NEW Indirect needed, Please Help

Diggles007

Good day everyone.
Please forgive me as I am not a pro on these topics and new to this site. (Appreciate your help)

So I have a BAXI Luna 310 Comfort Fi (I believe) have pics to share if needed, connected to a hydronic Lennox Air Handler, and a BAXI Dual Coil 180 Liter (47.5 Gallon) Indirect Tank (Poorly installed from the previous home owners) My Baxi indirect is showing signs of a minor leak at the base (this system is about 14+ years old (It looks like it may be the inlet that is ever so slightly leaking very slowly) hard to tell, but there is always a small amount of water at the base. Condensation, I'm not sure, but I am going to replace it to be safe.

My question is, will an NTi S40 / or NTi S50 work with my current setup?
And which one would you choose for efficiency? My home is under 2000 square feet, excluding the finished basement, and its two adults and one child, 4 bathrooms 3 showers. Our current setup we never run out of hot water, but I do notice my Enbridge gas bill here in Ontario is always quite high (Without a rental) im assuming this is due to my older combi that is rated for 85.5% AFUE efficiency (if I have my model correct)

I am not knowledgeable on the Boiler output (MBH) that is required on these tanks as the S40 says 155, and the S50 says 180. My current baxi combi I think has a max BTU output of 105,000. So I am confused if they are compatible?

Any ideas would be great, and whatever option indirect I choose id like it to work with a new Combi / Boiler down the road from NTi or Navian. Which I'm sure would be fine with a higher BTU output (which I also don't want to oversize)

Please forgive me for my ignorance, I am just stumped as to what the right thing to do is for the replacement, and improve efficiency if at all possible with a new indirect tank.

I appreciate everyone's time and assistance.
Please advise and help if you have any ideas.

THANK YOU!

mattmia2

The efficiency will be about the same between different tanks of the same series. tanks with better insulation will be a little more efficient. Most indirect tanks will be compatible with most boilers.

If your current tank is really dual coil it will have a lot more transfer area than a single coil tank so it can heat more water from the boiler. I'm not sure if it is a steel or stainless tank. If it is a stainless tank and it is just leaking at a fitting it is probably worth fixing that instead of replacing the tank.

It isn't likely that anything you do with the boiler or the tank will significantly change your heating bill, A 10% difference in your bill won't be much. Adding insulation and reducing infiltration of the building envelope will do a lot more to save you fuel.

Diggles007

Thank you so much for the quick reply! I really appreciate it!


I attached a pic of the specs of the indirect dual coil. It seems like its steele, and the dual coil was made for a solar panel installation - which was never used. It seems to be very well insulated with a jacket and polythreonine insulation.
https://cozycomfortplus.com/wp-content/uploads/2017/12/Brochure-Dual-Coil-Indirect-Storage-Tank.pdf

If fixing the leaking inlet (if that is the cause of the issue is not possible) would you think the NTi S40 would be a suitable replacement? with 7.5 gallons smaller than my current baxi. Would this be an issue? or would the S50 be a better suitable replacement?

You mentioned adding insulation and reducing infiltration to the building envelope will increase efficiency. Do you mean to my home in general or the indirect tank iteslf?

Thank you so very much.

SuperTech

Insulation and air sealing of the home will make the greatest impact on efficiency.  For sizing the indirect tank you have to consider how much hot water you use. You might not need a tank as large as your current. 

When the time comes to replace your Baxi boiler I recommend staying away from anything made by Navien.  Proper sizing and installation make or break how efficient and reliable a boiler is, but I've found that Navien boilers are problematic even when sized and installed perfectly. 

Diggles007

That is great to know, I completed an attic insulation in my home when we moved in and upgraded it to r65 I believe. We also did some air sealing and added heat reducing window film as the home faces west and it gets very warm in the summer (not sure these did anything) but the air sealing and attic insulation has helped for sure.

We have 3 showers, 2 washing machines, 1 dishwasher, 4 bathrooms. But its only me and my wife and our 2 year old son. And our current setup has never let us down with heat / domestic hot water during colder months and showing at the same time. We may only notice pressure loss - but heat loss was never an issue.

I am unsure if going to the NTiS40 would be A. a good product that is insulated and efficient .. or B the S50 which is a little larger than what I have. (My current tank size is 47.5.) would going to the 40 work for us, and require less heating up as its smaller?

Thank you so much for your time and responses everyone.

Hot_water_fan

How much gas do you actually use per month? Can you break it down by month? 

Diggles007

Thank you, so for my under 2000 square foot home with 2 adults and one child we use 422 cubic meters of gas in February, 286 in January 221 in March. (This may not be that high, but for our small family I thought it was in comparison with my neighbors. Average seems to be around 350 cubic meters monthly. (in the cold months)

Thank you

SuperTech

In my experience a 40 gallon water heater should be suitable for your needs. A 50 gallon definitely wouldn't be too much of a difference to make a noticeable difference in energy consumption. One thing to pay attention to is how much water volume the heating coil contains. An indirect with a larger coil will recover faster from a long shower or other high demands for hot water. Make sure its installed with full size piping.  I often see indirect ms that should have 1" piping to coils installed with 3/4" pipe.  This will increase recovery time.

Lyle {pheloa} Carter

It never hurts to contact the manufacturer to find out if there may be a warranty on the tank..

EdTheHeaterMan

@Diggles007, many of the manufacturers of Indirect Water Heaters offered a Limited Lifetime Warranty on those tanks. Have you looked into the possibility of getting a replacement tank under warranty? 14 Years is not that long for an indirect, unless it was cheaply made and only came with a 5 or 10 year warranty.

GGross

Warranty is only for the original owners in almost every instance

Hot_water_fan

Thank you, so for my under 2000 square foot home with 2 adults and one child we use 422 cubic meters of gas in February, 286 in January 221 in March. (This may not be that high, but for our small family I thought it was in comparison with my neighbors. Average seems to be around 350 cubic meters monthly. (in the cold months)

That's not so bad. DHW isn't much of that, most will be heating, so neighbors usage should be pretty similar.

mattmia2

I would consider that the kid is going to keep using more and more hot water until they finally leave.

Diggles007

Thanks everyone!
I tried to get in touch with baxi, I think they are primarily out of the uk. And my warrant unfortunately doesn't extend too long for this model. Also unsure how they could help me as there are not many if any distributers that I found for new products in the area.

I think I am leaning on the NTi S40. Oddly enough the tank size specs says the physical tank size has a larger footprint. And I am choosing this because I THINK the smaller the size the less recycling of heat will take place?

Or should I just go for the S50 size? for peace of mind? Again my current tank is 47.5 and we always have hot water no matter what for our needs.

Here is the NTi Tank sizing and specs:
https://ntiboilers.com/product/trin-stor

Hour 1 recovery, 140°F for the S40 is 313 Gal, and heat recovery for the S50 is 251 Gal

I dont understand the specs too well in terms of sizing of the coils, but all that information is listed in the above link if someone could help me determine which one would be more effective?

Thanks so much (Such a helpful website)
Hope everyone is having a great day.

mattmia2

Those numbers are for comparison more than what will happen in your application. The incoming water temp, final water temp, size of the boiler, and actual usage pattern all have a big effect on the actual amount of hot water produced by a given system. The 2 models you are comparing both have the same coil in them, one is just in a bigger tank. The spec of feet of head is a measurement of the resistance of flow through the coil, it is used to size the circulator to get the needed flow rate.

Also if you are buying a stainless steel tank, find out what the chloride content of your water is, the tank will have a spec for the maximum amount of chloride allowed in the water.

WMno57

BAXI Luna 310 Comfort Fi (I believe) have pics to share if needed, connected to a hydronic Lennox Air Handler

Assume your home has ductwork? Air Conditioning? Any radiators or radiant floor heat? Is the Baxi Luna 14 years old?
Your greatest potential for savings on fuel may be to switch to a forced air heat pump for space heating, and a heat pump or electric resistance water heater.
What is the monthly fixed charge on your gas bill before consuming any gas?
Gas forced air furnace is also an option.
Your winter gas bills tell how many BTUs is takes to heat your home and domestic water. The summer month bills tell how many BTUs it takes to heat your water alone.
With the above information, it is possible to estimate how many Killowatt hours of electricity it would take to heat both your home and water.
Until those numbers are crunched, don't spend any money on a 14 year old system.

Diggles007

Thank you! Yes my home has ductwork, and a dedicated AC unit. (Also old unit) 14+ years old. No radiant floor heat. Yes the Baxi is 14 years old.

I appreciate the insights.

With the given info to replace my current dual coil baxi (I think it dual coil for the optional solar that was never hooked up) would you go with the S40 by NTi or the S50.... or it wouldn't matter with efficiency choosing the smaller size?

And are these reasonable decent tanks? Insulated well? Good reputations in comparison with what I currently have?

Thank you

Diggles007

Lets take a vote for my new indirect tank:
My current Baxi Indirect is dual coil (I think for the solar option that was never used) 47.5 Gallons

OPTIONS:
1. NTi S40
2. NTI S50
3. Alternative suggestion that I should explore (Better brands, turbomax ETC.

My goal is to make the indirect better than what I currently have for efficiency and keeping the same constant hot water for my domestic hot water and hydronic furnace / air handler to keep my home warm and comfortable (I am in Ontario and our winters get very cold)

My home is under 2000 square feet (excluding the basement) with two adults and one child. And this is connected to my Baxi Combi 105,000 BTU Luna Comfort 310 fi.
Thank you!!

Larry Weingarten

Hi, You currently have a tank just under 50 gallons. It looks like you're comparing a 40 and a 50 as replacements. The 40 will have slightly less standby loss, but with fewer gallons stored, a greater chance of running out of hot water. If you have a tub that gets used, I'd go with the bigger tank. Otherwise, consider installing a low flow (say 1.5 gpm) showerhead and go with the smaller tank. That arrangement would have somewhat lower energy costs and still meet the need.

Yours, Larry

Diggles007

Thank you so much I am leaning towards the NTi S40 as well based on the minor lower energy cost to refill etc. And all of our showers except the master has a low flow shower head on it (My wife hated the low pressure so I removed the moen flow restrictor from the shower head (not sure what GPM this is now functioning at) but we don't take long showers and average 6 minutes in there if that.

As you can tell this is all new to me.... based on the above specs from the link provided how long does it generally take for the 40 to refill itself with my current Baxi? I don't know how to calculate this and dont understand the specs too well to know which tank refills faster (im assuming the s40)

And would the S50 have a longer standby loss due to its slightly larger size?

Thank you!!

Hot_water_fan

Truly don’t worry about standby loss. It’s not worth your time. 

Diggles007

Thank you for the insights:

I also wanted to ask about this part, my current baxi combi is maxed 105,000 BTU's where the NTI boiler outputs for the S40 and S50 are much higher... I was leaning on the S40 also to not put a strain on my current Baxi as its asking for a smaller amount.

Or am I not reading this right for compatibility with my current Baxi?
Thank you

Hot_water_fan

Don’t worry about that either. Your appliance is smaller. This means it’ll recover slower. That’s all. It won’t “tax” it any more or less. 

Diggles007

Thank you so much good to know! I appreciate it!

Also, with my size combi, what is the average recovery time for an NTiS50 sized tank more or less?
Does this actually empty? Or it is always full and heated.

Nonetheless, what is the average time it would take to fully recover a 50 tank?

Thank you!!

hot_rod

The recovery will be based on how cold the tank is starting from, and the gpm flow you can send to it. With that boiler, 9- 10 gpm if you are piped with 1" or larger.

You'll probably be running more like 90,000 btu/hr to the tank, a bit less that what their performance graph shows

Diggles007

Thank you, that is good to know, unfortunately my pex connections to the boiler to the air handler and indirect are 3/4 inch pex.

mattmia2

If anything the smaller boiler would be an argument for a larger tank. The larger tank holds more water so there is more energy accumulated in the tank. The boiler adds energy to either tank at the same rate so there is more hot water available with the larger tank.

The way the tank works is cold water is piped in to the bottom of the tank(or has a tub inside the tank that directs it to the bottom of the tank) and hot water is piped out of the top of the tank. When you open a hot water tap cold water flows in to the bottom of the tank an pushes the hot water out of the top of that tank. The water mixes to some extent. There is an aquastat on the tank that calls for the boiler to start heating the tank when the temp of the tank drops a certain amount and shuts off the boiler when the tank reaches a certain temp. it is a continuous process with the boiler cycling on and off. As long as you are removing less energy in the form of hot water than the boiler is adding you will have continuous hot water. If you remove energy faster than the boiler is adding it you will run out of hot water.

The water in the tank tends to form a hot layer on top and a cold layer on the bottom so if you run out it tends to be abrupt when you hit the boundary of that stagnation.

hot_rod

Yeah. the 3/4 pex will reduce the amount of boiler capacity you will get to the tank.

Go with the smaller tank, if you need extra output raise the tank to 150F and use a mix valve.

That turns the 40 gallon tank into a 53 gallon drawdown

Hot_water_fan

Most all Americans don’t have an indirect but I don’t know about Canadians. Standalone tanks often have much less powerful heaters (mines only 4.5kw, or 15,000 btus). Somehow we get by . 

Might be worth considering just moving to a standalone. They’re usually much cheaper and that might fit your needs better. 

Mad Dog_2

TURBOMAX...Mad Dog