heating call for heat. There are six (6) limits
that can be programmed, as well as six (6) time intervals
corresponding to each limit. The sixth limit will also limit
the firing rate for the rest of the call for heat.
Gradient limiting
If during operation of the boiler the outlet water temperature
is rising too quickly, the control will reduce the firing rate to
its lowest setting."

I am wondering if these pumps have a minimum that is above the boilers minimum, the curve seems to me to indicate that if i am interpreting it right, and i would think that extra flow could be routed with a differential bypass to the boiler. In fact i would think that a diff by pass could be set up as a zone if need be that came on when any other zone opens, isnt that what Diff bypass does in a sense ?
The boilers manuals to my novice mind say the boiler pump control will also maintain boiler minimums, and they have the ramp features, and the pumps manual say they have the ability to raise the curves for the flow issue. Im not trying to be argumentative i just dont get why you guys who i can tell know what you are talking about say it wont work and the manual seems to be offering all sorts of solution, I have to conclude youre saying the manuals are full of it, or that i dont understand what im reading, so since the latter is the likeliest i keep asking for clarification.
Both units have a six step ramp feature and 0-10 v outside control ability both have some language about low flow applications do able and both have a piping detail without P/S.

Im sorry if i have posted too much, or seem scathing, i have tried to be humble and polite and ask for clarification, Im acutely aware this is free advice done in service for fun and mutual education, its a complicated topic for a comment section.I had no idea it would get so complicated, its been really frustrating. i dont think im asking for something that should be so difficult its simply a large home with radiant heat, a concept promoted in journals and websites throughout the industry. Yes at one point i was trying to make an oversized boiler work but even when i get a right sized boiler with 10-1 modulation i find that the smallest zone it can handle is two floors on a spring day. That's twice as large as many homes. But they are selling actuators as zone valves are they expecting them to be used on 2000" loops? Oh sure i can run multiple pumps and loops to make it work but i might as well go back to zoning with windows if thats the game. As consumers we are sold this ideal of high tech green thats just not a reality. Whats more is i know in europe it works I know on airside we have been using variable speed [vfd] and [ecm] pumps and fans for at least a decade at the commercial level. I simply can not conceive how a modcon can not hand a variable speed pump in the current year, so yeah when Harvey said "appropriately zoned" i gave him some cheerful guff I apologize to him and the crew who have been so patient with mt if it didn't come off as jocularly as i intended it.

Rich_49

I will not comment on how that gentlemans system is not a good example of how a UFT or any mod con can or is supposed to work with a Delta T circ . I'll say again that myself and others have not experienced what Hatteras has . There are many reasons for this phenomenon and I'll leave it there .

No , disabling Delta T function is not how it works , knowing how to design a system and / or take the proper precautions to insure what happened there does not in your / my system is the key . It involves taking temp , flow , head , modulation rates , pipe sizing all into account , existing emitters ,you know , a SYSTEMIC APPROACH .

Sitting on a bucket in front of a failed install will never do anything to fix it . Designing it and setting it up properly does wonders .

These circs are tools and one must know how to use tools properly , most do not

keyote

Rich Im in lochinvar university watching videos right now, one thing of detail im learning [besides the more general comments ive made in this thread quoting and paraphrasing both manuals on this topic] is in the pump parameter setting one setting is variable speed pump minimum voltage, they talk about setting the minimum voltage high enough to keep the DT across the HX to spec at all times and how it will decrease pump speed as fire decreases the voltage to maintain it and it also monitors outlet v system temp and will adjust to keep them 2 degrees apart.

Dont laugh but i think my idea for system is not bad, its basically the the two piping sketches i just posted in this thread from HTP and Lochinvar manual.
i started out wanting that same system as pictured in the TT110 manual. but that boiler had a high minimum flow.
The concept to me is simple if i have total flow and head that one pump can handle i dont want to use more than one pump. Gordy showed me how i could get flow/head down by going to a wider delta they are now at DT15 7.2 flow 6.7 head plus boiler drop. well within almost any variable pump though the VT2218 seems to me the to afford better margin of error or system expansion, i also find it easier to think about control knowing the pump is taking care of the dt and the boiler can take care of water temp. Though thats because im an idiot not a designer.
So i accepted P/S with the TT but still was oversized. it wasnt simply that i was too cheap to buy a new boiler i didnt want to buy it until i had seen the system in actual operation and until the renovation was over, so i tried the buffer thing but when it got as expensive as a new 10-1 modcon that seemed crazy.But here i am with my right sized boiler that even mods 10-1, my right sized pump and system, willing and wanting to follow the manufacturers straight through piping plan but i still am told i cant use a variable with a modcon without P/S &^%$#$%

i have it all in loop cad with every imaginable flow temp head dt imaginable i have changed design day to 60 degrees to see what a low load in spring looks like, i can look at every loop manifold riser or total and get the numbers for that. I have read Siggys and Holorans books and been in the airside of the Biz my whole life. Im reading the manuals that seem to me to say theres no problem, yet guys are saying there is, i dont know what to think. You at least say there's no problem if simply done correctly, I think im doing it correctly. Hot rod who works for caleffi seems to think the electronics don't communicate properly,Now that is not a matter of did i size my header right do i know the load of my smallest zone or match the pump curb to the head, thats a matter of the damn electronics of the two machines dont speak same language. Gordy thinks the problem is more about the minimum flow, the pump cycling and fire modulating all fast enough and coordinated enough to not lockout or cycle. But the manuals again seeeeeeeeeeem to me to say they got it covered. The two diagrams show a differential bypass, theres several other control parameters that seem to me to be directed at exactly what we are talking about - and yet very smart guys say no. meantime im told im not zoning appropriately because id like less than a 2500 sf zone in a state of the art system with a 10-1 modcom radiant floors and ecm pumps and 2500 sf is the best i can get without running multiple pumps but im being difficult. Look i love you guys this websit siggys books and dans books im addicted to this kind of stuff anyway then i found you guys a few years ago . you guys didnt design pumps and boilers that dont match but im frustrated, for thirty years ive read of the wonders of radiant heat mod cons and lately ecms and come to find i might as well use a big window if i want zoning because basically all we can do is overbuild and open a window,

Rich_49

Forget about the DBPV , they are for zoned systems w/o ECM / VS circs . Got it , you don't require one , unless you use a single speed PSC circ .

Zones are not determined by sq ft , instead rooms that have similar BTU sf requirements , similar finish floor R values can be on the same zone , if those criteria are not met you WILL sacrifice some comfort .