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Two quotes for combi boilers for radiant and DHW
Comments
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An epoxy liner an option?0
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I have a question about the approximate BTU usage for the radiant I should expect with a new combi boiler in the winter:
I should note that the radiant pipes are not in the kitchen, garage, or one of the bathrooms, so it's probably only around 1000 square feet. Last night it got to around 39 degrees at the coldest. I turned on the heat yesterday around 5pm and set the thermostat to 68. When I measured the interior temperature this morning it was around 66 or 67. With my 1947 era Hotsream 192-L (rated at 75,000 BTUs), over 17 hours I measured 8.5 therms of usage, or 1/2 therm per hour. It seems to cycle between being on for 11 minutes, off for 4 minutes, on for 11 minutes, etc, so I'm guessing it uses about .66 therms per hour when actually fired up, but the usage ends up being closer to .5 therms per hour because it periodically cycles off for a bit (when water temp gets high enough?).
So I'm guessing if my system isn't capable of reaching the desired thermostat temp it will end up using about 12 therms per day.
Given this, how many BTUs or therms would you expect in usage if I replace all that equipment with a new combi boiler? Would the combi boiler also be running 63% of the time (~15 hours per day) like my current boiler or would it be a lot less?
I realize it might not be possible to precise with my info above, I'm just wondering what the rough estimate would be.0 -
Is the home comfortable everywhere if there is no heat in two rooms? Has a loop or two been disconnected? Seems odd that someone would skip two rooms, unless they are an addition?
If two rooms are un-heated, or loops abandon, that would make me think more about plan B. Abandon the radiant and look at panel rads, radiant walls or ceilings.
Or with such a small load maybe mini splits make more sense. Heat, cool, dehumidify with that option. Skip a new boiler altogether. In your climate I suspect they run fairly efficient.
It is really the quality of the home construction and insulation that will dictate how much energy you use to heat it regardless of the system. Radiant, forced air, mini splits, electric baseboard, etc. It takes X amount of heat input. Then it comes down to the cost of the fuel. Electricity or NG.
I'd wonder if the slab had any insulation installed below. Or around the edge, that is a big heatloss area. If not it could end up being the most expensive system to run if a % of the heat just goes down into the earth, or out around the edge of the slab.
I would certainly look at any incentive for energy upgrades or dual fuel options, heat pumps, etc. In that ara there may well be electrification incentives. A heat pump could be the best, least expensive option. For both installation and operating cost.
www.dsireusa.org is a good place to start.Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
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Uggg... my question disappeared after I did a minor edit.
The bathroom with no radiant is an addition from around 1970. It has an electric heater in the wall. I'm not 100% the kitchen doesn't have radiant but I haven't felt it. it was remodeled in the 1990s and perhaps the thick tiles don't transmit heat. The garage has never had radiant.
The house is definitely a bit cooler in the areas with no radiant but it's not a huge difference. If I leave the heat i find it comfortable, and I certainly appreciate radiant heat.
The house does hold heat pretty well (dual pane windows, blow in insulation in exterior walls, and insulation above ceiling. I don't believe there's any insulation in around the foundation. You can see exposed cement around the perimeter of the house at the base.
I did get a quote on a mini split system that came out to about 1.7x the cost of all new boiler room equipment.0 -
Just a note on system leaks in these old copper tube systems. I've serviced and repaired at least a handful or these over my past 40+ years and typically found the leak near the toilet flange. If not a toilet flange it was a wayward remodeler who cut up the floor to move plumbing for a new toilet remodel and discovered the floor was heated. Small wonder! It's not too hard to carefully hammer drill up the concrete around an old flange, carefully update the flange if needed, clean the old copper tube, and sweat solder adapters to finish the repair with PEX. I've never had to abandon one yet.
I did have an early Polybutylene tube radiant floor leak from a home built back in the 70's that I could not locate. On that one I used a solution called Loop Conditioner. It's a liquid, similar to a boiler leak treatment that when circulated will seek out small seeps and seal them. I find it is used for sealing hot tub, swimming pools, and geothermal loop leaks that are too small to easily locate yet need frequent addition of fluid to help maintain pressure. It might be an alternative on older systems where repair is difficult.
https://geothermalsupply.com/product/geo-loop-conditioner-bottle/
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Here's a new problem that was just pointed out to me. The hot and cold water lines as well as the gas lines that come down from the attic are all in the way of mounting a combi boiler on the back wall. And the back wall is the only logical location for it because there wouldn't be room to service it otherwise. So all three of those galvanized (?) pipe lines need to be moved to the sides? I'm surprised nobody else that came out to look has brought this up..
This image shows some of it. Yellow boxes show water lines and red box shows gas line (left water line is obscured but I show approximate location):
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Its really not that hard for a plumber to reroute those pipes as needed. Cut them near the ceiling and offset them as need
it looks like a lot of piping cleanup needs to be done. I suspect the bids you received took that into account
the finished project should look like the pics I attached a few posts upBob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream1 -
Do you feel that the NTI FTVN150C would be a better choice than the VIESMANN B1KE-120?
The NTI is a bit cheaper, but my primary concern is how well it will function for my needs, reliability, and hopefully reduced maintenance costs.
I really appreciate all your advice @hot_rod0 -
Alan, a local eluded to the fact that one of those brands has better parts availability and support in your area
all brands can breakdown, being able to get parts can be an important part of your decision
It can take a week or more to ship across the country these days.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
Kind of makes you wonder where the installer is getting the boiler if there aren't parts available locally.0
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V. and NTI boilers are stocked locally, but the wholesaler doesn't carry a lot of parts. So, I carry V. igniters, flame probes and burner insulation for most boilers on my truck. Same with Munchkin and some TT.
I carry no parts for Lochinvar and seldom need parts. That's how good they are.8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab0 -
@Alan (California Radiant) Forbes
Wow, you are doing the distributors job for them, those manufacturers ought to send you a nice christmas gift as you have no doubt prevented many very angry phone calls. I try to keep basically everything but the heat exchanger, and casing on the shelf, I just couldn't live with myself if I was selling equipment without keeping parts on hand.
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We did a job in a small space like yours in Novato. The V. boiler had sooted up and was spewing carbon monoxide and we installed a Lochinvar heating only boiler in its place. Above it was a shelf with an on-demand heater for the DHW. Broke all the rules.
8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab
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Impressive fit Alan!
I do have 30.5" of width in my closet so a little more room than in the photos above
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Yes, but on this job we had the advantage of being able to remove the left wall to do the piping.You can also install an on-demand water heater on the outside of the house. Less clutter in the closet. Easier to service.8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab0 -
I assume it would be sensible to pay a bit extra to have the tie-in point of the new equipment not be right above the red circles, but instead to have new copper headers/valves installed at the same time? (ie everything in the red circles is replaced as well). That would push it to all copper I think.
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Hard to tell for sure, it looks like two of those valves are shut off, judging by the exposed stem. The green handled one looks like a different brand or style, that could be the reason for the difference?
Maybe consider paying Alan for a system inspection at the very least. Write up a scope of work so everyone is bidding on the same fix.
Experienced Eyes on the ground is what you need. Do more homework before you start determine the replacement boiler brand.
Certainly I would start with new balance/ purge valves on the 3 zones. There is not much in that picture that I would try to salvage.
Make sure the bidders spell out exactly what you are getting in the rebuild.Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
Thanks. I'm trying to prepare myself as much as I can from this thread and I understand where you're coming from. One of the aspects I've been asking for in the bids is to replace everything, so I just wanted to make sure that was sensible. The second bid in my initial post didn't include the those headers/valves and I had asked them to include it. I still need to confirm that the IBC boiler bid includes it.hot_rod said:Hard to tell for sure, it looks like two of those valves are shut off, judging by the exposed stem. The green handled one looks like a different brand or style, that could be the reason for the difference?
Maybe consider paying Alan for a system inspection at the very least. Write up a scope of work so everyone is bidding on the same fix.
Experienced Eyes on the ground is what you need. Do more homework before you start determine the replacement boiler brand.
Certainly I would start with new balance/ purge valves on the 3 zones. There is not much in that picture that I would try to salvage.
Make sure the bidders spell out exactly what you are getting in the rebuild.
I'm pretty sure all the zones are open and I can report that after leaving the system running for 24 hours the house was quite warm, and has remained comfortable over 24 hours after shutting it off.
I'm taking a bit of an incremental approach here where I'm getting a few bids and then asking a lot of questions hoping to eventually end up with a decision that makes the most sense. Given how well the system seems to working at the moment I am inclined to pursue updating the equipment as opposed to going the mini split route.0 -
I'm pretty sure I'm outside of his service area. He did suggest some places I could contact, though.hot_rod said:...
Maybe consider paying Alan for a system inspection at the very least.
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Would something like the CX 150 make sense in my situation? I am bothered by the idea of the SFC's aluminum all-in-one heat exchanger based on what I've read....
I like IBC, but only the ones with a fire tube heat exchanger - model CX combi. The SFC's have a Labryinth heat exchanger, not my fav. Parts are stocked at a supplier in Richmond; always a good selling point.
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I'm trying to compare the CX specs...
(https://www.ibcboiler.com/consumer/products/cx-series/cx-combi/)
(https://www.ibcboiler.com/consumer/products/sfc/sfc-199/)
CX 150 vs SFC 199
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CSA Input (Nat. Gas or Propane) – MBH: 15-150 vs 28.3–125
Domestic hot water delivery: @70°F/ 39°C temp. rise: ???? vs 5.0 GPM
Min. Boiler Flow Rate - US gpm: 3 vs 2
The input range looks much better / more versatile.
Not sure exactly what I should be looking at here or what a lot of the specs mean. Why is there no equivalent spec listed for the CX 150's DHW delivery? How does a min flow rate work if you're demanding less than the minimum flow?
I'm partly pursuing IBC as an option because, despite having contacted about 9 places there are only 2 at this point that seem like they want the job and that I feel would do good work. The IBC place in particular looks like they'd do a particularly good with the install. I'm fairly certain they only install IBC combi units, though not sure which ones.
Here's a photo they sent of a before/after that pretty closely matches my situation:
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For the sake of completeness, here are a couple photos of installs done by the second place I'm considering. This is the place that gave me the bid for the Viesmann but also offers the NTI as an alternative:
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The brand of the boiler doesn’t have much to do with the DHW production. It’s the boilers btu output size, that you look at.
That IBC shows 138,000 actual output.
The formula I showed earlier still applies.
500 x flow rate x temperature difference
500 x 4 gpm x 70 rise = 140,000btu needed to raise 4 gallon per minute 70 degrees. So just under 4 gpm with 130,000 available from the IBC
Again, if you don’t need or want a 70 degree lift, change that number
Say your water is 55 incoming, and 110 is plenty hot for a shower, and all the hot water needs, then you use a 55 degree lift
500 x 5 gpm x 55 degree rise= 137,500 btu, so the IBC or any 138,000 output boiler would give you about 5 gpm.
Although unless you have a fast fill tub valve I don’t know why you would ever need 5 gpm of constant DHW?
Make it even simpler with this rule of thumb every 50,000 btu of boiler output will get you just about. 1.5 gpm of dhw at a 70 degree rise.
A 100,000 boiler output= 3 gpm
A 150,000 boiler output = 4.5 gpm
That 138,000 IBC= a bit under 4 gpm
If or when you incoming city water warms above 55 degrees your gpm available goes up
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream1 -
In case it wasn't clear, I'm wondering about the comparison of the IBC SFC 199 vs IBC CX 150. More specifically, whether the CX might be a better choice for my needs given the concerns regarding the SFC heat exchanger as well the fact that the SFC 199 seems oversized for the radiant needs. I'm not too concerned about hot water production, though I was curious about the significance of a higher minimum.
I'm also curious about thoughts on the installs, given the photos. The added wood paneling, labeling, isulation, etc of my first example certainly seem like nice attention to detail. Also, could help with noise isolation.0 -
I would not go over a 150,000 for your application. With 3 -1/2" loops, even a 110 would be plenty.
But you do need to keep DHW in mind with a combi.
While a 110, 000 would be plenty for the house, DHW is down around 2 gpm. I'd bet a 55,000 boiler would heat that home actually.
The room is not in too bad of shape.
If the water heater is leaving, remove and cap off that large flue pipe at the ceiling. It will just pull heat out of the room/ boiler.
That opening for the boiler should really be capped off if you are still running the water heater?
On this list you will find folks that love and hate pretty much any boiler brand or model you bring to the table Every installer has favorites, and brands that they will never touch. Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
That isn't my room. It's just the "before" shot of another room that the IBC installer shared with me. The shot of my room is in my first post in this thread. The work I'm considering is basically removing everything in my closet (radiant boiler, water heater, most of the piping) and replacing it with a combi boiler setup.hot_rod said:...
The room is not in too bad of shape.
If the water heater is leaving, remove and cap off that large flue pipe at the ceiling. It will just pull heat out of the room/ boiler.
That opening for the boiler should really be capped off if you are still running the water heater?0 -
This is or isn't your mechanical room? It is the pic in the first post? And the pic a few posts up.
If so it looks like the flue from the boiler gas been disconnected in the recent picBob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
They're two different roomshot_rod said:This is or isn't your mechanical room? It is the pic in the first post? And the pic a few posts up.
If so it looks like the flue from the boiler gas been disconnected in the recent pic
The picture in my first post is my room. The other picture was a "before" picture that the IBC installer sent me because that job closely matched what my room looked like. My boiler and water heater fill more of the space than the "before" picture room.0 -
I was hoping the flue is still connected if you are still running that closet bomb
Must have been the same installer.Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
Yeah, I'm guessing that was a setup that had been abandoned prior to the install of new equipment.hot_rod said:I was hoping the flue is still connected if you are still running that closet bomb
Must have been the same installer.0 -
@ThinkpadUser7 said:I'm not too concerned about hot water production, though I was curious about the significance of a higher minimum.The IBC CX combi and the Lochinvar Noble combi (floor or wall mounted) would be good choices. Either their small or midsize models would suit your needs. The midsize gives you more DHW and would modulate down comfortably.
I'd go with either installer as their work looks clean. Make sure they follow the manufacturer's instructions and insulate their pipes.8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab1 -
@kcopp brought up an interesting point in a private message:
For the closet IBC install example ( https://us.v-cdn.net/5021738/uploads/editor/fl/znu7gy7yng88.jpg ), is there really enough combustion air available with the interior intake?
I do have openings in my exterior closet door: https://us.v-cdn.net/5021738/uploads/editor/cj/o4tqlld10u2p.jpg
But would it be much better for the health of the system to ensure that the intake is routed to an exterior location?
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Centrotherm vent has a kit that uses that old flue pipe for exhaust and intake air from the roof
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
The viessmann installer shows an install where they are pulling combustion air from the small room with an atmospheric vented water heater, very dangerous. I would say go with the IBC installer all day,0
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@GGross Good call - and no neutralizer on the condensate.8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab0 -
Maybe that small room has no door and perhaps is even open to the outside?
Also, how can you tell there's no neutralizer? I'm trying to figure out where to look...
FWIW, the Viesmann installer specifically mentioned this the bid:
"Install Condensate Drain with condensate neutralizer to floor drain/side yard"
I see no mention of a neutralizer in the IBC bid. I'll need to ask about it.0 -
Here are couple more example installs from the IBC installer that show more:
And here's one more example from the Viesmann installer:
Any other conclusions or insights @Alan (California Radiant) Forbes @GGross ?
(or anyone else 0 -
Personally I just can't un-see that venting issue I mentioned, it's egregious imo. You could ask the IBC installer if they could also include a condensate neutralizer in their quote. It seems like such an obvious thing to do, but condensate neutralizer usage seems to vary regionally. In my area for example they aren't required so almost nobody installs them, this will come back to haunt us some day though0
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If the condensate drains outside to a soak away drain or pit, no need for a neutralizer. Although I'm not sure if draining to the ground is code compliant?
The second pic has some sort of filter on the HW piping? Maybe protects the reirc pump.
Hard to tell the piping, all the insulation blends together.
If the room has no door, or vents in the door, that would be acceptable for combustion air. It's the same outside air either way.
A very nice insulation detail, great workmanship and component selection, lots of labels. Possibly a system documentation left behind? I like the large pressure gauge also.Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
hot_rod said:
The second pic has some sort of filter on the HW piping? Maybe protects the reirc pump.0 -
The SFC need BOTH the intake and the exhaust piped to the outside. There are NO exceptions. page 1-15 of the install manual.
The installer did very clean work but neglected in those pix to have that intake run outside....0
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