New boiler and slant-fins

TerrS

@pecmsg can I ask what's wrong sending some water up to the 3rd floor? I mean it has plaster walls and is finished but very old.

I mean whats the difference if I had a thermostat for up there set at 50 degrees, instead,  of sending alittle flow each time the boiler fires?

109A_5

Hello @TerrS,

TerrS said:

@pecmsg can I ask what's wrong sending some water up to the 3rd floor?

I thought your goal was to reduce your fuel bill ? Sending heated water to a place that is probably getting heat from the 2nd floor is a waste, and your are paying for it. If the only pipes in the attic that could freeze are the heating pipes I would close the dampers on the baseboard an make every effort to (by restricting the heat that gets to the attic space) keep the attic at 40° I would have the basement at about 55°.

Also as much as folks love their fireplaces often their draft sucks the heat out of other parts of the house just making the boiler run more.

hot_rod

109A_5 said:

Hello @TerrS,

TerrS said:

@pecmsg can I ask what's wrong sending some water up to the 3rd floor?

I thought your goal was to reduce your fuel bill ? Sending heated water to a place that is probably getting heat from the 2nd floor is a waste, and your are paying for it. If the only pipes in the attic that could freeze are the heating pipes I would close the dampers on the baseboard an make every effort to (by restricting the heat that gets to the attic space) keep the attic at 40° I would have the basement at about 55°.

Also as much as folks love their fireplaces often their draft sucks the heat out of other parts of the house just making the boiler run more.

If the attic is not well insulated from the outside, including the rafters, that could be an area to save some $$, by isolating and draining that zone or loop. Same with the basement. Since the warm air currents from the fins rise, your greatest delta T is at the ceiling. Be nice to have R 30 or more up there if any heat is trying to stay in.


I doubt that your fireplace is a condensing type, so it cannot achieve much more than mid 80% efficiency. The boiler may be running higher % so it would be less $$ to run the boiler and fin tube. Unless you are after the radiant feel and ambience

Jamie Hall

TerrS said:

@pecmsg can I ask what's wrong sending some water up to the 3rd floor? I mean it has plaster walls and is finished but very old.

I mean whats the difference if I had a thermostat for up there set at 50 degrees, instead,  of sending alittle flow each time the boiler fires?

There's a very real tradeoff here which most people overlook completely. If you have a finished space of that sort, and it is connected (more or less) to an occupied dwelling, then you have two, and only two, choices: keep the space above the dewpoint of the air in the rest of the dwelling or kiss the plaster goodbye. There are good dew point calculators available, but in general, in most houses, I've found that the temperature must be kept above 50 in such spaces, and 55 is safer.

Granted, you will pay a little more for heat -- but how much more? If the total cost of repairing the damaged plaster is taken into account (assuming you could actually find someone to do it) you may find that you could buy a lot of fuel oil or LP or whatever with that money... (in one house I care for, I could buy 5,000 gallons of fuel oil at today's prices for what it cost to repair the damaged plaster).

Think about it.

pecmsg

Jamie Hall said:

TerrS said:

@pecmsg can I ask what's wrong sending some water up to the 3rd floor? I mean it has plaster walls and is finished but very old.

I mean whats the difference if I had a thermostat for up there set at 50 degrees, instead,  of sending alittle flow each time the boiler fires?

There's a very real tradeoff here which most people overlook completely. If you have a finished space of that sort, and it is connected (more or less) to an occupied dwelling, then you have two, and only two, choices: keep the space above the dewpoint of the air in the rest of the dwelling or kiss the plaster goodbye. There are good dew point calculators available, but in general, in most houses, I've found that the temperature must be kept above 50 in such spaces, and 55 is safer.

Granted, you will pay a little more for heat -- but how much more? If the total cost of repairing the damaged plaster is taken into account (assuming you could actually find someone to do it) you may find that you could buy a lot of fuel oil or LP or whatever with that money... (in one house I care for, I could buy 5,000 gallons of fuel oil at today's prices for what it cost to repair the damaged plaster).

Think about it.

The OP's residence is 119 years young. The attic in question is finished but not used. Like my house any work required removing the horse hair plaster and replacing it.

Conservative guess is a 10 - 20% reduction in fuel usage it that rad is disconnected and drained. When the time comes she wants to use the space it can be reconnected. As far as the plaster it would have to be replaced just to add insulation and wiring.

TerrS

@pecmsg correct. As I have been going thru my house over the past 31 years, I have been dropping all the plaster and lath. Insulating and putting up drywall. The attic is used as storage only. So it's cold or hot depending.

It would be interesting how you calculated that savings. My issues as I see them, are I boil the ocean as it's a 6gallon cast iron tank, that I am putting 150btu burner too. 20 minutes later I am just starting to get heat it took to make 120 degree water and 10-15 more minutes for 180 degrees to really heat my house. There is probably around 2 gallon of extra water, given 80ft of 3/4" pipes volume. As it circulates it its added to the other 3 zones. So I can't see that much of a savings. Plus because of the bedrooms being right below the attic, that becomes a heated vapor barrier as it is even at 50-60 degrees.

The way I am leaning at the moment is a new 85% efficient boiler but now with only a 2.8 gallon tank and much better boiler jacket. This should take less time to heat the overall water in my system. Considering 5-6gallons of water in my 250ft of piping. 106ft, plus runs to get there. Plus then only 2.8 gallons in the new cast iron tank.

JakeCK

Just want to add that ventless gas log sets are dangerous. I used to have one in my house until I found out how dangerous they actually are. It is now disconnected and has become a decoration in my fireplace. 

TerrS

@jakeck yes I know the risks but after 20 years with no issues, I think that risk is very low. Given I have carbon monoxide detectors in the ceiling right above the logset, plus every year I clean the whole logset and oxygen sensor. Yes it could malfunction but then so could my flue, or a multitude other things expose me to those risks.

Personally for the penny heat I get, and precautions I feel it's worth it.

But thank for for bringing that up as  concern...

pecmsg

TerrS said:

@pecmsg correct. As I have been going thru my house over the past 31 years, I have been dropping all the plaster and lath. Insulating and putting up drywall. The attic is used as storage only. So it's cold or hot depending.

It would be interesting how you calculated that savings. My issues as I see them, are I boil the ocean as it's a 6gallon cast iron tank, that I am putting 150btu burner too. 20 minutes later I am just starting to get heat it took to make 120 degree water and 10-15 more minutes for 180 degrees to really heat my house. There is probably around 2 gallon of extra water, given 80ft of 3/4" pipes volume. As it circulates it its added to the other 3 zones. So I can't see that much of a savings. Plus because of the bedrooms being right below the attic, that becomes a heated vapor barrier as it is even at 50-60 degrees.

The way I am leaning at the moment is a new 85% efficient boiler but now with only a 2.8 gallon tank and much better boiler jacket. This should take less time to heat the overall water in my system. Considering 5-6gallons of water in my 250ft of piping. 106ft, plus runs to get there. Plus then only 2.8 gallons in the new cast iron tank.

One way is to measure all the radiators length and deduct the attics %. That would give you the low ball in savings. Remember Temperature Difference in and out of the emitter affects BTU output!

Another way is use Slant Fins calculator and see how many BTU's that attic requires!

Keep in mind a small reduction is OK, larger reductions can cause issues with the boiler short cycling, you should try and avoid that.

pecmsg

TerrS said:

@jakeck yes I know the risks but after 20 years with no issues, I think that risk is very low. Given I have carbon monoxide detectors in the ceiling right above the logset, plus every year I clean the whole logset and oxygen sensor. Yes it could malfunction but then so could my flue, or a multitude other things expose me to those risks.

Personally for the penny heat I get, and precautions I feel it's worth it.

But thank for for bringing that up as  concern...

Ventless fireplaces should be avoided at all costs!
UL listed CO detectors are virtually worthless. They need to hit and exceed 70 PPM for up to 3 hours before alarming. In comparison a low level CO detector will alert at 25 PPM after 60 Secs.

TerrS

@pecmsg well my new boiler will only be a 120btu, with output of 101btu.

So 2 out of the 12 gallons total of water I am recycling. Might be 5% of total load, since the water from what I can tell looking at my boiler temperature Guage, my water only drops by 10-15 degrees max on return. Which when added to the other water, doesn't really take very long to get to 180 degrees again.

It also doesn't account for the little bit of radiant heat in the piping thruout my house as no pipe is insulated. 

So you're saying after 20 years, just throw away a perfectly fine logset, i think i have more of a concern in a 31yr old boiler. I think what everyone is also forgetting. Is 1903 house, it's not sealed tightly.

pecmsg

TerrS said:

@pecmsg So you're saying after 20 years, just throw away a perfectly fine logset, i think i have more of a concern in a 31yr old boiler. I think what everyone is also forgetting. Is 1903 house, it's not sealed tightly.

Im saying Do Not Trust your Lifewith that CO detector!

pecmsg

In the middle of the winter when it's cold and windy does the boiler cycle on and off?

TerrS

@pecmsg I would say no. I mean if the thermostat is calling for heat, the boiler will run until the water is 180 degrees or thermostat is satisfied. In calling for heat when it's 10degrees outside. Water heats to max, shuts off, cycles water until 10-15degree water temperature drop, based on aqua smart controls, boiler fires again and rinse/repeat until thermostat is satisfied.

TerrS

@pecmsg okay understand. My CO monitor gives me ppm on a display, so I can watch it. It's always Been 0 ppm so far

pecmsg

TerrS said:

@pecmsg okay understand. My CO monitor gives me ppm on a display, so I can watch it. It's always Been 0 ppm so far

With I believe a 50 PPM Minimum. 

I’m not lying. UL listed CO detectors are worthless below 70 PPM. 

Spend the money and get a Defender Low Level 

TerrS

@pecmsg I understand, I am as cautious as I can be and to get extra heat. We are in our living room around 3hrs a night, but Saturday/Sunday might be 6-7hours.  Understanding that 50 is the limit for any 8 hour period. And my dector samples every 15sec, as soon as it would possibly hit 70 and with a ceiling fan always on to keep the hot air off the ceiling. I get a lot of warm air moving around. I feel relatively safe

pecmsg

I’m done preaching!

Jamie Hall

The approach to plaster which I was thinking about had to do with actual restoration and maintenance. In restoration work, drywall or sheetrock is an absolute no-no (there really aren't very many of those, but that's one of them).

If the house has already been butchered, or will be -- trim gone or painted, floors taken up and redone with engineered, even partitions moved, that sort of thing -- then the value is gone anyway, and drywall won't hurt it that much.

A real plaster wall or ceiling is a good air and vapour barrier (not great, no, but good), is a terrific sound barrier, and is about three times the insulating value of drywall, as well as holding the warmth better. What's not to like?

The one caution: if you use modern expanded metal lathe instead of wood lathe (and I do, for larger repairs or complete walls or ceilings), be aware that it's a pretty fair radio frequency shield, so you may have some difficulty with wi-fi everywhere type applications.

Edit: I might add that plaster stands up to being soaked by condensation better than drywall does... but I will admit that drywall is a lot quicker and easier to do an acceptable job with, and takes a lot less skill.

hot_rod

The amount of water in the system is not really what drives the boiler efficiency or fuel use. Thermal lag on cold start, but also more energy available after the boiler shuts down with more water in the system

Faster ramp up on first start is all you will gain. A btu is a btu, and the amount your home needs at any given time is what dictates fuel consumption  The temperature difference between inside and outside is all it comes down to

Possibly lowering the water content could lead to more and shorter cycles, driving fuel 

on a design day, the boiler should run non stop, that would be most efficient. Right next to not running at all👩🏻‍🦱

TerrS

@hot_rod so I am no where near an expert. But keeping 8 total gallons of water heated should be less than 10-12 gallons with my current boiler. It's like a pot of water on the stove. The newer dunkirk dxl-120k is designed that way, as opposed to my current/old Pw51 boiler that's 32 years old in December.

Tom_133

TerrS, I dont know if you ever listed the boiler model (its a lot of threads to go through) but I had a customer complaining about similar things, and when I went there they were right, it was underperforming. I cleaned it well and tuned it, and I have not been back since. Thats a good starting point. If you have done that and are really wanting a new boiler, I get it. 31 years is a good go in terms of boilers. I just swapped my mothers system 2000 it was 41 years old and still chugging, but I was nervous for her.

JakeCK

TerrS said:

@hot_rod so I am no where near an expert. But keeping 8 total gallons of water heated should be less than 10-12 gallons with my current boiler. It's like a pot of water on the stove. The newer dunkirk dxl-120k is designed that way, as opposed to my current/old Pw51 boiler that's 32 years old in December.

No. The fuel use will be the same regardless of water content. 10gallons or 100 gallons will not change the fuel use in a probably sized and designed system. The difference between your pot of coffee and the boiler is that the boiler in an ideal world should be kept at a steady state dictated by the temperature difference between inside the house and the outside with a given r value of the structure. 

And this here is where you begin to see the inefficiency of having an oversized boiler where it fires hard, heats up, and then shuts down and cools off again. The same job could be accomplished with a smaller fire running continuously. Imagine driving down a country road at 45mph vs city stop and go at the same speed. My 6000lbs f150 can get into the upper 20mpgs on that country road, city is like 10.

TerrS

@Jakeck and this is another reason, if I do go the new boiler route, I am going from a 150btu/113btu to a 120btu/101btu. I sortof understand what you are saying. But assuming a 30minute or longer cycle time between a call for heat and satisfied thermostat, and yes depends on outside temperatures, means it's could be another 30 minutes, before the boiler is hot enough again to provide heat.  If I am heating less total water, that time to heat is less fuel burned. You're right that once the boiler is hot it should not take that much energy to keep it.

I did a test last year for 1 week, I installed an l8124E with a low limit, as to eliminate the cold starts.  I set it for 110 degrees low and still my 180 high. The boiler ran 4-5 times an hour about 6 minutes each time keeping the water at 110 degrees. But I had heat in less than 10 minutes. Overall my gas therms used were about 1 therm higher because the boiler cooled off and needed those 4-5 times to maintain that 110 degree water. But in that exchange I got my house warmer quicker overall

JakeCK

Not discrediting your experiment but unless you controlled for all environmental variables it is hard to draw any meaningful conclusions. The one 1 therm difference could easily be attributed to a difference in night time lows.
Over the course of a week that is less than 600btu's an hour. 

Edit: To really drive home how little energy that really is, a weekend of running my gaming PC hard could put out that much heat.

JakeCK

@Erin Holohan Haskell I occasionally get comments or edits that need to be approved. Even when there is nothing remotely questionable about it. Is that just an overzealous filter or am I doing something wrong?

Erin Holohan Haskell

JakeCK said:

@Erin Holohan Haskell I occasionally get comments or edits that need to be approved. Even when there is nothing remotely questionable about it. Is that just an overzealous filter or am I doing something wrong?

Hi @JakeCK, it's the filter. Sorry about that. If a post is edited/submitted too many times within a short period, it gets held for spam or moderation. It could also be held due to specific words or phrases. Your post above most likely got held for moderation because it includes the term "gaming" which triggers a red flag for our filters due to all the spam for online gambling, etc. Thanks for your patience!

JakeCK

Ahh got it. I'll just remember to avoid that word so I'm not wasting your time. I did edit it like four times before I noticed the message about it needing approval. :P

Hot_water_fan

if I do go the new boiler route, I am going from a 150btu/113btu to a 120btu/101btu.

@TerrS boiler inflation . 

TerrS

@Hot_water_fan yes but this post has went in many unintended directions. The other boiler possibility is a 92btu/78btu, but I think that's 2 small given my max of 88btu fins.

And the reason I am trying to stay with dunkirk is its a 2hr swap. No plumbing, gas line or electronics moves, they are all on the same side and position. It will take longer to get the old boiler out and new in than to rehook up the new boiler.

hot_rod

TerrS said:

@hot_rod so I am no where near an expert. But keeping 8 total gallons of water heated should be less than 10-12 gallons with my current boiler. It's like a pot of water on the stove. The newer dunkirk dxl-120k is designed that way, as opposed to my current/old Pw51 boiler that's 32 years old in December.

The newer boiler may have less standby loss due to better insulation, maybe a vent damper, and a smaller pot to keep warm, probably less iron thickness and weight. That should translate into a bit less energy consumption.
The 2- 4 gallon difference alone would not make a big difference in the fuel bill.

Regardless, you are making small gains all around by upgrades to the home and system, and that is the goal..

JakeCK

Do not base the size of the boiler off of the potential radiation of the baseboard. That is just the maximum they could do. As has been said by multiple people base the boiler off a proper heat loss of the house. I almost feel like it was a mistake for anyone to even mention what the baseboard can do.

TerrS

@jakeck here is my issue. Well I have many, but I have had 4 HVAC companies here for estimates. And they all proposed a 120btu boiler, only one said maybe 1 step down. Which then started this thread as I had no clue. As I stated at the beginning all stated high efficiency boilers and when I started asking about water temperature and dew point condensing. They look at me strange and " go it will work" and when I say I froze at 170 degree water in my fins. They have no response. Again this massive thread. Then in my head I am asking to quantify price over savings and ROI in years..

Hot_water_fan

@TerrS unfortunately there is not much of an incentive for an installer to correctly size a replacement, especially when it involves replacing a boiler with a smaller boiler. They don't pay the bills and the customers don't know to care about sizing, so won't pay for it. Plus, when tasked with a heat loss, their accuracy isn't great and then they own the mistake. Your heat loss is significantly smaller than 120kbtu, I think I calculated 45-50kbtu above?

JakeCK

Can you tell us more details about your house? How many square feet, ceiling height, number and condition of windows? 2x4 walls with insulation? You said it was four floors? Is that including the attic and basement? Do you know the actual dimensions of the house? For example my house is 1470sq ft of finished space on the two main floors, unfinished basement, unfinished walk up attic, 2x4 walls with very little insulation(just the kitchen and one wall of the master bed room), 5.5" of blown fiberglass in ceiling, original wood windows with storms. Prior to the new storms and foundation insulation this house could be heated at design (7f) with roughly 55k btuh and that is with a 30+ yr old 80% 115k btuh output boiler that is probably running at much less than 80%. 

TerrS

@jakeck my house is advertised as 1536sq. However my basement is 1/2 remodeled and attic is completely finished but 1950 old plaster and lath with a full compliment of probably 30ft of fin. So around 2300sq total. Much of the house has has insulation added, except for the old attic. It's storage only and never got around to working on it.  my house has all 10' ceilings except the kitchen when I remodeled I brought them to 8' to match the cabinets.

KC_Jones

TerrS said:

@jakeck here is my issue. Well I have many, but I have had 4 HVAC companies here for estimates. And they all proposed a 120btu boiler, only one said maybe 1 step down. Which then started this thread as I had no clue. As I stated at the beginning all stated high efficiency boilers and when I started asking about water temperature and dew point condensing. They look at me strange and " go it will work" and when I say I froze at 170 degree water in my fins. They have no response. Again this massive thread. Then in my head I am asking to quantify price over savings and ROI in years..

They won't do it correctly. So your choice is to resign yourself to pay someone to do something wrong, or do all the design work yourself and find someone who will install it to your spec, or as some of us did, install it yourself. I've been down this road on my steam system, I installed my own boiler. I know my job/work, and I expect anyone I pay money to, to be the same, they, in large part, are not. I've inspected enough "professional" installs in my area to know there is a lot of education needed.

TerrS said:

@jakeck my house is advertised as 1536sq. However my basement is 1/2 remodeled and attic is completely finished but 1950 old plaster and lath with a full compliment of probably 30ft of fin. So around 2300sq total. Much of the house has has insulation added, except for the old attic. It's storage only and never got around to working on it.  my house has all 10' ceilings except the kitchen when I remodeled I brought them to 8' to match the cabinets.

110k boiler will be oversized for that house. I said in a previous post you need one of the smallest, if not the smallest boiler to heat that house properly. All the statements you are making in this thread and the calculations people have been running confirm that.

The "professionals" you have had in won't even do the work (and get paid for it) that is being done in this thread for free. Heck, email them a link to this and make sure they are aware of how dissatisfied you are with the service you will be expected to pay for. And let them see what is available for free. They can't hide from it anymore.

pecmsg

Where are you located?

we might have someone near by

TerrS

@pecmsg Pittsburgh pa

TerrS

@KC_Jones thank you for your help. When I questioned the first guy, he basically told me tough xxxx in not so many words. The 2nd person did sortof heat loss calculation but because of this thread i knew he was off, when he came back with the 120btu model but he is also the one that said I might be able to step it down by one. The third guy hasn't given me a response yet, he said a week but I slammed him with all the information from this post. So he knows what I am expecting.

So I was reading everything again tonight and need one clarification or maybe I am just dense. Given that my maximum btu's I could ever output is 84600btu's.

Can you explain one more time that isn't my lowest output boiler, or something very close to it?

My heat loss calculation total  was around 18k*.78*60hdd/24 =38kbtu/hr. How does that play into my sizing? Meaning hot_water_fan said around 80k btu max boiler

So that tells me a 94k btu in /78btu out would work fine in my configuration?