Buffer tank

NickFl

Brief description.Converting from oil to gas.Upon renovation a few years ago split the second floor baseboard zone into four smaller ones, separate for each bedroom.Baseboard footage is about 50% more than required.The smallest zone is about 7000btu. Heat loss for the house of 3000 SQ. FT came to about 75-80kbtu based on my own calculation. Planning on installing GV90+4. 30 ga. indirect HTP ssp30.Total 5 zones plus indirect. A few estimates that I got, nobody bothered with the heat loss.Estimates ranging $13-18k for the boiler and indirect water heater, some suggesting CI, some HE condensing boiler.Nobody even asked about the size of the house.Nobody suggested a buffer tank either.Boilers offered were at least 130k btu.The question is: do I need a buffer tank to prevent a short cycling, when the only 7K zone calls for heat.Just came from Aaron's and GPS in central NJ, and they hardly know what a buffer tank is. One suggestion was that I only need a buffer tank if burning wood.Please help.
,

STEVEusaPA

Are you married to that specific boiler? Seems too big if your load calc is correct. But if you did a load calc, why the 75-80 and not a more exact number? Or did you just do some rough calcs.

Also, there are better control strategies using TRV's/out door reset, etc. for example, so you don't have an actual 5 zone system to prevent short cycling.
Short cycling solution is a properly sized buffer tank, sized based on the smallest load.
Having 'too much baseboard' will enable you to use a lower supply water temperature.

Even at 3000 square feet are you sure your smallest load (probably a bedroom) isn't smaller than 7K?

If you have to use that boiler, make sure the installer reads, understands, follows the installation instructions, especially p/s piping and calculation of flow rates.

NickFl

Thank you for your reply Steve. The reason for two different heat loss results are two different calculators. You are right, the load is likely to be closer to 5500 btu.The reason for gv90 is that I can avoid chimney liner expense, more confidence in CI longevity and having some sort of condensing if I do it right. As far as the size of the boiler, next size down would be 65kbtu, which I think will be too small. Still, GV90+4 is much smaller than the 130-150kbtu CI offered by professionals. I am open to suggestions, but think that modulating condensing boilers will cost me much more in a long run.

unclejohn

Nick; I don't think that there is a professional on this site that would sell you a 150k boiler for a load of 75k. You need to keep looking for a professional. Also IMO that boiler is junk. But there are thousands upon thousands out there. Cast iron and condensing do not go togeather again in my humble opinion. Look at Triangle Tube.

NickFl

unclejohn, There are professionals that know what they are doing and there are quite a few of them that don't. As a home owner, before I do any type of work , I make sure to educate myself to the point, that I know when the job is done right. It is very time consuming, but well worth it. At that point I usually can tackle the project on my own. I will look at Triangle tube,but still if I decide to go with gv90, what would be the best setup for the system to prevent short cycling?

Jamie Hall

A different way to look at one of @unclejohn 's main points: don't even think about condensing unless the boiler you use is specifically designed to do it. They use quite specific metal alloys to resist the corrosive attack of the condensate.

Then keep in mind that your heat load calculations are for a design day -- and it rarely gets that cold, which means that your actual load will usually be less. Sometimes much less. If you have small zones, even a mod/con boiler will not be able to match the load, never mind a conventional one -- so small zones equals buffer tank, or short cycling the boiler. Take your pick.

NickFl

Jamie Hall. A buffer tank. Even if I can modulate down to 25k btu it is still too much for 5k btu zone. I'll just need a smaller buffer tank. What I would like to get from you guys is some confidence boost that I'm heading in the right direction, as well as some guidance. As I mentioned above, non of the professionals I have invited for an estimate said anything about buffer tank. Just looking at old boiler and matching the output, probably figuring that if it was somehow working before, it will work the same after new install. $15k. later. When the guy I was referred to at GPS, with over 30 years of experience assures me that I don't need a buffer tank with my zone setup and a 97kbtu output single stage boiler, I have to conclude that one of us is wrong, and the experience is not on my side. He also suggested a bigger boiler.
The professionals on this site seem to be much more knowledgeable then those, I've had a chance to encounter.
Suggestions are welcome.

hot_rod

lm a proponent of buffer tank use for the appropiate application You see a trend back to high water content boilers for all the reasons you state

You may in fact be at a below design condition for 80% of the season or more, a tank will certainly help with the system you described.

Let us know if you need suggestions for tanks and piping

NickFl

hot_rod. I'm I right in my estimation for 80ga buffer tank if my boiler output 97kbtu and the smallest zone about 5500 btu to get about 10 min run time? Another question, what kind of buffer tank should I use? Two pipe, four pipe, or electric heater without the heating elements? Don't want to spend more money than I have to, but want to do it right.

STEVEusaPA

Again, why are you married to this oversized boiler? Cheapest one?
Practically all modern boilers can be (have to be) vented thru the wall if you're trying to abandon your chimney.

EBEBRATT-Ed

Yes, you need a buffer tank. I would tighten up your heat loss calculations and pick a boiler that more closely matches the load. Keep in mind if you oversize the boiler you will have to oversize your buffer tank.

I agree with your calculation that to heat an 80 gallon tank & the 5500 btu zone I came up with 11 min. But keep in mind that is only at a design day.

With a boiler that is 75,000 output and the same buffer tank the time increases to 15 min.

NickFl

Steve. Because next size down will be too small, I believe it will outlast condensing boilers with SS primary heat exchanger, I want to be able to service it myself for the most part. This is the only CI boiler that can be vented thru the wall with PVC pipe.
My question was about buffer tank setup anyway. Do you have any info to share in that regard?

hot_rod

What is the tank temperature? off at 180 on 160?

For a homemade solution an 80 gallon electric tank with the two 1" element holes, would be an option. Two pipe arrangement.

NickFl

hot_rod.Looks good, Is this the solution you would recommend? Amazingly I'm totally out of luck finding anybody locally who knows what the buffer tank is.

JakeCK

> @hot_rod said:
> What is the tank temperature? off at 180 on 160?
>
> For a homemade solution an 80 gallon electric tank with the two 1" element holes, would be an option. Two pipe arrangement.

I really need to download the trial version of that software and play.

NickFl

Anybody has any opinion on HTP PHR100-55? That unit may address all my concerns.

STEVEusaPA

NickFl said:

Anybody has any opinion on HTP PHR100-55? That unit may address all my concerns.

Might work/might not. Not my first choice for a mod/con.

Did you try:
https://heatinghelp.com/find-a-contractor/
Otherwise I see a very long thread where you ask about every boiler made.
I hydronics pro evaluating what you have, what you need, what you want is the best way to go, and cheaper in the long run.
You'll need someone to service this unit after it's installed, so your pro will (should) install something they can service, something proven reliable, and something they can readily get parts for.

NickFl

STEVEusaPA said:

NickFl said:

Anybody has any opinion on HTP PHR100-55? That unit may address all my concerns.

Might work/might not. Not my first choice for a mod/con.

Did you try:
https://heatinghelp.com/find-a-contractor/
Otherwise I see a very long thread where you ask about every boiler made.
I hydronics pro evaluating what you have, what you need, what you want is the best way to go, and cheaper in the long run.
You'll need someone to service this unit after it's installed, so your pro will (should) install something they can service, something proven reliable, and something they can readily get parts for.

Steve, the thread would be much shorter if you didn't bother to express your opinions that represent absolutely no value to the topic. While all other posters had something to contribute, which I much appreciate, you are the only one ,who instead of offering a solution, just state that GV90 junk, and PHR100 is not your first choice. If you stray off topic, at least try to backup your conclusions, which I'm sure, many professionals will disagree with.

EzzyT

@NickFl I have a bunch of HTP PHR’s of difference sizes installed and I’m overall happy and pleased on the product definitely has its advantages being a high mass set up. There aren’t many moving parts which is a huge plus. A lot of the systems I tend to see that a modcon boilers are a good fit or are already installed need some sort of buffer tank or high mass modcon instead and the PHR is a great fit.

STEVEusaPA

NickFl said:

STEVEusaPA said:

NickFl said:

Anybody has any opinion on HTP PHR100-55? That unit may address all my concerns.

Might work/might not. Not my first choice for a mod/con.

Did you try:
https://heatinghelp.com/find-a-contractor/
Otherwise I see a very long thread where you ask about every boiler made.
I hydronics pro evaluating what you have, what you need, what you want is the best way to go, and cheaper in the long run.
You'll need someone to service this unit after it's installed, so your pro will (should) install something they can service, something proven reliable, and something they can readily get parts for.

Steve, the thread would be much shorter if you didn't bother to express your opinions that represent absolutely no value to the topic. While all other posters had something to contribute, which I much appreciate, you are the only one ,who instead of offering a solution, just state that GV90 junk, and PHR100 is not your first choice. If you stray off topic, at least try to backup your conclusions, which I'm sure, many professionals will disagree with.

I didn't bash either boiler and definitely didn't call your first choice junk, that was a different poster (pay better attention), and gave you sound advice, and didn't stray off topic. BTW you thanked me for responding in the first post.

I told you your initial boiler was the wrong size. You seemed like you wanted that boiler anyway because it was the cheaper route.
I'm not at your house which is why I recommended you find a professional on this site to properly advise you.
It's the same conversation you and I would have on the phone.

And I didn't draw any conclusions, nor do I need to do anything more than give you my opinion.

@EzzyT is a top notch guy. He likes that boiler.

NickFl

Steve, I do apologize, I'm sure you mean well.
After being quoted by a professional GWB8-150E Lennox boiler, (which is even bigger than what I have now) for my project and the cost, I have decided to do the installation myself. I will follow your advice (make sure the installer reads, understands, follows the installation instructions, especially p/s piping and calculation of flow rates.) I will learn everything there is to learn about the boiler I'm going to end up installing, which is likely to be PHR-100. It is not going to cost any more than GV90 with buffer tank, and the installation is more simplified. Whatever the end result will be, I am sure it will be much better then if I had blindly entrusted myself to a professional that doesn't know what he's doing. And about $ cheaper. Don't consider myself a plumber, but have done a lot of it over the years, No boilers though.
I wonder if anyone can recommend a distributor within 50 miles of Flemington NJ, where I can get that HTP PHR100.

EzzyT

Aaron’s & Company carries HTP products.
Before you decide to take on this project do have the proper equipment and know how in order to do a combustion analysis and gas pressure readings to set up the boiler?

NickFl

EzzyT. What kind of equipment do I need? You probably think that I'm clueless, and I hate to admit it ,but you are absolutely right. I'll get what I need to get, and learn what I need to learn , before I start the installation. If you can give me any advise( excluding one, to let somebody else to do the installation) I'd be very grateful. From what I see, you know what you are doing, and talking about. Would recommend you without any hesitation.

EzzyT

Before going out and buy the proper equipment I would suggest you go and take some classes. Sign yourself up to take some of Tim McElwain hands on classes on gas and combustion.

Rich_49

NickFl said:

Anybody has any opinion on HTP PHR100-55? That unit may address all my concerns.

The Pioneer is a low maintenance , quality unit and with 55 gallons it provides a nice buffer . have installed many with zero issues yet over the years . Besides Aaron and Company , Atlantic Also carries the line .

NickFl

Was little more difficult then expected to get one, considering, I had to have it by Friday. Fortunately Aaron happened to have one in stock. Ferguson , F.W.Webb, carry them also, but don't stock them.The rest of the supply houses don't know what the HTP is. While driving the unit that miraculously could be squeezed in a minivan without removing it from the crate, noticed the sound of a liquid splashing inside the unit. Is it normal?

Docfletcher

Might be pre tested at factory.

NickFl

Big thanks to everyone, who responded to my request. While all of you guys have your preferences, one thing you all have in common, is the ability to do the job right. I am very lucky to find this website. Because of that I did not fall a victim to a boiler swapping "professionals".

EzzyT

@Docfletcher has it right, that’s is from factory testing.

john p_2

Nick,
I hired Langans Plumbing & Heating our of Howell, NJ not to do the job but as consultants and couldn't be happier.
They provided me with a design, drawing, list of equipment to use, did the start up and most importantly they sized it correctly.
I now have a near 3000sq. ft. home that I heat, cook and wash & dry clothes with gas and have never gotten a gas bill above $200, where having previously had one zone hot air heat I used yo get $450 gas bills.
I'm not advertising for Langans as much as suggesting this might the route you should take and there are qualified contractors on this site to hire. Thanks

Docfletcher

That looks jaw dropping good, thanks for the photo. I'm glad it worked out A OK for you.

Zman

I am not sure why this job is even a candidate for a buffer tank. Assuming you are willing to abandon the idea of a 340# on/off dinosaur, you could simply install one of many 85k btu modcons with 10-1 turndown and be done with it. Imagine 2 people just carrying it down the stairs and hanging it on the wall like a picture. These units are at least as reliable as a GV and you literally will have to look at the screen to know it is running.
I like the WHB-085 but others will have equally good recommendations. http://www.lochinvar.com/_linefiles/KHBWHB -04.pdf

Zman

I didn't notice that you had already selected a pioneer. That is also a good choice. The water sloshing is not an issue, the factory probably water tested it and did not get it all out before shipping.

NickFl

OK. The Pioneer is in. Still have to finish the exhaust and electrical.The big question is about the wiring. Should I wire it just like the manual says to connect indirect water heater or use my existing Taco and set it on priority?

Zman

I am not familiar with that model @Rich_49 would know the little details.
I would let the boiler handle the DHW priority. That way it can overide the outdoor reset when the domestic call occurs.

john p_2

Nick, can you post some pics?

EzzyT

As @Zman has said wire the dhw pump directly into the Pioneer control board.

NickFl

Thank a lot guys. Hopefully will finish it today and post some pictures.

mattmia2

I had considered setting up an indirect with a thermostatic valve on the DHW outlet and opening its zone when a low output zone was calling by itself in combination with using a condensing boiler with a 5:1 or 10:1 turn down ratio.

I think even without using the indirect as a buffer there are controls on the condensing boiler to let it lengthen the cycles either through a timer or a large temp swing.

It seems the most important thing is to make sure the smallest zones will have the min flow of the boiler when calling alone.

NickFl

Finally gave it a test run. Got past F9 code after five or so attempts. Everything seems to be working except the indirect water heater SSP30. Thermostat calls for heat, but the system is not powering the circulator. What the heck I'm doing wrong?

mattmia2

Is the indirect a separate circulator or is it zone valve controlled? There are menu settings to control if it is its own pump or there is a system pump that comes on with a dhw call.