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Converting from oil to natural gas - Navien CH210 was recommended (34 Posts)
Converting from oil to natural gas - Navien CH210 was recommendedHi,
I've been reading here on the forum and have seen lots of useful info as we convert from oil fired hot water heating to natural gas fired. My background is just a do-it-yourself homeowner, and I know this project is beyond my abilities, but I like to be as informed as I can on major expenditures.
First, a bit about my house/system: 3 bedroom, 1 bath, 1953 ranch house, about 1300 sq. ft. I have efficient replacement windows all around and have sealed the house pretty tightly, and upgraded the attic insulation. The geographic area is upstate NY (Albany area). My current heating system is a 91,000 BTU oil fired HW boiler, 9 years old, with a tankless coil for DHW. The radiation is copper piping with baseboard radiators each consisting of 3 horizontal copper tubes with steel (?) fins.
I've been getting estimates on the job and one proposal is for a Navien CH210. It looks great in theory. I've been doing a lot of research on it and other models, but am not fully confident on this model's reliability and durability. I think that's my major concern, coming from a background of cast iron boilers that really don't need much in the way of maintenance other than cleaning and tune-up.
Has anyone got personal experience with the CH210? What sort of maintenance do combi boilers require? So far I have two estimates from different contractors (with other options included) and the prices are quite a bit different. Budget is an issue as I'm retired and I'm hoping to take advantage of the current double rebate offered by National Grid, and everyone I have talked to says their heating bill with the narutal gas is about half of what they paid for oil.
SearchGo to "search the wall" and read all about it.
The navien subject has been beat to death on here.
ch210I believe with Nat grid your double rebate is only if you use a Burnham boiler.anything else you will qualify for a EE rebate around 400$.
I have installed a few Naviens.They get mixed reviews.Boiler might be cheaper but installation cost is pretty much the same as with othe condensing boilers.Make sure you have a minimum of 7 inches wc on gas.use a spin down filter on water inlet,polypropylene on vent,and correct p/s pumping.Unit is only as good as the installation.good luck
HO1?I'm sure he has an opinion...Waiting for it for my response..As Carl has said, beating a dead horse.."The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."This post was edited by an admin on August 7, 2013 8:53 PM.
Just made a newbie mistakeOK, I just wrote a long post and lost if because I forgot to do the math problem before hitting "submit". Hope I can touch on my main points.....I had been hoping to learn of any newer or updated thoughts on the reliability and durability of the Navien and combi boilers in general.
I had done a google search and already seen many of the posts, but all the additional reading I did about the Navien and combi boilers in general seemed to confuse me more. It seems that the general consensus is that there is more maintenance required and replacement of condensing boilers can be expected every 10-12 years, and that's one thing I wanted to know.
The contractor who offered the Navien setup is the largest one in the area. The guy looked at my current boiler BTU rating, looked over the piping in the boiler area, did no heat loss calculation at all and spent maybe 5 minutes tops. Not what I would call real customer attention, although he offered to answer any questions I might have. Trouble was, I just didn't know the right questions to ask
The second contractor measured each radiator, did some calculations, looked over the boiler area, and offered several options for the switchover. He spent about 30 minutes with me. One option was a Bryant BWB cast iron boiler with a Bradford White Powervent gas water heater. (I already have a stainless steel lined chimney). All of the options he offered were considerably more costly than the Navien setup, and this combination would not be eligible for the Nat. Grid rebate. But I'm wondering if in the long run, with a longer life span, if I might still save substantially on my heating bill.
I guess my main goal here is to gain substantial savings by switching to the gas. I have detailed oil purchase records over the 9 year life of my current boiler, and am hoping to figure a general percentage of savings I might expect at current prices by even switching to even the 82% efficient natural gas setup. I also want to get away from my dependence on oil because who knows where the price might go, especially considering the volatility of the Middle East.
Hope I'm making sense here, it's been a long day!
Begin at the beginningSomeone MUST perform a building heat loss calculation. This should take into account existing and planned (near-term) envelope upgrades. It's best to do a full room-by-room heat loss, addressing any current imbalances in the system. Once this is done, it is combined with an estimate of domestic hot water demand and the two together will determine how much of what you need in order to make everyone happy.
Any contractor who does not perform a heat loss calculation should be shown the door.
LLContractor number 1 sounds like the wrong guy . Anyone who comes in and looks at current BTU and will do like for like should be thrown out and not considered . As for being the largest in the area , this is a phenomenon that is all too common . He is selling the cheapest stuff , making it look great , using manufacturer spoon fed nonsense and in 5 years everyone will be tearing out the stuff possibly as part of a Class Action . People like cheap stuff and contractors who sell cheap stuff get overwhelmed by work load and then quality suffers . There are 3 REALLY BIG companies like this in my area and I have to say thank you to them because when the market dropped out for new work I made quite a good living troubleshooting and fixing their installs . How come they could not diagnose basic heating system problems on their equipment ? Contractor 2 is a little better , he measured the existing radiation ,and did some calculations . Did he measure the rooms , windows , doors , exposed walls and ask about insulation R values ? If he did not measure the latter things discount him also . YOU must have a heat loos performed . I measure every house whether new or replacement , by the way so do most of the guys on here . Take our advice and let what the homeowners who have a 1 year old system where it has not been tested yet opininons go in and out your ears .
My thought is that you will end up with a space heating load of between 41,600 and 52,000 BTuh . This takes into account what you have said and a 4 - 5 BTU per cu. Ft requirement . Of course that is speculation but I would bet near correct .
Don't install 2 gas units , you will have a boiler , use it to make your hot water also . Since the appearance of mod cons and the like the good old cast iron boiler has been a stepchild , when in all reality a well installed and controlled CI boiler can actually outperform it's condensing cousin because more contractors than not don't make sure it condenses , lowering the efficiency to right around the AFUE of CI . Your DHW usage should also be taken into account . I would add that 41,600 & 52,000 are fine water heating numbers also . Store water in an indirect at 150 or 160 and use a mixing valve to temper down to 120 , you will have all the hot water that you need and the boiler will have plenty of time in all seasons to replenish before running short .
Good luck with your projectYou didn't get what you didn't pay for and it will never be what you thought it would
Don't beat me up because of this question! ;)Just a theoretical question...if the current system is adequate, and the efficiencies of the old and new systems are about the same, isn't it logical about sizing with the same BTU boiler? As mentioned, the current boiler has been perfectly satisfactory.
Thanks for the thoughts so far.
Don't Get Caught UpOn AFUE. It's a lie and only pertains to the boilers combustion efficiency. Has no bearing on system efficiency.
Here is why I would never, ever, ever choose either one of these guys. Because neither of them probably know that the max flow rate of the on board pump for the Navien will flow is 5gpm period! Without a heat loss and emitter calculation there just rolling the dice.."The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
SameBTU boiler . If it is satisfactory and adequate why rush to change it ? But since you ask here it is . Your first reason for changing boiler is Financial . So why put a larger boiler than you need that will cost more to operate than one of smaller adequate size . I have rarely come across a properly sized boiler , properly sized emitters , and hell seeing a properly sized boiler and emitters in the same place is like seeing a VelociRaptor in the woods in Antarctica . It's that rare or so it seems . So spend a little less on your first cost by investing in the less expensive , properly sized boiler , find a qualified designer / installer , have your new properly sized boiler installed to play nicely with your existing emitters and SAVE your money every month . Or Not .You didn't get what you didn't pay for and it will never be what you thought it would
NavienBlindly replacing a boiler with the same size is not a good practice.
I wouldn't expect every contractor to a thorough heat loss on the first visit. It should be done before the project begins. I would expect them to determine the size of the house, lineal footage of baseboard and ask some questions about your hot water needs.
If you are curious, measure all you heaters and multiply your total footage by 600. This will give you the maximum amount of BTU's your house could possibly need.
The Navien is a lesser product than other condensing boilers. It comes at a lesser price.
Not Need CarlThe maximum capable output it can produce. I would also use 560 or the 1gpm flow rate not the 4gpm flow rate of 590-600.. Not jumping, just sharing..
I'd be more concerned knowing that heat loss for my water temp and ODR calculation. ODR is an option with the Navien and the OP has never even mentioned that they offered it."The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
grrrStill getting used to this forum.....just tried to post a lengthy reply without a Post Title and lost everything again. Sure is quirky software.
Anyway, based on my continuing research, I've discarded the Navien idea. The condensing boilers just don't seem to have the track record and durability I'm looking for, so I am looking into a traditional cast iron gas boiler setup. Thing is, I have to be real careful on the budget, I'm retired, but not collecting SS yet, so things are a bit of a squeeze.
The second contractor has been very helpful and eager to answer any questions I've had, and has offered me more options than are in the original proposal. I'm trying to get an idea of which way would be better to go, fuel-wise: separate boiler & HW heater, or boiler & indirect HW heater. Currently, my oil boiler has a tankless coil, so I'm used to getting both off one unit...
Huh?Track Record and Reliability. Let's see, there are millions of condensing boilers sold across the world yearly. The entire US market accounts for about 300,000 boilers a year total in all make and kind. Viessmann as an example, produces 400,000 just in wall hung condensing boilers a year.
Don't know what is more reliable then a modulating condensing gas boiler with the same warranty as a cast iron boiler. Would love to know where your reading all this. Also remember this saying, "Its not the arrow it's the Indian."
Better off with an indirect. If you are going to cast iron I'd look at the Burnham Series 3 or ES2 and add the ODR card..Going to be pretty close to the condensing price point though.
warrantiesI have yet to come across a condensing boiler "that I can afford" with a 10 year warranty on parts and a 20 year warranty on the heat exchanger. Can you point me to something like that? I'm on here looking for direction...I'm a babe in the woods on gas equipment, I've never owned any. I guess I should have said "Warranty", but I have to assume the longer the warranty from a reputable mfr., the more likely it is that it will last at least that long.
The OnlyModulating Condensing boiler on the market that I know of with a heat exchanger warranty where you want it is a Viessmann. Limited Lifetime. The warranty is just like a cast iron boiler 10 years full and then prorated out. Vitodens 100 might be a nice fit.
Good one!"Its not the arrow it's the Indian."
I absolutely agree that we shouldn't size boilers by available radiation or existing size. I was trying to let the OP see for himself that his present boiler is clearly over sized.
There are a ton of different condensing boilers out there. Lumping them all together is is like saying you are not going to buy a Toyota because Yugo makes a bad car.
Buy a good condensing boiler and enjoy the comfort and efficiency they provide.
more estimatesThanks for all the info, I'm going to get more estimates from different contractors, insist on a heat loss analysis and keep looking around for local contractors. It's a little tough to ferret out the ones who will give you their personal best, I guess, & still be reasonable on the budget.
Budgetis subjective LL . What you believe your budget should be may be unrealistic . Most contractors who will do this the way we have explained will be compensated better than those who don't , you may get lucky though and find the guy who is really good at heating and not so good at business , they do exist . In my area the job you are looking for done by a QUALIFIED contractor would probably sell in the low 10s to mid teens . There are a couple guys who would do it for 8-9 and lose their shirts , finding that guy would be good for you . I would use the find a contractor area of this site in your search and if you'll give a specific area where you are located I'm sure that some of us would steer you to someone , that happens all the timeYou didn't get what you didn't pay for and it will never be what you thought it would
There are a couple guys who would do it for 8-9 and lose their shirts ,"There are a couple guys who would do it for 8-9 and lose their shirts , finding that guy would be good for you ."
Perhaps, but even if you found them, is it to even your own best interest to find them?
So you hire them, they come and do a good job on time for the agreed upon price. Right?
Then a year later, when it is time for annual maintenance, they are out of business. Then what? Or, say after another year, some in-warranty part quits. Will your new contractor honor that warranty backed by your former contractor?
For onceI agree with you Jean David . Don't get used to it though . This is exactly why I charge what I charge . To insure that I will still be here later , because I have not invested my life into this trade to do it for less , because this is not a hobby and I don't need the practice . When I am gone my sons who are now both fine mechanics will step right up . Now teaching them the design end as I near the end of my career. Yeah Right , I'll do this till I die .
To the Op . Remember when budgeting for this to be fair was my point . Your new heating system should cost considerably less to operate and you must take that into account when making your decision . In the end you should still be keeping more of your money on a monthly basis , this is what most forget or don't understand , why is beyond me .You didn't get what you didn't pay for and it will never be what you thought it would
thanksI saw another guy this morning and he was good, knowledgeable and measured for a heat loss calculation. So far, he has been the most willing to discuss options. Have another guy coming soon.
I realize budget is relative; and I'm definitely only getting estimates from well established, long-time businesses. I expect to pay a fair price, but when you go into this cold (sorry for the pun), you need to get a real feel for the price range offered. I am definitely going to do this, but "the budget" will ultimately determine if it happens this year or next year.
Rich, I am in the Albany, NY area.
I agree with a heat loss...........................But is somewhat of a moot point if the desire is to have a combi boiler installed.
Not wishing to argue the benefits of a proper sized boiler and an indirect, if a combi is desired, whether it be a Viessmann, Triangle Tube, BAXI, Navien, or whatever, the higher BTU's are there for the domestic to achieve the desired instantaneous water heating.
Again my point is not about the benefits of efficiency, indirect use and whatever but that a super accurate heat loss isn't required, when a combi is 125K to 200K in BTU input potential. At that point whether the home has a heat loss of 40K or 70 K does it really matter?
If the home has a heat loss of 40K or 70 K does sizing really matter?I'd say the boiler's minimum output rate does matter, along with how efficiently the boiler operates towards the bottom end of its modulation range.
So if you wanted a combiwould you go with:
5:1 turndown 125K with a 3 GPM at 77 degree rise domestic flow
10:1 turndown 199K with a 5 GPM at 77 degree rise domestic flow
Depends on domestic requirements right? Both would meet the 40 or 70 K heating requirement
So how important was the accurate heat loss now?
I would want to see the efficiency curvesBut assuming they were both equally efficient at their lowest two firing rates, and otherqise equivalent in terms of quality, controls, etc -- I'd take the 199k.
As I've said here previously, I'd happily give up a few points of top-end efficiency for better performance at turndown. So what if I only get 88% at full fire? There aren't enough hours in that bin to markedly affect my annual usage.This post was edited by an admin on August 12, 2013 4:39 PM.
Water TempI think the heat loss is needed and also measurement of the emitters. The Navien for example, has a max flow rate across the HX of 5gpm, If my heat loss is greater then 50,000 say 80,000 and running on the standard 20 delta-t on the system side, I will have a mix water temp on the system side when piped pri/sec or LLH. In this case if I need 180 degree supply my boiler would need to be making 192. Question is will 173 get me there.
(8-5) *160 + 5*192/8 = 180 Degree System Supply Temp
(8-5)*160 + 5*180/8 = 173 Degree System Supply Temp
I want to know what that mix temp is going to be so I can ascertain as to whether that mix water temp is going to get me where I need to be at or close to design temp. So a heat loss is important because without out it your rolling the dice.This post was edited by an admin on August 12, 2013 4:58 PM.
No CommentI'm disappointed not to receive a comment on why the heat loss is important. Feel left out. Thought I made a valid point, it is reality..
You math is perfect.
Of course you need a heat loss.
It's funny, when no one comments on my posts, I figure I got it right and there is nothing else to say.
Sometimes, I think I said something so wrong, no one wants to comment.No, no one would let that go.
I would take it as a compliment.
warrantyI'm working with the company who did the heat loss calculation and am looking at a Buderus GC124 with a Triangle Tube Smart 40 indirect water heater. I can't say I fully understand the Buderus warranty, how does it stand up compared to other brand warranties?
Warenty for new boilerThese warranties come through the original installers and therefore make the choice.of installer more important-will he be around in 5 years?--NBC
in businessThey've been in business for 36 years, so I'm pretty confident they'll be around.
on my wayJust want to thank everyone who helped & steered me in the right direction.
I'm well on my way to the scheduled installation of a Buderus GC124 with a Triangle Tube Smart 40 indirect water heater. The gas line has been istalled from the street, stainless steel chimney liner swept & inspected, and anticipating double rebates from National Grid that come to $1,120. Also working with a contractor who has bent over backwards to be helpful and guide me through the scheduling with the gas co., rebates, & detailed info as needed. All at a price I like.
What I learned on here was quite helpful.