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# [long! read only if you're bored/have time] mod/con boiler if i don't want one

#161
03-26-13, 02:30 PM
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what are the pros/cons for zone valve 24 VDC vs 115 VAC voltage?
24-V can be routed with regular thermostat wire. A 24-V transformer of suitable VA rating is required.

In general, 120-V wiring must be routed in conduit. Exposed, stapled up, or draped Romex or building wire can't be used. No transformer is required. You would need 120-V thermostats or relays. Not very practical.

Last edited by gilmorrie; 03-26-13 at 03:09 PM.
#162
03-26-13, 03:03 PM
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http://s3.pexsupply.com/manuals/1350..._PROD_FILE.pdf

#163
03-27-13, 09:20 AM
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Diver, a while back you posted this:

Dynamic head is always a function of the flow and in the calculation i've seen so far for hydronic system it was liner feet multiplied by 0.04. I was a bit puzzled, since there was no flow specified. I think 4 gpm was implied.
It didn't appear to have received any notice. I would like to clear a couple things up about it...

the calculation i've seen so far for hydronic system it was liner feet multiplied by 0.04
For pipe with no fittings, yes. If you want to APPROXIMATE the head of a SYSTEM with all the elbows, valves, etc, one would measure all the straight pipe, and MULTIPLY BY 1.5 to APPROXIMATE the TEL (Total Equivalent Length) of the circuit.

Then multiply by 0.04.

I think 4 gpm was implied
Only if you are dealing with 3/4" pipe.

That 0.04 represents FOUR FEET OF HEAD per 100 FT of PIPE.

This works with other sizes of pipe as well, but does not represent 4 GPM.

It would approximate the head that would be present with the water moving at FOUR FEET PER SECOND.

In other words, for 1/2" through 1-1/4" pipe, water at a velocity of 4 FPS will generate approximately 4 FT of head per 100 FT of pipe.

Remember, this is an approximation that is usually good enough for gummint work.

#164
03-27-13, 09:34 AM
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thanks NJ Trooper.

in the document i referenced before they use flow rate in the pipe to figure out the head which is more realistic.

#165
03-27-13, 10:21 AM
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Yes, it is more realistic... I just wanted to clear up your statement a bit and for others who may read.

Still, how accurate does one need to be to select a circulator?

#166
03-27-13, 12:35 PM
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as accurate as much time and/or desire to go into details they have

#167
03-27-13, 04:31 PM
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Still, how accurate does one need to be to select a circulator?
as accurate as much time and/or desire to go into details they have
At some point, I think it becomes obsessive-compulsive. But if you don't think you are there yet, here are some additional factors haven't considered yet:

The pressure drop through a pipe is directly proportional to the friction factor, which, in turn, depends upon the relative roughness of the internal pipe wall. The relative roughness will increase as the pipe ages due to corrosion and incrustation. This data is readily available in the literature.

With incrustation, the effective pipe inside diameter will decrease. For example, a mere 2% decrease in diameter will increase pressure drop by about 11%. You can measure the pipe diameter with an inside micrometer.

And then when you go to replace your boiler, it will likely be supplied with a circulator, probably a garden-variety Taco 007. Then what?

#168
03-27-13, 04:37 PM
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But if you don't think you are there yet, here are some additional factors haven't considered yet

gilmorrie, i think you just got us "there"

i want to draw a final diagram with what i think i will go with and run it by folks here. and the i will stop obsessing with it. at least for a while

#169
03-27-13, 05:01 PM
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The suspense is killing me.....

I thought at one time in this thread R beck or someone just suggested 007's all around.... Done!!!!! Or maybe it was I....

Hope you dont throw us all for a loop and pick different equipment.....LOL.

Last edited by lawrosa; 03-27-13 at 08:45 PM.
#170
03-27-13, 05:09 PM
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and then i will stop obsessing with it. at least for a while
Don't be too hasty. When you finish with the friction factor and the diameter issues, I've got lots more. When you work through all of them, you will feel much more comfortable with the Taco 007 (that you were going to wind up with anyway).

#171
03-27-13, 05:15 PM
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gilmorrie, i think you just got us "there"
ha ha ha ... I think we passed that point a LONG time ago!

#172
03-28-13, 07:01 AM
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i want to draw a final diagram with what i think i will go with and run it by folks here.
OK, but please start a new thread with the diagram. This thread has become like a beagle chasing 10 rabbits.

#173
03-28-13, 07:53 AM
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will do, but it might take a while! thanks everyone!

#174
03-28-13, 06:29 PM
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Also don't forget that the resistance to flow changes with water temperature and velocity to really throw a wrench into the mix for more confusion. Add to that air reduces circulator head pressure which reduces flow. Reduce flow and reduce heat output from the radiation.

#175
03-29-13, 07:40 AM
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actually, i did correction for viscosity of the water at 180F

#176
04-05-13, 06:14 AM
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So all of you that say the VSP requires this special piping, does my current oil setup suffice for that or will it cost bigtime bucks to replace?

Here is a picture of my current direct vent peerless wv-dv 140k btu burner. It is all approved HVAC flex piping and such so could this be used for a coventional, non coden boiler?

#177
04-05-13, 08:59 AM
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i'm also a bit confused why AL29-4C venting is required for closed combustion non condensing boilers. i understand that flue gases are higher but they also are high in my regular atmospheric boiler and it uses an old fashion duct piping without any problems.

edit: i'm very tempted to go with Slant/Fin Victory VSPH-60. it's a good size for me, cheap and simple. it would not require primary/secondary piping and would fit right in into my existing system. the only problem is stupid AL29-4C venting requirement.

Last edited by _Diver; 04-05-13 at 10:18 AM.
#178
04-08-13, 05:41 PM
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The problem is not that the flue gas temps are so high that it forces the requirement for SS venting....
The problem is, some of these power vented appliances are getting up into the high 80 percent eff. area. When the eff. are this high and RWT's are lower, the boiler can operate at or near condensing point.
What then happens is the flue gases condense in the venting system, and it will rot it out in short order.
That flex venting has always scared the Cr*p outta me. It is good for some products sure but with the variables of a boiler and it's sensitivinty to low RWT's I would never use it in that application.
I mean after all you REALLY don't what your vent system rotten and leaking products of combustion into your home...

The AL29-4C provides great resistance to corrosion, especially that of NG flue gas condensation. I have seen lots of AL29-4C with leaks, but none it was to to perforation by corrosion

#179
04-10-13, 07:06 AM
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i guess the flue gases are still too hot for PVC, because PVC has excellent resistance to the flue gases condensate:

are there boilers that support direct combustion and exhaust via PVC or regular stainless steel ducts?

#180
04-10-13, 05:32 PM
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if you want to vent with plastic, you need to move to condensing. Flue gas is too high otherwise

#181
04-10-13, 05:48 PM
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i'm also a bit confused why AL29-4C venting is required for closed combustion non condensing boilers. i understand that flue gases are higher but they also are high in my regular atmospheric boiler and it uses an old fashion duct piping without any problems.
Best to call the manufacturer of the boiler you are intending to buy - ask them.

#182
04-11-13, 07:20 AM
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any opinion on Z-FLEX Z-Vent piping? it seems to be conforming to AL29-4C and 1/3 of the Heat-Fab cost:

2SVEPWCF0303 - Z-FLEX 2SVEPWCF0303 - 3" x 3' Z-Vent Pipe

Heat-Fab SC03L36 3" Saf-T Vent SC 36" Length

#183
04-11-13, 08:47 AM
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edit: i'm very tempted to go with Slant/Fin Victory VSPH-60.
Hmmmm... Not sure why you would want this but I understand your piping concern .

With That said I have been reading oodles of info on this GV-90. A 5 pass design in the cast heat exchanger, and two pass on the flue heat exchanger.

Additionally can accept water temps as low as 60F... Built in circ for boiler loop.

And is direct vent with PVC...... ( I believe we discussed this model before)

http://www.weil-mclain.com/en/assets...s_Brochure.pdf

GV90+ Gas Boiler | Weil-McLain | Product Detail

But smallest is 65K DOE.... How big is your existing boiler? I believe we said your baseboard is 50-55k so this boiler would be over sized by 10k

But !!!!!! I have not studied yet what controls it has, and/or outdoor reset capability's. I think with low return temps, that you can run this at low temps to make up for it being over sized.....

Just my opinion. I find the boiler interesting...

#184
04-11-13, 10:35 AM
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Lawrosa,

I was under impression that you’re a big proponent of Slant/fin products(boilers)? You mentioned Sentry on multiple occasions and Victory seems to be a direct combustion version of it. You liked metal push nipples and Honeywell controls. I believe they both use them.

My big dilemma was conventional vs. mod/con boilers. After hours of research and studying with help from this group and you as well, I settled for Peerless PF-50 as a mod/con boiler I would go with. GV was on my list, but I couldn’t form a good opinion on it except that it was a weird kind of a boiler. It’s cheaper than PF-50, but I’m afraid that’s the only thing it has going for it. I’m not sure I’m a big fan of primary/secondary exchangers. Seems like unnecessary complexity to me.

As for Victory, I want to pick a boiler if I decide to go with a conventional one and Victory bubble up to the top of my list. It’s small and simple. I could avoid using p/s piping with it. I emailed Slant/Fin and asked them for flow/pressure drop info for this boiler. I want to know if it’s possible to pipe IHW directly off the boiler as a simple parallel zone. If that’s the case, the whole installation/system could be very simple. One of the disadvantages of this boiler is the stupid AL29-4C requirement. That’s why I’m curious about Z-Flex piping.

Edit: just got an email from Slant/fin. They say pressure drop for the boiler is negligible (see below) and that the built in recir would be ok for the IHW.

Pressure drop across the boiler in a typical residential application is negligible (nothing really to calculate).

The boiler is shipped with a Taco 007 circulator.

Pump curve of the 007 appears to be O.K. for your tank.

Last edited by NJT; 04-11-13 at 11:33 AM.
#185
04-11-13, 12:12 PM
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I was under impression that you’re a big proponent of Slant/fin products(boilers)?
I like slant fin because of the controls.... Yes push nipples too, but the control that reads off the t stat thermal tageting. Plus its one of the only manufacturers that make a small boiler for my application in atmospheric vent. 30k or smaller.

It’s cheaper than PF-50, but I’m afraid that’s the only thing it has going for it.
The GV is what \$400 difference? I looked briefly...

I’m not sure I’m a big fan of primary/secondary exchangers.
The GV is a 5 pass cast iron exchanger. Thats impressive when most boilers are 3 pass I believe. Additionall the other exchager is simply a 2 pass flue design which is connected of the side. So 7 pass with 92% eff for cast iron venting in PVC.....

I emailed Slant/Fin and asked them for flow/pressure drop info for this boiler. I want to know if it’s possible to pipe IHW directly off the boiler as a simple parallel zone. If that’s the case, the whole installation/system could be very simple. One of the disadvantages of this boiler is the stupid AL29-4C requirement. That’s why I’m curious about Z-Flex piping.
Your delema is you need direct vent, or that is thats your preference. Because of this decision you choices are slim.

So the peerless fits perfect as a modcon goes.

The GV fits as a standard boiler that is direct vent with PVC.

Last the steel pipe boilers...you can pick and brand. They all have them more or less. But you will pay probably close to \$2000 plus labor added on to your price tag.

Do the math....

Edit: just got an email from Slant/fin. They say pressure drop for the boiler is negligible (see below) and that the built in recir would be ok for the IHW.
That boiler has a built in circ????? I belive it just ships with a 007 for the system, although I have not seen the instructions.

The GV actually has a built in boiler circ, so that will save the money of a pump and close space tees. But I need to look at the instructions again.

Additionally return temps to 60f.... For cast... Thats crazy....

Although I dislike other weil mclains this one interests me. Hey no push nipples, just check the exchanger warranty....

If they made a smaller one of these it would be on my own shortlist. And for me, to help you understand my thinking, is I myself will not spend \$3k for a mod con. Add on all the fittings, pumps..etc and you may be taking close to 4k. Plus maintenance costs. And that's me installing. I could get myself a slantfin for 1k with minimal parts, and total would be say \$1500 me installing with parts.

OK I said enough.....

#186
04-11-13, 01:06 PM
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lawrosa,

i think GV90+ for all intents and purposes is a condensing boiler. it has one exchanger that is condensing, and it has all the drawbacks of mod/con - p/s piping, condensate pump, high head, etc.

so my thinking is if i go for mod/con, i'd go with peerless pf-50. and you were one of the people who convinced me too!

slant/fin victory comes with a taco 007. it would be a direct replacement for my ancient repco la-100 and it's small enough. the smallest gv90+ 3 is pretty big.

victory will not require p/s piping, could work with one taco 007 recirc (comes with it) and 3 zones - IHW with priority and 2 CH zones. very simple. granted, no ODR, no condensing, but my gas bill is very low as it is with an extremely inefficient 100kbtu input atmospheric boiler. downsize almost by factor of 2 and i would rip big benefits already. i'm ok letting go small efficiency differences that would mod/con give me. they are bad ROI anyway

the only drawback of Victory is AL29-4C. The material for venting would probably be about \$300-\$400. I would think with the work it would together add about \$700-\$800, which is still reasonable. correct me if i'm wrong here.

so as i said before i'm tempted take a look at the brochure and installation instructions:

http://s3.pexsupply.com/product_file...oryVSPHBro.pdf

http://s3.pexsupply.com/manuals/1327..._PROD_FILE.pdf

if anyone had any first hand experience with Victory boiler, i'd love to hear it!

#187
04-11-13, 09:45 PM
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i think GV90+ for all intents and purposes is a condensing boiler. it has one exchanger that is condensing, and it has all the drawbacks of mod/con - p/s piping, condensate pump, high head, etc.

so my thinking is if i go for mod/con, i'd go with peerless pf-50. and you were one of the people who convinced me too!
No you dont pipe the GV p/s with basboard. Just in and out. No extra pump the internal pump is whats used for CH.

I recommended the peerless because your heat loss is 30k and you have 50 k of baseboard. Dont know why you want a boiler to heat 180f... The victory needs a condensate pump too.. Also I see it does not have the hydrostat control. Infact I see nothing that makes it DOE compliant... Unless it does not have to because of the efficiency...

Anyway the AL 29... Your going up the chimney right? 30 ft? Where you running the PVC for the inlet? Dont know if you can run them both up.... I briefed through the PDF but that boiler is not my cup of tee...Seen enough of them doing service work.

I would just go atmospheric then...

Oh lord time for bed.....

#188
04-12-13, 05:56 AM
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lawrosa,

i remember a document from weil mclain strongly recommending p/s piping for GV90+. the install pdf however says it's ok to pipe it directly for finned baseboard applications though. i'm not sure if IHW could be piped directly as another zone. the manual doesn't have flow/head tables for the boiler. so s/p might be needed for that application.

victory doesn't need a condensate pump since it's not condensing. the residual condensate from the exhaust pipe will evaporate before it can fill any container according to the slant/fin rep.

as i expressed in this and other threads, i'm ok with 180F. the benefits of condensing and running lower temp are well known, but i don't feel they are significant and outweight complexity and possibly lack of longevity. i pay about \$100-130 per month for heating with an atmospheric 2x oversized boiler that runs about 75% efficiency. going 2x as small boiler with direct vent and higher efficiency would reduce my bill even more. so marginal gain in efficiency due to lower system temp/condensing will be literary a dollar or two per month.

matter of fact i'm very happy with my current boiler, except it doesn't allow me to tighten my house a bit more since my draft is weak as it is all ready. but i'm still keeping it as long as it chugs alone.

i like the idea of cast iron boiler. with life time prorated after 10 years warranty on exchanger. the simplicity of the system and robustness of conventional boiler are really appealing to me. i feel like with victory i will simply replace my old boiler with a newer direct combustion one, but otherwise they would be very much the same. and since i'm happy with my current system, it would be a good but very invasive upgrade.

however if you say that victory doesn't seem to be reliable i would take that into account. if you can share some details about what kind of problems victories have, i'd appreciate it. as always, i'm not arguing with you, i'm learning

i could run intake/exhaust pipes thru the wall into garage and then about 20 feet up thru the roof.

i will take another look at GV again, even though it's a bit too big. but if it requires p/s for IHW, i will go with pf50.

12:45 am is definitely time for bed

#189
04-12-13, 06:21 AM
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lawrosa,

there is a specific length requirement for zone length when piping directly to GV90+ without p/s and i don't meet that requirement, my zones are longer. meaning i would have to go p/s with GV90+.

#190
04-12-13, 06:43 AM
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Here read this... I was poking around some. Interesting article.

http://www.blesi-evans.com/Sealed%20Combustion.pdf

All and all I strongly believe your draft issue is related to something else. This I dont think we touched on, or cant remeber the size of the current flue. The boiler may just be dirty is all. Could be lots of things.

If I remember from the pic of your boiler, its in the basement with plenty of cubic ft of space. I would probably re-think the whole sealed combustion.

If your that concerned you can have a blower door test done of the home to see how well its sealed. I had that done a few years ago, and it helped find key areas but IMO you can never seal the house to perfection.

Additionally if not an atmospheric choice is on the shorts list, and I can say your list is short , then consider just an induced draft. But I am not even sure the indiced drafts all pipe with AL 29.

But anything with a blower, has different controls that go bad IMO. Especially the electronics in a mod con..

Yes if you look at your return on a mod con investment in your case its a waste of money. As well as my case. I think we discussed already my gas bill is \$936 a year. My heat loss is 27K and I have a 85k input boiler that probably equates to 70k DOE. 43k oversized for the home.

I would rather see you go up the chimney with the vent then in the garage. Or follow the instructions for side wall venting for the commonwealth of MA. Its in every instruction manual.

AL 29 pipe is like \$35 a ft no? I say you have like 30 ft so thats about \$1000....

Anyway...... Dont want to beat a dead horse.........LOL

#191
04-12-13, 07:30 AM
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i got the point with a dead horse

5' z-vent al29-4c pipe comes out at about \$12 per foot:

http://www.prowaterheatersupply.com/..._store=default

going to the side wall would be less than 15 ft for me and it would have fewer elbows, mostly straight run.

i think during a slow season (summer) i could try to be proactive and get a quote for pf50 bases system and victory vsph60 base systems.

#192
04-12-13, 07:45 AM
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Yeah as far as the al 29 type units I have seen in the field most , if not all, were corroded to high he55!!!

Lack of maintainance, bad installation??? I could not tell you. The vsph does show a condensate loop on the blower so yes a pump would be needed. Dont know what the tech told you that it will evaporate.

The GV is the same size as the VSPH from what I saw....

I will really throw you for a loop if I suggest an electric boiler........ hey no venting issues and 100% efficient. Ha ha

#193
04-12-13, 07:56 AM
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I know your going to look at this.......LOL

http://www.slantfin.com/images/stori...tron_eh_10.pdf

#194
04-12-13, 08:00 AM
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if i go electric, i would go electric baseboards, that would be even more efficient! matter of fact i already have them in the basement, but we never use it. if electricity was cheaper that NG, it would make sense. 100% efficient as you said, simple, reliable.

gv90+3 is 70k input, victory is 60k input, pf-50 is 50k input.

it wasn't a tech, it was a rep from the slant/fin. he basically said that it's not a mod/con boiler so the condensate is only from the vent pipe and not even close to any amount that a mod/con would produce. he said that if collected in any container it would evaporate faster than it had a change to accumulate to any amount. his words, not mine.

#195
04-12-13, 08:06 AM
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I know your going to look at this.......LOL

http://www.slantfin.com/images/stori...tron_eh_10.pdf
very quick and dirty calculations show that if it runs less then 3 cumulative hours a day the cost is comparable with what i pay for NG now.

but i feel it would have to run longer to keep the house warm. i wonder what typical run hours are for electric heater.

i would imagine one would only want this for existing systems where one replaces a gas/oil boiler with electric. still i would rip off the fin baseboards and put electric baseboards instead of getting electric boiler.

#196
04-30-13, 07:49 PM
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piggyback

Hey all, great lots of information in this thread. @_Diver was Kind enough to point me towards this thread after answering a few questions I had on my own (seen here)"http://www.doityourself.com/forum/boilers-home-heating-steam-hot-water-systems/494189-advice-new-heating-system-dhw-gas-supply-relocation.html

I hope no one minds, but I figured it couldn't hurt to source a few more knowledgeable forum members that might be able to help me in my dilemma. If anyone would like to take a peek and maybe help a desperate new home owner out, I would really appreciate it. Thanks in advance

#197
04-30-13, 08:15 PM
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The one problem with electric BB.. they are not comfortable.
It's a terrible dry heat.

At least with an electric boiler, it will stage the elements as needed.
It stores energy in the water, and you can run ODR with it for a better more even heat.

Economy is one thing, but we don't live in caves for a reason. Take a look at air quality and comfort, not just plain cost of install or operation.

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