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How efficient is my boiler? No really
So a number of formulas to use to get to efficiency, steady state, the condition where boilers are rated.
Cycle efficiency as boilers do not always, probably seldomly run at steady state.
Run cycle, how many and how long the boiler cycles.
Numbers are probably close to what you see in of oversized boiler installations. Maybe 80% of residential fixed output boilers??
If you have equipment to collect some date, enter your own numbers.
Thanks to Siggy for the formulas and number crunching.
First slide shows cycle efficiency using different boiler rating numbers. Shows run fraction with a 10 minute run time. To the right a 60K load on a 100K boiler at a 40 day. Design of 70°inside 0° outdoor. 15,000 Btu/hr. internal gains, 4.8 KW.
The second slide shows a 150K boiler on a design load 100K application.
20,000 btu/hr. internal gains is everything inside the home adding heat, people appliances, lights, computers, so about 6KW.
A fixed output boiler in a zoned application will see these operating conditions, run fraction for example.
Cycle efficiency as boilers do not always, probably seldomly run at steady state.
Run cycle, how many and how long the boiler cycles.
Numbers are probably close to what you see in of oversized boiler installations. Maybe 80% of residential fixed output boilers??
If you have equipment to collect some date, enter your own numbers.
Thanks to Siggy for the formulas and number crunching.
First slide shows cycle efficiency using different boiler rating numbers. Shows run fraction with a 10 minute run time. To the right a 60K load on a 100K boiler at a 40 day. Design of 70°inside 0° outdoor. 15,000 Btu/hr. internal gains, 4.8 KW.
The second slide shows a 150K boiler on a design load 100K application.
20,000 btu/hr. internal gains is everything inside the home adding heat, people appliances, lights, computers, so about 6KW.
A fixed output boiler in a zoned application will see these operating conditions, run fraction for example.
hot_rod
6
Re: Will converting my heat from steam (boiler) to electric baseboard heat freeze my pipes?
Quite true. And even for a modern house well built and well insulated the figures that are quoted for those strip heaters are wildly optimistic.Square footage is nowhere near an accurate way to determine heating load, especially in an older building not built to modern standards for insulation and air tightness. The actual load has more to do with that and the climate than with square footage.emaydeoh said:@bburd yes just confirmed with our repair man they are running 240v! They are on their own 30w circuit breakers. I honestly think it's just too small for the space. Theres a 6ft one in the living room that is rated for up to 200sq ft of warmth, but the room is probably about 300sq ft and open to the kitchen, so about 500sf total...
Re: New Steam boiler; higher pressure on pressuretrol
@pmj My approach would be to keep the boiler repipe with a 5” drop header, install a 2 stage gas valve triggered by a vaporstat.
EzzyT
3
Re: Simplified Radiant Cooling
I see a need for a control like this as a2whp become more popular. Quite a few variations in Germany where radiant cooling panels are more common.
Rehau has done a handful of large radiant ceiling jobs, I suspect the building automation watches dew point somehow. There were a few radiant panel products at AHR for radiant cooling ceiling installations
Taco has chilled beams at their building in a humid RI climate, maybe they will share the control used.
Head over to the ISH show in Frankfurt next week, I’ll bet you would see many controls like you are considering.🧐
Rehau has done a handful of large radiant ceiling jobs, I suspect the building automation watches dew point somehow. There were a few radiant panel products at AHR for radiant cooling ceiling installations
Taco has chilled beams at their building in a humid RI climate, maybe they will share the control used.
Head over to the ISH show in Frankfurt next week, I’ll bet you would see many controls like you are considering.🧐
hot_rod
1
Re: Installer has let new cast iron boiler condense for months.
The only way a bypass could be set is for one condition. That would be all zones open and at design condition. Setting that valve on a mild day with no load on the radiators will not be accurate, as the return blending with bypass will be higher..
If the boiler at design cannot get up over140 or so SWT, there is no way that bypass can increase the boiler operating condition. Thermal equalibrium, the mass of the system is in charge, not the aquastat on the boiler.
And as zones open and close that bypass mix will change as it cannot respond to varying loads.
If it is worth repiping it is worth doing it correctly
If the boiler at design cannot get up over140 or so SWT, there is no way that bypass can increase the boiler operating condition. Thermal equalibrium, the mass of the system is in charge, not the aquastat on the boiler.
And as zones open and close that bypass mix will change as it cannot respond to varying loads.
If it is worth repiping it is worth doing it correctly
hot_rod
2
Re: Draining sediment from my indirect fire tank
Ever had your water tested?the hardness and TDS has a lot to do with thebuild up in any tank that is heater. High temperature coils from the boiler water can also scale.
It takes some pressure and turbulence to flush heavy sediment. Just opening a drain may not do much.
It takes some pressure and turbulence to flush heavy sediment. Just opening a drain may not do much.
hot_rod
1
Re: Will converting my heat from steam (boiler) to electric baseboard heat freeze my pipes?
@dabrakeman yes the electrical baseboard heaters are being installed as we speak. I have reached out to someone from this forum who was recommended to me and lives in Denver to see if there is any last attempt to just fix the steam heat on my own. I don't have a lot of money and don't feel super hopeful it is something I can afford on my own though. My "landlord" is a family member who is letting me live here for cheap before he tears the house down, so I don't have a lot of leverage as a "tenant", also no lease agreement, etc.
emaydeoh
1
Re: Tankless limitations/ workarounds?
Vermont is one of 4 states that require mixing valves on all DHW sources. If this is a customers residence, best have one both for code compliance and liability.
No question they need maintenance depending on water hardness. Valve around it knowing this.
To get much output from the coil inside, you may need to maintain the tank at 140 or higher. That coil is designed for 180 f or higher SWT for indirect use. Pulling heat out, the opposite way will take some delta T, depending on what you expect for btu/ hr on the radiant? The only way to increase that output would be raising tank temperature, since your flow is limited by the tankless circulator.
No question they need maintenance depending on water hardness. Valve around it knowing this.
To get much output from the coil inside, you may need to maintain the tank at 140 or higher. That coil is designed for 180 f or higher SWT for indirect use. Pulling heat out, the opposite way will take some delta T, depending on what you expect for btu/ hr on the radiant? The only way to increase that output would be raising tank temperature, since your flow is limited by the tankless circulator.
hot_rod
2
Re: Navien combi units
What are your DHW demands? Storage-tank type water heaters will give you a buffer when a lot of hot water is being used. Combi units will typically only give you around 3gpm of untempered hot water which will let you shower and do the dishes at the same time, but any more than that and you will run into trouble.
Navien's seem to have a good reputation and good tech. support.
Navien's seem to have a good reputation and good tech. support.
Re: 2 year old boiler issues
I spent thousands on a 5 year labor, parts, and service warranty. Unfortunately if they can’t fix it, I will need to find a new company.clammy said:Fire them they are clue less . Even after re piping it’s still wrong . You need some one to repipe your boiler properly in steel and w a properly sized header ,equilizer and Hartford loop aside from usually updating main venting . As for cleaning that boiler they’re just lazy ,those side outlets boiler as the easiest to wand and flush and skim it sheer laziness stopping them . I high doubt skimming and cleaning alone will drastically improve your performance . The supply take off of the equilizer is garbage and is a sign of not knowing much about how to pipe a steam boiler and connect its mains properly to a header , not brain surgery . Check the find a pro listings on this site and possibly if you’re lucky some one is near and can give you a price to correct it all and get your system operating properly . Peace and good luck clammy
MJACK
2