Need some help - New homeowner very confused

Ironman

That's a very good boiler from a quality installer.

I would not look any further.

NickB2005

Ironman said:

That's a very good boiler from a quality installer.

I would not look any further.

Haha fair enough!

Chester

Charlie from wmass said:

Way back in the Dark Ages when I started doing this I was told it is 65 BTUs per square foot for Berkshire County Massachusetts.

I live in Maine in a pretty well insulated 1400 sq ft Cape. My heat loss is around 15 BTU/square foot.

Charlie from wmass

That is a very well insulated house.@Chester

NickB2005

Hey all. I got one more quote that came in finally after a week and a half. What do you think of this model? I am thinking it's between this and the Utica boiler w/the super stor indirect. Figured I'd throw this out there though.

Equipment:

1 Lochinvar WHN110 110K Input 96% Efficient Modulating Gas Boiler

1 Lochinvar SIT050 50 Gallon Stainless Steel Indirect Water Heater

1 Grundfos ECM Variable Speed Circulator Pump

1 Taco ZVC404 Zone Valve Control Board

2 Taco ZA024Q4A1 Sentry Zone Valve

NickB2005

Hatterasguy said:

The use of a single pump and zone valves is highly desirable for efficiency and this should be mandated no matter which contractor is selected. Anyone who uses pumps (plural) is drastically ovepumping the system and the resulting DT is in the toilet. The efficiency of a mod-con is dependent on getting the return water as cool as possible. That requires careful control of the flow rate, something multiple pumps will not do.

The WHN110 is too large for your house.

The WHN110 has a minimum firing rate of 21K and will short cycle endlessly on all days that are warmer than about 40F.

This contractor should be familiar with the Lochinvar KHN085 which has a low firing rate of 8K and will offer far greater efficiency than the WHN110.

Thanks @Hatterasguy! Do you still think Utica setup with the SuperStor is probably the better option for me though?

Charlie from wmass

I would ask the contractor installing the Utica if they could use zone valves and a variable speed pump has the boiler size is better. The issue that has come up currently is that from an engineering standpoint a single pump the zone valves can give you better efficiency. From a reliability standpoint circulator pump have a much lower field rate than zone valves. Many good contractor above a certain age preferred one circulator 1 Zone.

NickB2005

Charlie from wmass said:

I would ask the contractor installing the Utica if they could use zone valves and a variable speed pump has the boiler size is better. The issue that has come up currently is that from an engineering standpoint a single pump the zone valves can give you better efficiency. From a reliability standpoint circulator pump have a much lower field rate than zone valves. Many good contractor above a certain age preferred one circulator 1 Zone.

Well the Utica install would be from Bob on these forums. Bob Gagnon. He's supposed to be swinging by this morning to check it out as he quoted it based just on the info I gave him.

Charlie from wmass

On this form are many different points of view from homeowners to engineers to install and contractors. Lock 6 of us in the room and you'll get 12 different opinions. And at least five of them will be right.

Charlie from wmass

What if the pumps are all E007 pumps tuned to required flow?

Charlie from wmass

With rebates variable speed pumps are cheaper than fixed speed in my area.

Charlie from wmass

I see. Yes it would

Gordy

One really has to ask the question what if any boiler with out a buffer either as part of the unit, or as an accessory would not short cycle above 40-50 degrees. Depends on how that warm OAT comes in on the weather pattern. Add small zoning .........

njtommy

The taco VR1816 is a very good solution with its adjustablity.

hot_rod

Hatterasguy said:

Gordy said:

One really has to ask the question what if any boiler with out a buffer either as part of the unit, or as an accessory would not short cycle above 40-50 degrees. Depends on how that warm OAT comes in on the weather pattern. Add small zoning .........

You have a chance with the 10:1 boilers with a bit of mass in the system.

You also need to define "short cycle". You can program any of them to prevent a restart for, say, 20 minutes if they shutdown on HL. The cycle would then be 2 per hour. Not miserable.

No, you can't use tiny zones.

Ramp delay feature is nice also, keep it at 20% for 20 minutes, or whatever fits.

Gordy

It would seem that some how being able to tie ramp delay with OAT would be a nice option.

Brewbeer

@NickB2005 Did you do the heatloss calcs over the weekend?

Some modern mod con boilers let you program the space heating temperatures in a way that may help reduce short cycling. For example, the Lochinvar WHN allows you to set up the boiler to exceed the reset curve temp by as much as 15 degrees, and since the higher the emitter temp, the more BTUs they emit. Such a feature will probably help with the shoulder seasons, but probably not if you have small zones.

Did you do an emitter survey?

NickB2005

I didn't end up doing the heat loss. I went with Bob as recommended from this forum and he said he'll perform an actual heat loss, but the early estimate is he thinks 70-80k btu heat loss. I am happy with the selection.

Brewbeer

How about the emitter survey? If you are short on emitters the mod con option may not be the best.

NickB2005

Brewbeer said:

How about the emitter survey? If you are short on emitters the mod con option may not be the best.

I must've missed that piece. I have a ton of baseboard everywhere. I know bob measured the baseboard today too.

Charlie from wmass

Contrary to what I have said in the past mod cons can still save a significant amount of fuel on systems that were originally designed for 180 degree water. Especially with outdoor reset and the fact that we almost never see design days. Also mod con boilers with proper yearly maintenance are showing to be much more reliable than I had initially encounter. Most of the mod con nightmares that come here to the wall are due to improper installation or poor maintenance or both.

Charlie from wmass

@Hatterasguy you know if he just uses a buffer tank it will be fine.

Brewbeer

It really gets down to supply water temps.

If you have typical baseboard that is rated at ~800 BTUs per foot at 180 degrees, that baseboard is only going to shed about 125 BTUs per foot with a water temp of 100 degrees. If we use the 15,000 BTU minimum fire rate of the SSC-75 and 100 degree supply water, ~120 feet of baseboard is needed in order to match the output of the boiler on low fire. If the supply water temp is 110, ~80 feet of baseboard is needed, if the supply water temp is 120, ~60 feet of baseboard is needed, and if the supply water temp is 130, it takes ~45 feet of baseboard to match the low fire BTU output of the SSC-75. This is important because the "con" of the mod-con boiler is condensation, which very generally occurs at water temps of 130 and lower. The lower the water temps, the more condensing that occurs, and the higher the efficiency, as shown in this graph: https://csemag.com/uploads/RTEmagicC_CSE1206_FHVAC_1.jpg.jpg

If you baseboard is rated at less than ~800 BTUs per foot at 180, even more baseboard is needed to match the boiler output at any given supply water temp.

unclejohn

Hatterasguy said...
As an example, your TT Solo 80 will only get down to about 14K net output. That's sufficient to heat the building at 40F (say 50K heatloss). Above 40F, it has to start cycling.

What Building are you going to heat that has a 50k heat loss with a boiler output of 14K.

The fact is boilers come in specific sizes. A example on this thread said the heat loss was 80243Btu. You are not going to find a boiler at that specific rate your going to find one at 80k 90k 100k ect. You also will not find a boiler that will match your low load requirement, even taking your best SWAG. You will never get a boiler to run all season without shutting off so stop trying.

Charlie from wmass

As efficient as practical not as efficient as possible. We all have budget constraints. Whether we simply have no more money to throw at it or we have no desire to throw more money at it, there are constraints.

Charlie from wmass

I don't know if you are paying an awful lot for a cast iron boiler or if you're getting a really good deal on the mod con but I just checked and the mod con with 10.1 was 112% more money than the cast iron 84% a.f.u.e..

Charlie from wmass

Uft was not availible in my area
EP was

Charlie from wmass

Why install a mod con if you're not going to use the bells and whistles?

Canucker

@Hatterasguy I agreed with @Charlie from wmass but I still think it is useful to find out what is efficient as possible, for the ones that can afford it, if for no other reason than to raise the ceiling of what can be achieved. Efficient as practical springs from what is possible, no?

Charlie from wmass

@Hatterasguy I will look into the uft. Like I said my supply chain of HTP is not like yours. I also see how that is contrary to logic due to my proximity to HTP. I did not realise how a few sensors and some differences in programming affected the cost. I agree with you as to the apparent contradictory nature of my two posts. If all I am shown are $3k boilers as my mod con option and it is proclaimed the bells and whistles are the only way to achieve shangri-la what else would you expect me to say. Now I know of another option for my customers and it opens options for as efficient as practical. ( you know some smart people btw)

Charlie from wmass

What is the pressure vessel made of?

Charlie from wmass

The vessel or just the heat exchanger. Some one was pushing a plastic one with a stainless steel fire side. Who was that?

Charlie from wmass

Plastic Contender. It is not in the new catalog.

Canucker

Hatterasguy said:

Canucker said:

@Hatterasguy I agreed with @Charlie from wmass but I still think it is useful to find out what is efficient as possible, for the ones that can afford it, if for no other reason than to raise the ceiling of what can be achieved. Efficient as practical springs from what is possible, no?

I fail to understand the agreement or the disagreement.

The goal was to procure a 10:1 mod-con. Charlie suggested that the cost would be a factor and you might have to settle for "efficient as practical".

I then offered the UFT as a boiler that would meet the cost goal and still provide the 10:1 modulation and would be the definition of "efficient as practical".

He now commented that a mod-con without the bells and whistles wouldn't be desirable which appears to be in direct contrast to "efficient as practical".

And, now you agree with Charlie............but...........which side of the argument (if there is one)??

Sorry @Hatterasguy , I misunderstood the context of efficient as possible. I took that to mean there were no budget constraints, which I believed @Charlie from wmass meant there were when he suggested efficient as practical. Semantics in this case

Jamie Hall

I just decided to come back to this thread -- seems to me that we are a good fur piece from the poor confused original poster, but that's OK -- it's fascinating anyway.

Seems to me a good bit of the discussion has an apples an oranges flavour to it...

Sometimes we are talking about achieving the maximum efficiency, regardless of cost. Which is a worthy goal, and perhaps there are some folks here who really can go in that direction (I can't). Leaving considerations of what's out there in the building --radiation and all that trivia -- the key to it is, of course, turndown and maintaining efficiency across a wide range of firing rates. I don't doubt that 10:1 on gas is achievable, although I would be very interested to know what the actual efficiency curve of a real world boiler over that range is. It would, of course, have variable flow rate through the heat exchanger, but I really do wonder if a given peak efficiency -- let's pick 96% as a nice round number -- can be maintained across the 10:1 range without some means of controlling air flow as well as fuel flow other than a venturi, which won't do it. Are there real hard figures available on that? And what is the situation for oil? I do know that gas turbines -- which are oil fired -- have wider "turndown" ranges (power output ranges, in their case), but they also have remarkably sophisticated air flow management and fuel flow management to do it (assorted computer controlled bypasses on the compressors, complex combustors, 3D cams or computer controls in the fuel flow metering, etc.). What's available in heating?

It seems to me that at least 10:1 ranges should be feasible for both oil and gas. It also seems to me that it would require some pretty sophisticated controls, including at least O2 sensors and the like. Has anyone done this?

But then... there is the question of cost vs. benefit -- both in terms of original equipment costs and in terms of maintenance. As a very rough number, most of the more sophisticated control systems mentioned above have rather fierce maintenance requirements, and expected lives on the order of 1,000 hours between major checking. Is the fuel saved going to pay for the increased costs of purchase and maintenance? Where is the break even on sophistication of control and flexibility of output vs. old-fashioned on/off running?

All valid questions!

Charlie from wmass

@Hatterasguy it was the vessel that was plastic.

Charlie from wmass

@Jamie Hall HTP and Weil Mclain both have 10.1 turn down. They use the blower motor speed to control the flow of gas. I believe this is still maintained by the use of negative outlet pressure at the gas valves. In other words the blower has to draw the gas out of the gas valve for combustion. The faster the blower spins the more gas it draws and based on the engineering the combustion efficiencies remain steady throughout the blower speeds. Oil would be a much more complicated situation. Or maybe not.

Charlie from wmass

I don't know the durability I would not touch it with a ten-foot pole. As you noted they did quit making it.

Jamie Hall

Charlie from wmass said:

@Jamie Hall HTP and Weil Mclain both have 10.1 turn down. They use the blower motor speed to control the flow of gas. I believe this is still maintained by the use of negative outlet pressure at the gas valves. In other words the blower has to draw the gas out of the gas valve for combustion. The faster the blower spins the more gas it draws and based on the engineering the combustion efficiencies remain steady throughout the blower speeds. Oil would be a much more complicated situation. Or maybe not.

That makes sense. Should work pretty well... Just off the top of my head I would think that with oil the biggest problem would be maintaining a reasonable flame pattern over a range of fuel flows.

Charlie from wmass

Weil Mclain is 155000 BTUs. Not so huge of a deal. I thought that was a long island accent. Weather the use of a hydraulic damper and varying the delivery pressure of the oil they already have modulating oil burners for commercial boilers. The issue is that they have not taken the time to engineer it for smaller residential boilers at least in the American Market. I bet you the European Market has them