Help finding the right hydronic boiler/heat source

tbrooks

I could prob swing that eft combi unit. Its a little pricey, and will put me over my planned budget. An eft 55 would modulate much lower, but I would have to do something for dhw. Probably could pick up a cheap tankless for domestic, but thats gonna reduce efficiency. The brochure shows it with an indirect tank, but to me that doesn't seem any better than a tank wh. I'm gonna keep searching and see what else I can find

Rich_49

Hat ,

Let him know what he can expect from the old style tank water heater using it for both DHW and space heat .
The EFTC does come in 2 versions . The wall unit does not have the 15 gallon DHW buffer and costs less than the floor model with the buffer for DHW .

Rich_49

There ya go ! In a couple years when your daughters want or need something by spending a bit now you will save alot every month .
Look up possible utility incentives and programs for your state

http://programs.dsireusa.org/system/program?state=NC

You can probably save enough money to make the house a little tighter as time goes on , lowering your consumption further . You are only looking at first cost and forgetting the real important math . If you spend 2,000.00 less now but it costs you 125.00 per month to operate as opposed to 50.00 a month for 10 years , the math speaks clearly .

3,000.00 bucks now probably pays for itself in 1 year 1 month as opposed to saving 1,000 and giving the utility that extra 75.00 . Of course I used a number that is typical in my area for a family of your size using 1 appliance for DHW and Space heating . Here is the problem , many researching these types of systems tend to care more about the investment and listen to the guy who has the system you are describing who are happy they are warm and their gas bills are 2/3 less than if they had complete garbage and think they can buy something else for their home . The guy that spent the added monies on a bit of technology who is saving that 75.00 per month is often discounted , maybe he uses a piece of plywood and formica for a year and a half then gets the granite with the cast iron farm sink . At least he has an extra 900.00 per year to buy those little things he wants or that his family needs .

Spending a little money to upgrade the LARGEST gas consuming monsters in your house is always smart .

jonny88

Hat I didnt realize a combi needed 25 mins recovery time between showers.Am i missing something here which is always possible with me....I was under the assumption they would give continual flow at a fixed gpm.Not a fan of combis though.

RobG

A combi is essentially a boiler with a built in flat plate heat exchanger. You can run it all day and never run out of hot water.
We don't discuss pricing here but this is a cost example: http://www.ebay.com/itm/like/181735436543?lpid=82&chn=ps

It will do both the domestic and space heat. If you wanted you could use the LP water heater as a buffer tank.

hot_rod

My experience with Combis is you need at least 130K input. I tried a 110K Combi on my own home, and it struggles to keep up with even a tub filler. My in laws have a 130K, been working for 6 years now and it performs fine.

As mentioned altitude, incoming water temperature, flow rates, and maintenance all factor into actual performance.

The main issue with tankless or Combis is that they are not explained and presented to the HO properly.

SWEI

Do the in-laws have the same incoming water temp as you do?

hot rod said:

The main issue with tankless or Combis is that they are not explained and presented to the HO properly.

^^^^THIS

tbrooks

Wow lots of responses, thanks everyone. As to hot water usage, we're used to a 30 min recovery time now, and all but one of my family takes ten minutes or less. The one seems to stay in til the hw runs out lol, we've been working on that. It would be nice if we could all get showers in a short period of time instead of spread out through the evening. Mainly for my 2 oldest to get theirs one after the other, so about 30 mins of hot water.

Rich, I understand what you are saying completely. I have to look at first cost though, as that is what I have to pay for all at once very soon. As I said though most of my house will be reclaimed, my counters will be concrete done by me with crushed Jager/wine bottle aggregate, and my kitchen sink will be an old double laundry tub that's been in my yard for 15 years. Hell, I'm building all my cabinets, furniture, doors, and 75% of my walls from reclaimed wood. That I am reclaiming at no cost to me other than time. I have no corners I can cut to come up with extra cash for something like this. Except for the floors, but between this heat and a toddler, I can't really wait on getting the floors finished. I'm trading my chrysler 300 for a 91 mazda to be able to afford this. Hopefully I can make a few k from the estate sale, and other things I don't need, but I can't be sure or dependent on that. Its very hard to do all this on a little better than paycheck to paycheck budget with 3 kids. Its taken 3 years just to save up what I've got. Honestly I can't afford all of what needs to be done, but I need/have to for me and my family, and know I can get it done and make it work. The thing is by the time I'm ready to install the system, I'll know what I can spend, but I'm trying to get everything planned now, while I have time to do research.

Anyway enough about me being poor, as I said I think I could swing that eft combi. My thought on the eft 55, is that it would be more effiecient for my heating, and save much more money long term, since it modulates 10000btu/hr lower than the combi. Considering my total highest heat loss will only be 18000btu/hr, and the fact that 2 of my bedrooms will only be occupied half of the winter, I will be running at a fraction of capacity most of the time. but again the problem then is dhw. The 55's top btu with indirect dhw probably would be worse than a tanked heater for domestic. There is probably no way I could heat the water and have the combined efficiency of the combi.

My biggest problem is knowledge. I read johns book and have been pouring over all this info for weeks, but there is just to much info. I don't know or understand near as much as you guys, and I want this efficient as possible, but as cheap as possible. I know they don't go hand in hand. Most importantly I want it done right, not just thrown together and oversized.

If I did go with the combi wall mount would it be feasible to use a water heater for a buffer tank? Just a thought, that could save me alot of money. There is a small electric one at the house now, and of course the lp one I have, but it is kinda large.

tbrooks

Oh and also, what about the pump curve with a variable speed pump? Anything I find is gonna be oversized. Should actually draw out a system curve to compare to the pump curve to select my pump, or will it be fine as long as my top head and gpm fall within the variable speed range?

hot_rod

What is the pump spec? There are some micro pumps available, but I have only seen the Euro versions in 230V.

The B&G Vario gets down pretty low.

tbrooks

I haven't seen that pump before. It's so hard just to find products for radiant, I've mainly been looking at supply house, because they have a large variety. I've been looking at the grundfos 15-42f/vs. It is kinda pricey, but goes very low as well

Paul48

Rich....I guess the Contender has been discontinued? The MC50 is still around and cheap. That would leave some room for an indirect. Just thinkin out loud.

Rich_49

Maybe this works and meets TBrooks needs .

Phoenix Light Duty
http://www.htproducts.com/literature/Phoenix-LD-Brochure.pdf

FPHX for space heat . See attachment . smallest FPHX will do .

Taco 1816 on min speed for water heater side of flat plate .
http://www.taco-hvac.com/products/water_circulation_pumps__circulators/variable_speed_products/viridian_family/index.html . See instruction sheet . I'll let others recommend system side pump because we all know I'm gonna say VT2218 .

Taco 5000 mixing valve or Caleffi equivalent . For domestic .

Zone relay able to power both circs during space heating call .

Store in the heater at 160* . Mix down for the DHW , tell your wife 110* water is what she will have to live with . Everyone else should be able to shower just fine and the kid that runs it out , tell them good luck now . In summer put the thing on Eco mode , this will derate the burner by 20% . Zone the whole thing independently room by room and do not worry about the SWT because as I always say , when the surface temp reaches what it needs to be the T stat will close that zone . No more flow , no more heat .

Well , that's what I got for a damn good system on a budget . Hope it helps you .
You can call me and I will have the stuff shipped to you for my price . You just arrange payment and tell the supplier where to ship . This should get you in the price range you stated .
Paul48 , there may be a few of them still floating around but that will be it , they are gone also , the MCs that is . I think this is a real good option . Kinda like a versa hydro on a budget .

tbrooks

Thanks Rich. So it sounds like dhw with indirect floor heat system? Sounds like a neat and logical idea. I'm not sure if it will end up being cheaper or more efficient than the eft combi though. Part of the problem with looking at these htp products is finding pricing for them, its not so easy. Looks like the phoenix with the added parts, will be about the same as the eft combi. I appreciate your offer to help me obtain everything as well. I think for my planning stage I'm at a pretty good stopping point. It seems whichever route I choose I am going to need to build a small lean-to on the house. These units need quite a bit of service clearance and they are not gonna fit in my crawlspace or a closet. I'm still gonna plan on putting my manifolds under the house in a central location, for better distribution. So from here, I'm gonna draw up my piping layout, but otherwise I think I have enough info to proceed, and make a final decision when I know how much money I actually have.

Rich_49

Will be only slightly higher than EFT combi . However , you will not have to buy separator and a few other parts that would be necessary either making it more affordable . remember also , you have the ability to have this stuff shipped direct at my cost .
HTP products are nit hard to find pricing for , They just don't sell through every Tom , **** and Harry internet vendor , this is not a bad thing . You go ahead and search the internet for pricing and I will put together a list of the parts and e mail them to you . Please forward your e mail address as I don't want to attempt to PM you on here and them end up posted .
This is a little more than half the BTU of the combi and in summer you can throw it into Eco mode . Like I said , it's a poor man's Versa Hydro we're building here .

tbrooks

Thanks Rich. I sure appreciate all your help, patience, and understanding for diy/newb like me. As I said I will hold off for now until I get my major costs out of the way, and know exactly how much money I can spend, hopefully I can afford something better, but what you have outlined sounds pretty good. Just the heat transfer plates on this system with 1900ft of pipe, is gonna be a small fortune!

Rich_49

Whose heat transfer plates and tubing are you planning to purchase and use ?

tbrooks

Honestly I haven't put much thought into it yet. I was planning on using pex, but I've looked some at transfer plates and not sure how much money I want to put into them. There are some cheap ones and some expensive ones, which I know there are difference between plates and types/ways of manufacturing, but not sure how much difference they will truly make

SWEI

Research shows that properly installed extruded plates will increase your heat transfer roughly 175%.

tbrooks

SWEI said:

Research shows that properly installed extruded plates will increase your heat transfer roughly 175%.

Is that in comparison to no plates or to the cheaper stamped plates.

SWEI

That would be to no plates. Can't seem to find the link to the ASHRAE project Sigenthaler alluded to in "Plateless in Radiantville" but reading it pretty much settled the argument for me.

tbrooks

Seems like I remember seeing that somewhere. In his book he mentions extruded and graphite, and shows a thermal image of both in use. The graphite looked like it distibuted the heat better. But I also saw another study showing a few types of extruded compared with graphite, and the graphite did horrible, but this study just had the plates in open air

tbrooks

static1.squarespace.com/static/50de4c94e4b0a05702aac0fb/t/511a6e48e4b0735b6626ef38/1360686664633/PlatelessInRadiantville.pdf

tbrooks

That is just more talk of plateless, as well as his article "Shakeout Time". I had already decided from reading his book that plateless was definitely not an option, no matter how much money it saved me. I also discovered this
healthyheating.com/thin-plate-versus-thick-plate.htm#.VU9Ar_lVikq but that is kind of a biased comparison, as different width plates are used. From the heat imaging picture, i would tend to think the wider, thinner plate does a pretty good job, and if they had used the same size plates, the results would be much more similar. I personally can't get the thought out of my head that the "c" plates leave exposed pipe, that would cause more heat loss.

Rich_49

Although it may seem that the C pates leave more exposed pipe , it just is not so . The extruded C plates have FULL contact with the pipe where in contact with the pipe . It would take someone painstaking attention to achieve a similar amount of contact with anything other than extruded plates . In my opinion , the same amount of contact cannot be made with stamped plates .
Contact with the floor is the second issue and the best sub floor to plate contact I have witnessed in an impressive looking job was quite probably less than 60% contact .
Don't misinterpret that hump in the graph . We would call that responsiveness and this is not a bad thing . The C plates are unloading BTUs faster into the floor .

tbrooks

I understand what you mean there. The heat is transferred through conduction, so therefore, better and more contact is more heat transferred. With this faster transfer, would there be any concern of short cycling? I know that it would create a better deltaT and therefore increase boiler efficiency. I'm gonna keep searching and hope to find a study with better comparison.

tbrooks

Found this statement on another site
"Our data suggests that the options of no aluminum plates at all, heavy duty aluminum plates, and aluminum foil can generally be ruled out. The real decision is between a continuous covering of the tubing with a medium/light gauge aluminum stock, or an intermittent covering of half of the tubing. We have arrived at the following recommendations:

If heat loss downward (backloss) is entirely wasted as to a crawl space or basement, cover the tubes entirely and insulate well. If heat loss downward is useful to another space, then a reduction in aluminum by half should be considered.
If the flooring material is thick or carpeted, the tubing should be covered entirely.
If low operating temperatures are desired, as for solar heating applications or for very high efficiency, or for other reasons, cover the tubing entirely."

Rich_49

Could you provide a link to this study Brooks ? Half the coverage in an attempt to heat a lower and upper space simultaneous;ly is a JUNK study .
You may do best by discontinuing research and start shopping . The system is as inexpensive as you are going to get it , any further savings with the exception of someone donating material will hurt the system you are planning .

RobG

What Rich said. And if you want to hear that your heating system is running, use the stamped plates. They will ping and pop all night. You really only want to do this once. Do it right.

tbrooks

That last bit came from here radiantec.com/pricing/heat_transfer_plates.php
Not really a study, just a statement from a 36 yr old business. I just want to know how much of a difference there is between extruded and stamped. But after reading on that site and thinking about the fact that they are much thinner, they will tend to move more a Rob said. I've got a few months so maybe I can grab some cheap here and there of ebay, if people over order and sell the extra lol. I will need to get my drawing done as well so I know exactly how much of my pipe will truly get the plates. In underfloor are the curved ends usually left bare? I would at the least run some flashing as a reflective surface, I think.

RobG

Yes the return bends are left bare as that is where the expansion of the PEX will end up. Just make sure that you insulate the edge bands very well to keep the heat inside.

tbrooks

By edge bands, I think you mean the band boards on the floor framing. That would make sense, I could slap some flashing on the new ones before I put em in, just to help reflect some and then add some blueboard before I put the subfloor.

All ebay currently has is mainly the "omega" style stamped plates. I guess they would be kinda inbetween the quality of stamped and extruded, but they are at the stamped style pricing.

tbrooks

Oh and rich I won't be shopping for a little while, unless I find some really good deals. I've got about 3-4 months, before I'll be far enough to know exactly what I can spend. Found a dhw boiler on cl that had an output of 110* at 2gpm lol, good luck to whoever gets that.

SWEI

http://radiantengineering.com/theheatexchanger/2013/3/4/comparative-infra-red-study-of-heat-transfer-plates

Rich_49

Please do yourself a favor and stay off that site . 36 years or not , these guys are terrible and have no issue selling their wares and leaving you for dead when you need them

Rich_49

Too bad Dale is such a cantankerous old fart SWEI . He does make some nice stuff .

tbrooks

SWEI said:

http://radiantengineering.com/theheatexchanger/2013/3/4/comparative-infra-red-study-of-heat-transfer-plates

That is one of the sites I visited, but first found it odd that they would do the test in open air, as thats not how these plates function. Second siggy talks about graphite plates in his book and shows an infared image with them installed beside extruded plates here:



Those results ^^^^ are opposite what that "test" shows. And 3rd that test is performed by a company making extruded plates. And 4th who's dale

SWEI

The image above was sourced from Watts Radiant, who sells the graphite plates in question. It was quite likely done using one of their larger diameter tubing products which would have much better graphite contact. That said, we achieved very good results using their FlexPlates on PEX for a retrofit project (fixing a bad staple-up job) where conditions made flexible plates the only real option.

Dale Pickard is one of the owners of Radiant Engineering, the inventors of the extruded plate.

More reading http://scholar.lib.vt.edu/theses/available/etd-01182006-011730/unrestricted/Performance_Test_Protocol_for_Radiant_Floor_Heating.pdf

tbrooks

Well I just kinda skimmed that and looked at the pics, cause I'm about to leave, but their floor temp results were almost exactly the same with or without plates