Mod CON? Or Power vent 85%?

Gordy

^ that's reassuring..........

Suzook

NY_Rob said:

Two final thoughts...

-Don't use Pex for the near boiler piping.

-If you need to call HTP support - if you get "Peter" on the phone... hang up wait a bit and retry for someone else who might actually be helpful.

Ok, pex will be run to old existing plumbing....Is about 8 feet out from boiler ok for copper?

NY_Rob

^ yeah, when the "official support rep" tells you things like below it doesn't exactly inspire confidence:

"a boiler can't just keep running all day"
...isn't that the point of a mod-con? Run it 21hrs/day...

"the factory default reset curve is perfect.. don't change it"
...how could he possibly know what my house needs to match heatloss? The default curve would be a disaster with my setup.

"don't bother using an outdoor reset sensor"
... okay, so just run at 180F SWT all the time like he does on his UFT-199W mod-con.

"you must have a really special house if you can heat it with 110F water"
... when it's 50F outside- you don't need 180F SWT.... do you?

"I don't care if it's condensing or not"
... well, that won't be an issue with a fixed 180F SWT!

Then he completely dismissed an issue I was having where a later phone call to the next rep informed me that it was a known issue and was easily corrected with the latest FW (from last summer) on a new controller board- which HTP furnished under warranty.

So, yeah... you can do better than Peter.

ratio

facepalm! (Don't have that swell graphic on this computer, sorry)

Suzook

Doesn't anyone think it's pretty stupid that a fw update is only possible by changing the main board??

NY_Rob

^ yes, in 2017 it's really poor... but it's a budget boiler.
It's microprocessor probably has a very common i2c two-wire or four wire SPI interface that could easily connect to any computer with a $10 USB dongle for in-the-field updating.

On the upside... they had a fix for my issue, and they provided a no charge replacement part.

Suzook

NY_Rob said:

^ yes, in 2017 it's really poor... but it's a budget boiler.
It's microprocessor probably has a very common i2c two-wire or four wire SPI interface that could easily connect to any computer with a $10 USB dongle for in-the-field updating.

On the upside... they had a fix for my issue, and they provided a no charge replacement part.

That's true, I guess you can't have everything for this price point. I will be sure to check the fw when I have it set up.

Suzook

@NY_Rob another quick question on venting. I am assuming by your name, and letting me know about blackman, ou are from NY....I will be hoping to side vent. There is a walkway 4 ft from the house in the backyard, and there is also a an overhang of 2 feet deep which is not vented....From what i have gathered 1 foot below the overhang is required?? Or is it more? Thanks again

Rich

NY_Rob

^ From page 27 of the install manual...
"For every 1” of overhang, the exhaust vent must be located 1” vertical below overhang".
There are illustrations on the same page.
To me that means with a 24" overhang the vent must be at least 24" below the overhang.

Venting is complicated, take your time choosing vent location. The slope has to be right in order for condensate to flow back into the boiler and not collect and freeze in the pipe during winter, you also have to protect against dust, dirt in the intake, and of course stray CO is a big concern.

BTW- one thing they don't mention in the install manual is that in addition to a maximum length of pipe for 2" or 3" PVC... there is also a minimum length. My boiler is very close to the outside wall, my whole intake and exhaust system was made from one 10' section of 2" pipe... with some left over. I had already decided to go with 2" pipe because the runs were very short, and a call to HTP support confirmed that I would have run into problems if I had used 3" pipe on that short run. IIRC the minimum length of 2" pipe you can use is 8', I don't know what the minimum is for 3" pipe. But if you have very short runs... go with 2" pipe.

Download the current install manual here:
http://www.htproducts.com/literature/lp-542.pdf
Keep it handy, you'll need to refer to it often during the install and commissioning.

CMadatMe

I don't come on here much anymore but each time I get a great chuckle over the Mod/Con vs Standard Fixed Rate Boiler debate. Any boiler no matter its style has one job, make energy. That's it..

Questions really are what amount of energy do you need, how effective is the entire system in order to use the energy created and what's the best means of eliminating waste. Lot more to a heating system then a boiler.

Suzook

Chris said:

I don't come on here much anymore but each time I get a great chuckle over the Mod/Con vs Standard Fixed Rate Boiler debate. Any boiler no matter its style has one job, make energy. That's it..

Questions really are what amount of energy do you need, how effective is the entire system in order to use the energy created and what's the best means of eliminating waste. Lot more to a heating system then a boiler.

While yes I agree a boiler has only one job, there are alot of variables, hence the Mod/Con vs Standard. Its not that simple really. The main issue is getting "old school" plumbers into the future. With the price of todays Mod/Cons I believe we are headed there.

Rich_49

Chris said:

I don't come on here much anymore but each time I get a great chuckle over the Mod/Con vs Standard Fixed Rate Boiler debate. Any boiler no matter its style has one job, make energy. That's it..

Questions really are what amount of energy do you need, how effective is the entire system in order to use the energy created and what's the best means of eliminating waste. Lot more to a heating system then a boiler.

Energy cannot be created nor destroyed Chris , it can only change forms . I think the word you were looking for was , heat

Suzook

Thoughts???

Gordy

The focus of the debate always ends up skin deep. Initial cost of the different boilers for an extra 10% efficiency, their longevity, and maintenance cost differences. Gotta dig deeper to the total system performance. Including the envelope.



Someday we will have to explain why our choices were what they were to future generations that will be left holding the cost of energy bag.

Some will argue that ROI is always the driving factor. Is it?

Suzook

> @Gordy said:
> The focus of the debate always ends up skin deep. Initial cost of the different boilers for an extra 10% efficiency, their longevity, and maintenance cost differences. Gotta dig deeper to the total system performance. Including the envelope.
>
>
>
> Someday we will have to explain why our choices were what they were to future generations that will be left holding the cost of energy bag.
>
> Some will argue that ROI is always the driving factor. Is it?

I agree, but the cost of this particular mod/con and probably future ones is the same as a standard boiler. Maintenance will be done by me, so that's not an issue. My only issue is longevity, but hoping with proper maintenance should last 20 yrs??? While not 30 or more like standard, what today lasts as long as "the old ones"?? And my envelope is as tight as can be without ripping out my sheetrock walls, which I won't be doing. In the end, I will be gaining space, AND getting rid of oil.

Gordy

The gap is narrowing on initial costs. It is sad that what seems to be gained in efficiency in many things across the board can be lost to longevity. Then there is the whole cradle to grave argument on a lot of those things.

Example: ripping out perfectly good wall assemblies for the sole purpose to insulate, or ripping out working windows to replace with more efficient new ones. The opportunity will lend itself at the proper time.

Gordy

Suzook said:

Thoughts???

You'll want the alpha in constant pressure mode with zone valves. Another choice would be the taco viridian 1816 in constant pressure mode.

NY_Rob

^ the problem with the factory diagram is that for five + months of the year (once you no longer need space heating) when you're using the boiler for just domestic hot water you are bypassing the dirt strainer and air remover. Fire tube mod-cons, well at least the HTP UFT-W80- by design creates micro-bubbles that constantly need to be removed. Bad idea to bypass the air/dirt strainer for five months and have no way to remove air and dirt from the system.

If you make a slight modification... you'll run fine because all water will flow through the air/dirt strainer 24/7/365...

NY_Rob

^ With the above diagram- be sure to install the flow check valves in the pumps!

As Gordy mentioned... keep the CH pump in CP mode.

Solid_Fuel_Man

Have you looked at the WeilMcLain 90+3? If you decided to go CI that would be my option. Although I believe in mod-cons for most cases.

Gordy

There should come a point where you should not have to constantly remove air in the system if there are no leaks, and no makeup water being added repeatedly. However if the airsep is at the high point above boiler any significant air bubbles should end up in the airStep in the non heating season No?

NY_Rob

^ I found with the HTP UFT-80W when it's throwing all 80K BTU's at the heat exchanger for DHW- even with 7-8GPM flowing through the HX... micro bubbles will form over time.
I know two other people w/the same boiler... that have both noted the same thing happening at max fire rate. It manifests as an occasional "perk" sound inside the boiler.

I believe it's due to the design of the HTP fire tube HX.
You have 1500F+ super hot air running through multiple thin walled stainless steel tubes encased in water. At the point where the water contacts the hot fire tube surface... micro bubbles form due to boiling. There are probably some areas that either don't get enough flow to prevent micro-hot spots and boiling, or there are hot spots that boil regardless of flow.
It's not noticeable on the UFT-80W at lower fire rates, but at full 80K BTU output you will get bubbles over time.

It's nothing the air/dirt sep can't handle, but the factory diagram takes the air/dirt sep out of the loop for the spring and summer seasons.

FWIW- I've had my make-up water valve closed since Dec... it's still at 15PSI and holding.... and I still hear an occasional "perk" when the DWH call is near the end of the cycle, as other UFT-80W owners have also noted.

Suzook

NY_Rob said:

^ the problem with the factory diagram is that for five + months of the year (once you no longer need space heating) when you're using the boiler for just domestic hot water you are bypassing the dirt strainer and air remover. Fire tube mod-cons, well at least the HTP UFT-W80- by design creates micro-bubbles that constantly need to be removed. Bad idea to bypass the air/dirt strainer for five months and have no way to remove air and dirt from the system.

If you make a slight modification... you'll run fine because all water will flow through the air/dirt strainer 24/7/365...

NY_Rob said:

^ With the above diagram- be sure to install the flow check valves in the pumps!

As Gordy mentioned... keep the CH pump in CP mode.

Great info!! Since I only have 2 zones, would I be better off with 2 circ pumps instead of the zone valves? It's a few bucks more,but not much. I could also get rid of the diff pressure bypass valve.

Gordy

Maybe you should ask Peter about that

It seems to me no manufacturer would want hot spots in their HX especially when piped per I/O manual.

What you may be experiencing is the lower temp CH fluid not yet seeing the higher temp DHW calls, and bringing air out of solution. Depending on CH volume could take a very long time for that fluid to be exposed to the hottest temps it could ever see. Just a theory though.

NY_Rob

^ he told me it's normal...lol

Gordy

Suzook said:

NY_Rob said:

^ the problem with the factory diagram is that for five + months of the year (once you no longer need space heating) when you're using the boiler for just domestic hot water you are bypassing the dirt strainer and air remover. Fire tube mod-cons, well at least the HTP UFT-W80- by design creates micro-bubbles that constantly need to be removed. Bad idea to bypass the air/dirt strainer for five months and have no way to remove air and dirt from the system.

If you make a slight modification... you'll run fine because all water will flow through the air/dirt strainer 24/7/365...

NY_Rob said:

^ With the above diagram- be sure to install the flow check valves in the pumps!

As Gordy mentioned... keep the CH pump in CP mode.

Great info!! Since I only have 2 zones, would I be better off with 2 circ pumps instead of the zone valves? It's a few bucks more,but not much. I could also get rid of the diff pressure bypass valve.

The whole idea of using an ecm circ that has a constant pressure capability delta p is to eliminate the differential bypass. So using the alpha, or viridian no you do not need that DBV.

NY_Rob

Suzook said:

...Since I only have 2 zones, would I be better off with 2 circ pumps instead of the zone valves? It's a few bucks more,but not much. I could also get rid of the diff pressure bypass valve.

My zones were fairly close in loop length, so the Alpha in CP mode worked out for me.

I don't recall seeing your actual loop lengths (not the fin tube lengths)?
If you go with zone valves and one pump, you may have to throttle the short zone a bit with a globe valve if that zone has a much lower head figure than your long zone. You don't want the short zone flowing 3gpm and the long zone flowing 1gpm when both zones are active.

Suzook

Gordy said:

Suzook said:

NY_Rob said:

^ the problem with the factory diagram is that for five + months of the year (once you no longer need space heating) when you're using the boiler for just domestic hot water you are bypassing the dirt strainer and air remover. Fire tube mod-cons, well at least the HTP UFT-W80- by design creates micro-bubbles that constantly need to be removed. Bad idea to bypass the air/dirt strainer for five months and have no way to remove air and dirt from the system.

If you make a slight modification... you'll run fine because all water will flow through the air/dirt strainer 24/7/365...

NY_Rob said:

^ With the above diagram- be sure to install the flow check valves in the pumps!

As Gordy mentioned... keep the CH pump in CP mode.

Great info!! Since I only have 2 zones, would I be better off with 2 circ pumps instead of the zone valves? It's a few bucks more,but not much. I could also get rid of the diff pressure bypass valve.

The whole idea of using an ecm circ that has a constant pressure capability delta p is to eliminate the differential bypass. So using the alpha, or viridian no you do not need that DBV.

So I can eliminate the DBV?

NY_Rob said:

Suzook said:

...Since I only have 2 zones, would I be better off with 2 circ pumps instead of the zone valves? It's a few bucks more,but not much. I could also get rid of the diff pressure bypass valve.

My zones were fairly close in loop length, so the Alpha in CP mode worked out for me.

I don't recall seeing your actual loop lengths (not the fin tube lengths)?
If you go with zone valves and one pump, you may have to throttle the short zone a bit with a globe valve if that zone has a much lower head figure than your long zone. You don't want the short zone flowing 3gpm and the long zone flowing 1gpm when both zones are active.

I never stated length. The second less BTU zone is just about the same length, and is feeding the second floor. Just trying to figure out is 2 pumps is better for me, or 1pump and 2zone valves.

Jamie Hall

I'm fascinated by the comment "My 35%+ fuel savings is not efficiency or AFUE, it's out of pocket monthly fuel savings based on lower BTU consumption due to the fact that modulating burners can modulate down to the heat load but non-modulating CI's are on/off. ". And what, exactly, do people (not necessarily @gschallert) -- in general -- think is happening when a boiler cycles on and off? That, my friend, is a form of modulation. It's called pulse width modulation in the electronics world, and works. It is true that there is a small loss of efficiency -- if the off timing is long enough to let the boiler cool significantly -- but otherwise? A percent or two at most.

I am not opposed to mod/con boilers -- it would be very nice if I had a modulating oil burner for Cedric, but they're a bit thin on the ground. They are more complex, and need better maintenance, it's true -- but given that they are fine.

I would point out that there is no reason why a boiler with a on/off burner cannot (and perhaps should not!) be modulated using pulse width modulating -- particularly if it is gas fired -- to maintain condensing conditions.

The quoted efficiency gains are from the ability to maintain condensing conditions in the exhaust. Not because the burner modulates.

Please. Let's make sure that our arguments are based on sound engineering -- or true apples to apples comparisons (that is, in the present case, identical buildings with identical occupancies and identical exposures, and identical emitters and piping etc. etc., but one with (in the immediate instance) with a mod/con with properly managed controls and the other with a non-modulating boiler -- again with optimized controls.

Solid_Fuel_Man

The problem I would think is the stack losses in any CI boiler are many times what a mod-con would be. Consider this, let a boiler maintain normal operating temperature (180 or so for water, and 212 for streamers), without a call. I know the steamers just need to be hot but not steaming. Measure the cycle time the burner runs and the off time between. That is almost exclusively stack loss chimney heating.

Motorized flue dampers help this loss, always wondered why they are not available as CI on oil equipment. Maybe not worth the added complexity.

ChrisJ

Solid_Fuel_Man said:

The problem I would think is the stack losses in any CI boiler are many times what a mod-con would be. Consider this, let a boiler maintain normal operating temperature (180 or so for water, and 212 for streamers), without a call. I know the steamers just need to be hot but not steaming. Measure the cycle time the burner runs and the off time between. That is almost exclusively stack loss chimney heating.



Motorized flue dampers help this loss, always wondered why they are not available as CI on oil equipment. Maybe not worth the added complexity.

I suspect because oil has air forced into the chamber and once that blower stops the draft dies almost immediately.

All of the oil burners I've seen have the barometrics flop wide open when the burner shuts off and then slowly close.

Jamie Hall

Stack loss certainly is a factor, and I don't recall having seen it really seriously quantified anywhere. There are a number of variables (even with a steamer, where it will be more significant). Things to consider are is it natural draught? If so, is there a barometric damper on the breeching (makes a huge difference, since it will kill the chimney draught)? How tight is the whole thing (power burners, for instance, have a relatively small air flow when the primary and/or secondary air blower(s) are off)? Is there a stack damper which closes after the post-purge (if any)? (I've always hated those things -- the least reliable bit on the system, and seemingly they choose to fail shut when it's 20 below and howling outside!). Is there a post-purge?

So many variables. It would be nice to see some real hard numbers on them.

Solid_Fuel_Man

The engineer in me wants all the btu's in the water and not leaving the structure via the flue!

ChrisJ

Solid_Fuel_Man said:

The engineer in me wants all the btu's in the water and not leaving the structure via the flue!

Tell us, how does entropy make you feel?

Jamie Hall

ChrisJ said:

Solid_Fuel_Man said:

The engineer in me wants all the btu's in the water and not leaving the structure via the flue!

Tell us, how does entropy make you feel?

Disorganized?

ChrisJ

Hot water boiler is 100% efficient.
Heat pump is allegedly more than 100%.........

Gordy

The huge percent savings if one reads between the lines of the claims ends up being a right size boiler replacing a grossly over sized boiler, and the condensing which can account for 5 plus % of that depending on the return temps to the mod/con boiler. Also for those that sometimes do not take into account the fuel cost differences from say switching from oil to gas.

The only true apples comparison is if both boilers ci and mod/con are exactly matched to the heat loss.

Off time can account for a large deficit in efficiency on a ci boiler. As Taylor points out. How large is debatable, and lacks detailed supporting evidence. This deficit can be directly linked to how over sized a ci boiler is to the heatloss. More HX mass, and water content to reheat if the call allows the boiler to cool to ambient conditions, we have all seen boilers twice or more the size needed for the load. Throw zoning, in the mix.......

Again you can't get way from a btu is a btu. However it does come down to gross input verses net output. How efficiently those btus are made, and how efficient the entire " system" is at distributing them.

What gets me is that some say I'll only save 100 dollars a year. Now think of it collectively city wide, state wide, country, world wide. That's not peanuts. Every little bit adds up to huge energy savings in the big picture.

ChrisJ

@Gordy Not sure if you're talking about me when you say "what gets me is that some say I'll only save 100 dollars a year. Now think of it collectively city wide, state wide, country, world wide. That's not peanuts. Every little bit adds up to huge energy savings in the big picture."


Sure, it adds up when a few million people do it, but those other people aren't responsible for putting food on my table. You had an argument with me that I should dump X amount into my house which would take me 111 years to ROI and I told you that wasn't practical.

It still isn't.

Solid_Fuel_Man

That $100 a year mentality is why there are some who would like to see US fuel prices to skyrocket. Therefore giving incentive to conserve. I don't agree with that line of thinking at all, but as stated before I want as many of those btu's input to the system to be delivered into the building envelope. We all know the heat plant is just one piece of that equation.

I have an "efficient" direct vent sealed combustion Toyotomi oil boiler specifically made to be DV. And I will tell you that even with a 130 degree water temp my hand stays nice and warm when I'm outside the house with my hand above that exhaust opening. And that's with a restrictive 2 stage combustion fan and 3" flue concentric vent. I built the control to run my radiant at the end of any call for heat until the boiler reaches 90 degrees. All with 8 pin ice cube relays and aquastats. Basically ano Energy Kenetics heat purge.

ChrisJ

@Solid_Fuel_Man I have to ask, with your name, why are you using oil?

I assumed you used coal or wood.