Get clocked Challenge

GW

It was zero outside this morning. Perfect design temperatures. I took a few minutes to clock the run cycle of my heating system. I did not have time nor energy to sit and watch the gas meter outside. The boiler chugged at low capacity for a minute then slowly ramped up to high fire.

All you heating enthusiasts and wall lurkers, please imitate my data. With your own house.

model: Viessmann WB1B nat gas 
Input rating: 91,000 btu 

Burner on: 5:50 minutes/seconds 
Burner off: 4:05 minuets/seconds

Math- that total cycle is 595 seconds, 3600 seconds in an hour, that’s about 6 cycles per hour

6 x 5:50 is 35 minutes 
35/60 is .583
91k x .583 is 53,083 BTU hr
(rounded up, the boiler was not high fire that whole time)

its about a 2800 sq ft single story, well sealed and insulated (not super insulated). 

share your data 😀

hot_rod

Sounds like the boiler is oversized, in a perfect world, it should run pretty much full fire on a design day.
Seems it should at least ramp to low fire and stay there.

2800 sq feet at 20 btu/ ft would be a 56,000 BTU/ hr load at design. Cn the boiler be derated, any short cycling functions, ramp delay?

GW

Yes well it was the smallest in the viessmann line back in 2012, and now for that matter. The Tekmar and the Viessman don’t communicate extremely well with each other (no dc signal just an end switch to make heat)

 Normally the boiler runs at low fire the whole cycle. At some point I’ll go to the viessmann B2HB series. The old 200 series units were not as customizable as the new 200s, so I went with the “less smart” 100 series.  I have an 79 gallon indirect so I need a little juice when that needs some heat 

PerryHolzman

@GW

This has to be a either a control or programing issue, or both. It should just purr along at about half its full firing rate essentially most of the day. This model was designed to modulate between 37 to 91 MBtu/Hr (Input).

I have its predecessor the WB2A introduced to the USA market in 2003 - installed in 2006 that modulates just fine using the Viessmann outdoor reset and inside temperature control (which does not have any degree markings on it - and I have a wall mounted thermometer next to that controller)

As best as I can tell: My WB2A (25-91 MBtu/Hr input) boiler runs for weeks, if not months, at a time in the winter - unless I turn it off. It stays firing even when changing between Domestic Hot Water and Heating. I have been spending a lot of time in the basement this year. I'm always checking the supply/return temperatures and listening to the boiler.

Perry

Jamie Hall

For reference... it was -1 yesterday morning, with a howling wind. It took Cedric a steady two hour run (at a steady 4 ounces per square inch) to bring the house from 63 to 65, then during the rest of the day he ran for about a half hour every hour or so (2.75 gph nozzle). He's sized almost perfectly to the radiation (thank you, @Charlie from wmass !), but the radiation seems to be sized to a slightly colder design day (and, when installed (in 1930), no storm windows...). I have the original specs for the job, but they don't include the design parameters.

GW

 Perry, it’s a 100 series, you have 200 series. LOL trying to create a fun exercise everybody’s beating on my boiler. 

GW

Jamie, you’re running at about 50% as well? I think a system that runs full-time on the coldest day of the year is near folklore.

Although, i installed the boiler a couple days ago (yanked a yuge Thermopride oil beast). The little viessmann B2HB-26 was running nonstop. Drinking about a gallon an hour of propane. The thermostat finally satisfied right before I left. The house is a little leaky, so the HomeOwner and I need to talk about tightening things up. Which is already on his radar. 

Jamie Hall

Almost exactly 50% on the really tough days, @GW . And I agree -- a boiler that runs all the time on the design day is probably a myth -- and, honestly, I'm not sure I'd be real happy about that. No margin at all, and I've never been really keen on situations where I didn't have at least a little extra in reserve... and I've been in a few situations where having that little bit extra made all the difference!

PerryHolzman

GW said:

 Perry, it’s a 100 series, you have 200 series. LOL trying to create a fun exercise everybody’s beating on my boiler. 

@ GW: I'm aware of the difference between the 100 and the 200. I have the literature and technical data manual for your boiler as well. The Vitodens 100 was designed from the start to be a modulating condensing boiler, and with the right controls and programing it will work essentially like mine does (there's lots of features I don't use - I have my boiler in one of its very basic modes).

The device in my living room is not even a temperature sensor. Its a bias input (and without looking I believe there is a manual knob on the boiler control panel to do the same). Does my wife want the temperature in the house warmer, or colder. There is also a switch for normal mode (24/7) "night mode" where it allows the house to get cooler at night, vacation where it allows the house to cool off (keeps it about 55 F if I recall), or off.

I was told that if I wired a normal thermostat to "call" for heat when the room got cold that the modulating feature would not work (and perhaps the outdoor reset would not work either). My boiler works off the outdoor temperature sensor (outdoor reset) and the curve that is set in the boiler; and I can adjust the temperature of the house up or down a certain range with the bias control.

I suspect that if you disconnect your thermostat that calls for heat and set your curve and programming correctly that your boiler will operate properly in its modulating mode - with long steady firing rates when your heating load is above the minimum firing rate of the boiler, and you may well be able to add a bias control like I have. Somehow my boiler seems to understand when it needs to shut down and restart periodically during fall and spring. My wife has me adjust the bias in the late fall down, and early spring up, about 2 F. Fantastic engineering.

All the base modes in my boiler exist in yours as well.

Perry

PerryHolzman

Jamie Hall said:

Almost exactly 50% on the really tough days, @GW . And I agree -- a boiler that runs all the time on the design day is probably a myth -- and, honestly, I'm not sure I'd be real happy about that. No margin at all, and I've never been really keen on situations where I didn't have at least a little extra in reserve... and I've been in a few situations where having that little bit extra made all the difference!

Jamie: My boiler runs all the time during the winter. I'm not sure that it ever fired at 100% during design days. My gripe about "Design Days" is that in my area that is -15F; and we do see down to -30F on occasion (actual temperatures - not wind chill). So yes, you need that margin. My boiler was the smallest Vitodens model of its time - and Like GW's it has a max firing rate above my Slant Fin Calculated heat loss for the design day.

To second your point though... it sure came in handy when it got -25F several times and the one time we had -30F for several nights. I think the boiler might have been firing 100% at that point.

I'm not sure how they figure "Design Days" when historical temperature records show that for decades we often have 10 - 15 F colder temperatures than that for at least a few days each year.

Perry

bburd

In good HVAC engineering practice, heating design temperatures are usually selected so that either 97.5% or 99% of the time the outdoor temperature is expected to be higher. This is described in the ASHRAE Fundamentals Handbook. I believe Manual J and most other heat loss calculations are based on that authoritative source.

The rationale is that sizing for the lowest expected temperature would result in higher construction costs for greater system capacity that would seldom be needed, and an efficiency penalty for running a system that is oversized in most conditions. The extra cost may be minimal in a small building, but in a large one it can be quite significant.

That is how we used to do it anyway; the discussion was between the system designer and the owner.  Energy conservation codes have recently gotten very prescriptive about this. 

I think most HVAC contractors who deal with small residential buildings err on the side of never wanting a customer to call them on the coldest day of the year and complain that their house won’t come up to the set point. 

GW

Perry I tossed and turned all night and finally arm wrestled my boiler to the ground. It was a viscous battle. I lowered the outdoor reset knob to get it to run steady on low fire. Then I suited up, put my scarf on. Went to the gas meter and stuck  my iPhone into an old shoe (on top of a cooler) and filmed the gas meter for a full 2 cubic foot revolution. 190 seconds. 38,000 BTU. 

The old goat (WB1B) doesn’t have a “shift” so if I don’t turn the knob back up it won’t heat the house well in milder winter days. 

You’re tough! Not many people can get me video taping gas meters when it’s 1 degrees outside 

PerryHolzman

bburd said:

In good HVAC engineering practice, heating design temperatures are usually selected so that either 97.5% or 99% of the time the outdoor temperature is expected to be higher. This is described in the ASHRAE Fundamentals Handbook. I believe Manual J and most other heat loss calculations are based on that authoritative source.

The rationale is that sizing for the lowest expected temperature would result in higher construction costs for greater system capacity that would seldom be needed, and an efficiency penalty for running a system that is oversized in most conditions. The extra cost may be minimal in a small building, but in a large one it can be quite significant.

That is how we used to do it anyway; the discussion was between the system designer and the owner.  Energy conservation codes have recently gotten very prescriptive about this. 

I think most HVAC contractors who deal with small residential buildings err on the side of never wanting a customer to call them on the coldest day of the year and complain that their house won’t come up to the set point. 

Thanks for the information: As an engineer who has had many discussions on if we use 90%, 95%, 97.5%, 100%, 110% (or more to allow for equipment degradation); it strikes me as interesting that the HVAC engineers think that they or their wives would accept a house that did not maintain proper temperature and average of 9 days a year (which might be 9 days straight). I could have seen 99%... but 97.5%?...

That explains it. I believe you are right about heating contractors - especially where it gets really cold (having a house 15 F below normal is not going to sit well with anyone in my area).

Perry

EBEBRATT-Ed

@PerryHolzman

Your right. That's what they tell us to do. But a heat loss calculation and equipment selection are two different things.

How do you buy a boiler that has the exact out put for the calculated heat loss? You almost always have to go up to the nearest size. Also no matter what heat loss calculation is used there is always some guesstimating in it. Air infiltration and quality of construction are always variables. It's never an exact number , just a safe number

PerryHolzman

@GW: Thanks for the efforts and the picture. OK, you have verified that the low fire setting works essentially as designed (factory rating 37,000 Btu/Hr, you got 38,000 Btu/hr, which is essentially the same considering the accuracy of the method).

So then why does it not properly modulate.

Back in 2006/2007 when I was active on the forum after selecting the Vitodens 200 for my boiler someone fed me the contact name and phone number for the Viessmann head engineer in the USA, after discussing what I had been writing about on this forum. He was from Germany, and we had a very interesting long discussion about the Vitodens boilers and Viessmann in general.

The applied concept of all of the modulating condensing boilers by Viessmann by the mid 1990's in Europe was that as long as house was reasonably airtight (so wind only had at most a mild effect on heat loss) and that the radiation was properly sized for the rooms in the house; was that the required boiler output was solely a function of outdoor temperature. Hence, when the Vitodens Boilers were introduced to the USA the only active control was the outdoor reset, and the contractor then adjusted the heating curve to match the type/method of radiation and the house insulation. The bias control that I have, as I understand it, essentially allowed you to move the curve up or down a bit (without changing its shape) to fine tune house temperature.

I had to modify the selected heat curve my 1st year a bit to get it to match my house (my memory is I moved it by 1 setting). In my case - my wife is more sensitive than I to minor temperature variations and I need to adjust the bias just a bit between when the boiler fires intermittenly for days (fall and spring), and when it usually runs all the time (winter)

This engineer understood that US Contractors/homeowners largely did not understand this approach and wanted a controlling thermostat, US tapered pipe threads, and simpler controls; and they were working on that for the next generation (The 100 W and 200 W). However, Viessmann would always design its modulating condensing boilers to operate just off of outdoor reset as that was the most effective and most efficient design. His other comment that I remember was that all the complexity of individual heating zones with different possible room temperatures made things more difficult as well (and an impression I got was he thought the modern way of doing things in the USA was often needlessly complex).

I find your setting of 1 (the "A" heating curve) to be very interesting in the picture above (see your operating or system setup/maintenance manual). I do note that you say that you have to turn it up to make the house heat properly at other time. What is it normally? Do you often have to change it?

I see no reason why a selection of a higher heating curve would not allow your boiler to modulate properly and heat the house properly assuming that:
1) Your house meets the assumptions of reasonable air leakage and properly sized radiation.
2) That you have the outdoor reset temperature sensor installed properly.
3) That you do not have other temperature controls wired to the boiler that interfere with it.

Have you ever tied disconnecting your thermostat and other possible water temperature controls and just letting it run on outdoor reset and finding the proper heating curve? Disconnecting these other devices may require a change in programming (I only did a brief look at the Installation and Service Manual; for my boiler it does require changing at least 1 program setting).

Sometime simple is best... actually oftentimes (and my monoflow T cast iron baseboard is about as simple as it gets).

I wish you well with this,

Perry

GW

Perry the Tekmar controls the boiler. The 100 doesn’t have a shift. I am very familiar with European heating systems. I have a lingering feeling, you think I have a 100 simple series and don’t understand the nuances of European heating. I have a WB2A at the office/shop, I’m very familiar with it. I don’t want to blather on. 

As Ed said. Actual heat loss and boiler selection isn’t the same, unless we are taking larger homes (100,000 btu heat loss and up) 

I’m pretty Hawkish when it comes to downsizing boilers and furnaces. I have an ongoing list that I keep, of how many BTUs I drop off of this job and that job. 

PerryHolzman

@ GW: That's fine.

I'd like to point out that you started this thread with a post that identified that your boiler is cycling on/off about 6 times per hour (which I believe is considered short cycling), and that you figure that its firing at 100% when it runs (that the boiler is acting only as a simple full fire condensing boiler when it runs, which is consistent about what I was told would happen to my older Vitodens 200 if I connected a thermostat).

Then you asked for comparisons...

This on a boiler that was designed to run continuously in a modulating mode above its minimum firing rate, with decades of use like that in Europe (the Vitodens 100 predates the 200), and at least some use like that here in North America (where the installers have not disabled the modulating mode). My understanding is that the Vitodens 100 is the predominant Viessmann mod/con boiler in Europe and works in modulating mode well and also well outsells the Vitoden 200 here in North America.

It just seem strange to me that you would disable the modulating feature and accept all the wear, tear, and inefficiencies of short cycling such a boiler at 100% firing rate. The boiler is more efficient at lower firing rates.

That's your choice... I'm moving on and wish you well your your Vitoden 100's that you have.

Perry

ethicalpaul

GW said:

 Perry, it’s a 100 series, you have 200 series. LOL trying to create a fun exercise everybody’s beating on my boiler. 

You knew what you were getting yourself into

sunlight33

Just curious, how did you disable the modulating feature?

GW

Good Golly Perry I was seeing if anyone has an idea how much BTU they are actually burning on a very cold day. Most people don't have mod con boilers so I did the simple math exercise to illustrate a basic formula. I have nat gas, so I could have (should have!!!!!) just clocked the meter the first go round.

"Disable the mod feature" where did i type that?? When I use the word 'shift', you do know what I'm talking about right? And, you do know the 100 doesn't have a shift, yes? My heating system is so 'flat' (the curve)---I sincerely don't have the energy to run to the boiler every time we have a cold snap. Saving $30 in fuel in January isn't on my radar.

My exercise was to calculate actual BTU loss, but we strayed into this big boiler cycling thread. You are holding true to your engineering ways for sure.

GW

@sunlight33 we have a breakdown in communication. It's not turned off.

PC7060

@GW - Gary,  Just got my numbers for the past couple periods....

House Size: 3200SFT (excluding basement)
Construction:
Original Section (2000 SFT): 1928 with original windows, overall well insulated
Addition (1200SFT): 2020, very well insulated
Location: Northern VA
ASRAE Std. Heating Day: 15F

Period: 12/03/2020 - 02/04/2021 (63 days)
Average Temperature: 39F
Coldest Temperature: 19F

Gas Utilization:  286 Therms
~ 4.5 Therms/ Day 
~18.9KBTU hours

System Performance:
HTP UFT80 with HTP SSU40 Indirect.
BTU/HR: Modulating based on ODR
Total Run hours: 940
Total Ignition Cycles: 710
Average Boiler Run time: 80 minutes (1:20)
Average Runtime over period: 60%

Did you figure out your utilization for the total period?

I'm sure you'll find my average temperature pretty mild relative to  Northampton, MA.

GW

@PC7060 excellent stats! I didn’t figure the whole period like you did. My goal was just to figure btu an hour in the coldest days. 

Way to go! A fellow BTU nerd😀

Paul Pollets

Gary, when you turn the heat knob on the 100 past 5, will it keep up? or does the tekmar render it disabled?

GW

Paul it's a nice boiler but not very smart. I normally have the knob at 2.33 or so. When I got busted for allowing my boiler to cycle, I went and turned the knob to about 1.33 or so. Then it ran non-stop. GREAT! Then the weather got to the 30s again. I come home from work and the heating guy in me heard the geothermal system running (set at 68; the Tekmar is set to 72). I'm like wow I've got no heat on the radiant system. I go downstairs, nothing seems wrong, turn the know back to where i originally set it 8 years ago (2 1/3), and Vroom, boiler did its thing. I tried telling the engineer 6 times that it didn't have a shift, not sure if that ever sunk in. I want to throw in a 200 but don't want to buy stuff aimlessly. I could go on and on why i chose the 100 (primary loop circles the whole boiler room, was gonna set up other heating systems at some point, wanted a dumber boiler)

iced98lx

Gary this thread made my super curious. My system is a vintage 1978 Utica 250k btu boiler heating base boards. I've updated what I could in the middle of a heating season to try to keep things running well but had no way of knowing how often or how long the boiler was actually firing... until now.

We are on what I'd call "Dang near" design days right now, lows well below zero, highs also below zero. South Dakota doesn't often get more than a few days of this, so great time to see what's going on while I watch the propane tank and my wallet empty!

I fired my my smart home app of choice and started working tracking my boiler on time. An amp clamp on the wire from the Hydrostat to the gas valve gave me a nice solid reading so I can use that. I'm finally to the point where I"ve collected some useful data to share:

model: Utica 250AGB
Input rating: 250,000 btu

Number of cycles recorded: 28 (since about 3AM this morning when I finished this...)
Number of minutes of fire-on: 133
Average length of fire on: 4.75

Working on getting length between fires, setting up data by days etc but your question sparked some fun development work.

GW

@iced98lx That’s wicked cool I’m glad you have the BTU bug. Simply time one ON and one OFF cycle and we can do some math. Maybe get you a much smaller boiler if you’re able to unleash some dough 

GW

Oh- since you’ve been bitten by the bug: after you time an on off cycle. Try tuning your boiler temp down, 10 degrees at a time. See how low you can “still heat your home” 

iced98lx

GW said:

@iced98lx That’s wicked cool I’m glad you have the BTU bug. Simply time one ON and one OFF cycle and we can do some math. Maybe get you a much smaller boiler if you’re able to unleash some dough 

Oh- since you’ve been bitten by the bug: after you time an on off cycle. Try tuning your boiler temp down, 10 degrees at a time. See how low you can “still heat your home” 

The boiler is is oversized, that is for sure. Even with last night's low at -25 and today's high of -9 (exceeding design conditions by a decent margin) boiler on to off is still about 4.5-5 minutes on average. We're circulating at least 1-2 zones nearly all the time with these temperatures but yet we haven't seen a meaningful uptick in fire on time, just the same 4-5 minutes to kick it up to temp.

I have a hydrostat 3200 plus on it, and have it set to maximum number of zones settings, that has helped with the raw number of times it fires. I suspect setting maximum temperature will just cause more frequent, shorter fires, no? I guess I have the logging in place to find out!

My initial heat calculation suggested 130k was roughly what we needed, I need to do a more detailed one, I suspect even 100k might be plenty, depending on what direction we go with the water heater. One thing we're always sort of dealing with is that the house is very heavily zoned, so we have some zones as small as 100 sqft.

hot_rod

About the only type of boiler or heater that can deal with small, or micro zones like you mentioned is a tank type. Basically a boiler with a buffer built in. Even on low load days you want at least a 10 minute run time to avoid excessive cycling.

HTP had some nice tank options, starting with the Voyager, then the Phoenix, 50 gallons and modulation. I'm not sure what they have nowadays. The Polaris was another great heater for micro zoned applications. Not a lot of choices for condensing, high mass, high volume anymore.
Add a buffer tank, or Viessmann 300 might be an option.

iced98lx

hot_rod said:

About the only type of boiler or heater that can deal with small, or micro zones like you mentioned is a tank type. Basically a boiler with a buffer built in. Even on low load days you want at least a 10 minute run time to avoid excessive cycling.

HTP had some nice tank options, starting with the Voyager, then the Phoenix, 50 gallons and modulation. I'm not sure what they have nowadays. The Polaris was another great heater for micro zoned applications. Not a lot of choices for condensing, high mass, high volume anymore.
Add a buffer tank, or Viessmann 300 might be an option.

Thank HR, you've been extremely helpful in nearly every question I've had on this board, I hope you realize how much that means to a DIY homeowner like myself. I really value knowing the fundamentals of the systems operating the house, no one wants to be stranded after all.

The zone sizes do vary pretty widely from 1200sqft (two of these large single space zones, Kitchen/Living/Dinning room and the family room to the smaller end (two small bedroom+bathrooms) so I think a buffer tank of some sort may need to be part of the plan as even with a 10:1 turndown we're not going to be buying a boiler that is sized for 100-150sqft of decently insulated space.

Adding some math to my application @GW to calculate the "time between firings" as well, since that seems relevant. Here are the logs from the last few hours:



You can really see the solar gain kick in stretching the time between runs out. Keeping in mind this is temperature of -10 and wind chill of -27, so we're well below a design day.

hot_rod

Here is the formula, the math is fairly simple if you know or can estimate your multiple loads.

Voyager

I have not done the level of monitoring or experimentation that you have done, but I have been playing with the maximum boiler temperature and reset parameters. Last year was my first full year with my Triangle Tube C50s. This is heating a 32 x 48’ workshop using in-slab radiant. I initially had set the maximum boiler temp at 86 and I found that the boiler could not keep up on the days it got to zero or below. I designed for a 0 degree outside and 70 degree inside temperature delta. The work shop could not maintain 60 degrees when it was 0 or below outside and would run 53-55.

Last fall I upped the maximum boiler temp to 100. Yes, a pretty big change, but I wanted to “book end” the max temp and ensure that I had not simply miscalculated the heat load and undersized the boiler. This year the boiler has held at 65 pretty consistently, even down to 0 outside. I am running warmer this year as I have a project underway in the workshop. I have the normal lag to 63 or so at night when the temp drops outside and the slab takes time to react to the wall thermostat (no slab temp input) and then overshoot to 67 or so things warm up fast in the morning, but generally holds 65 pretty well.

I have not timed the run lengths, but the boiler seems to run quite a long time when I am in the shop and hear it kick on. It is pretty quiet and I can’t hear it if my refrigerator is running or I am using power tools, so I don’t always know when it fires and shuts down. I also have no way to know if it is modulating. I find nothing in the manual in regard to a way to display that and an email to Triangle Tube tech support confirmed that you need “special software” to see that and only their engineering department has that and they would not make it available. I can’t believe they don’t provide a way to confirm that modulation is occurring. You can run a low fire and high fire diagnostic test, but I have listed to the boiler carefully and I can’t hear any obvious noise changes during a firing cycle as though the burner was modulating, but then it is an extremely quite boiler and the noise difference between low and high fire may be less than my old ears can detect.

I sure would like to know what the firing rate is in real-time and, better yet, what their modulation algorithm is, but Triangle Tube seem unwilling to share either.

JR3_Home_Performance

A Laars boiler I installed recently allows many parameter modifications. One of them is max firing rate. Between that and the turbomax reverse indirect it doesn’t short cycle on baseboard. I have it programmed such that heat calls open up corresponding zone valves and turn on the system circulator. Only the buffer tank calls to the boiler itself. On short heat calls the boiler isn’t activated. I have the tank setup for about a 25F differential I believe. Also the boilers max target output temp is about 5-10F over the buffer tanks high limit. I think last I left it the tank swings between 120-145 with a boiler target of 150 or 155. 

JR3_Home_Performance

At my own home I run a 110kbtu triangle tube with an external (taco) outdoor reset control. It’s a victorian era 3200sqft duplex with cast iron radiators. The energy modeling heat loss calculations put me at about 55kbtu. I added up the EDR one day and came up with a projected reset curve needed. I figured a max water temp of 140 at -15 I think. That was pretty conservative it turns out. I’ve dialed the reset back several times and think I finally found the limits. A max water temp of 105F will let the downstairs apartment have about a constant heat call 20-24hrs/day according to nest. They set the heat to 70 and it hasn’t dropped below 69. Talk about minimizing temperature swings. Unfortunately I get some minor temperature swings upstairs due to a lower heat load and lower thermostat set point. I think with a little more tweaking on the low side of the chart (higher outdoor temps) and I can get it fully dialed in. With these low water temps and a delta T circulator the boiler will always condense. I have the boiler set to a target of 150F I think but I don’t believe it ever hits that. Basically it runs flat out when it gets called. I have no short cycling either. That is due to not only the radiator and pipe mass but also the 500 gallon custom unpressurized buffer tank. The boiler seems to run for at least 45 minutes when it kicks on and it only runs a few times per day. The buffer tank also has a pex coil running through it to preheat my domestic. A self contained heat pump water heater does the final domestic finishing. With 4 adults and 2 showers I haven’t noticed any issues with capacity even though the water heater is locked out from using electric resistance back up

GW

@Voyager yes maybe pull the cover off? You should be able to hear the high and the low, it's quite noticeable with the cover off. I may have read too fast- LP or natural? If nat gas you can simply look at the meter. Plus, most boilers have a 'tachometer' of sorts that displays the level that the gas valve/combustion is operating at. I don't have any familiarity with your boiler brand.

GW

@JR3_Home_Performance yes with all that mass you're gonna have nice long cycles. Obviously in mild weather it's not going to do a long cycle, but all that water and metal makes thing run for sure.

The thread kinda drifted early on into a 'cycling' thread, the general idea was to get people looking at their actual BTU on a very cold day by either observing on vs off cycle in an hour or simply watching the gas meter.

GW

also @Voyager not many people drop their stat setting at night with radiant, I don't touch mine at work or at home. Let it rip 24/7.

Voyager

GW said:

@Voyager yes maybe pull the cover off? You should be able to hear the high and the low, it's quite noticeable with the cover off. I may have read too fast- LP or natural? If nat gas you can simply look at the meter. Plus, most boilers have a 'tachometer' of sorts that displays the level that the gas valve/combustion is operating at. I don't have any familiarity with your boiler brand.

Yes, might be more detectable with the cover off. The CC50 is a quiet unit though. I have NG, but the meter is 150’ away on my house. I had the gas line run to my workshop from my house downstream of the meter so I don’t have to pay two basic monthly charges. Given that my house is all gas with three furnaces, a water heater, dryer and stove that all use gas, it is hard to catch a time in the winter when the workshop boiler is the only thing running.

The CC50 uses very little gas. I literally have seen no detectable increase in my gas bill since I started heating the workshop. The month to month, winter to winter, and gas price variations swamp out the CC50 usage. It must be using $20-30 a month, but I doubt much more than that.

Voyager

GW said:

also @Voyager not many people drop their stat setting at night with radiant, I don't touch mine at work or at home. Let it rip 24/7.

I don’t drop mine at night either. It is set to 65 all the time. The temp at the thermostat will swing down to 63 on a cold night and often overshoot to 67 in the morning when things warm up. You just can’t overcome the physics of a 5” x 32’ x 48’ slab of concrete when the outside air temp is varying 30 degrees day to night.

GW

ahhh I misunderstood, so if the place is dropping, then you nailed it- you need more heat. I didn't catch that.