battery backup

nicholas bonham-carter

when we had our new steam boiler installed, we needed by code for it to be on a separate circuit, with a couple of kill switches, next to exit doors.

we had also had a number of unexplained power outages in the neighborhood.

i just choose the biggest battery backup/ups i could find, at reasonable cost, [1500 va], and got the electrician to wire it in. it plugs into an outlet on that circuit, and the rest of that circuit plugs into it. there is some sort of isolation switch so that the boiler can still be energised, if there is a problem with the ups. the ground wire is constant, and not running only through the ups. i have not tested it completely, but the panel on the ups seems to indicate a lot of hours of use available, as i have no auto-fill, only the atmospheric burner control circuitry.

ironically, we have not had a single power cut since i set this up!--nbc

Dave in QCA

Fantastic!

That is great information... and another reason to get rid of my condensate pump!

Thanks!

The Steam Whisperer (Formerly Boilerpro)

One of the beauties of steam......

is little or no power usage for operation.  It makes it very easy to run during power outages.  It also boosts the relative efficiency of steam boiler when compared to power hungry hot air furnaces.  If my rough numbers are correct, an 80% efficiency steam boiler uses about the same overall energy as a typical  88% efficent hot air furnace, not taking into account the extra heat loss a hot air system adds to a building.

Dave in QCA

millivolt - powerpile?

Boiler Pro,



Do you know if anyone is producing a boiler today that uses the old millivolt powerpile?  In a system where no power is required at all, and if a mechanical thermostat is used, it would work great with no connection to AC power.

The Steam Whisperer (Formerly Boilerpro)

Powerpile.....

I do not think they are  legal for standard production today due to the need for dual gas valves to meet regulations.  However, I understand they are available to  the Amish.   Millivolt gas valves are still made, so probably the thing to do is to install a second millivost generator and and two millivolt gas valves in series.  I never tried this yet, but I hope to someday.  Timmie would probably know the rules for this type of installation

haaljo

80 to 88% $ound$ right.....

A ten percent efficiency gain from 80 to 88%

2000 therms used in heating season at 80%

1800 therms used at 88%

200 therms saved x 100K btu/therm = 20 x10(6) = 20 million  Btus

One horsepower blower motor approximatley 1kW x 4000 hour heating season x 25% on-time = 1000 kWh/heating season x 3,412/btus/kwh = 3 million Btus

So, (based on one hp blower at 1000 hours/year) it appear to increase steam efficiecny numbers by about one percent.

However, electicity is more expensive than natural gas.

Not having the above blower motor will save $150/year in electricity costs in the Boston area. So, the monetary efficiency is pretty close to an 8% increase.

I remember when the gas company was pushing gas absorption chillers but did not include electric loads. The electric company would have seminars on the subject of "Parasitic Loads" and ream the gas company. It was pretty funny beacause electricity was so expensive it really hurt the gas absorption numbers but it was the electric company that sent you the bill for the parasitic loads. - I enjoyed the incongruity.

Now one company owns both electric and natural gas lines here in Boston area so no more of that stuff.

haaljo

Does the UPS have 1500 kVa of batteries?

It may be that it can handle a 1500 watt load (100% power factor) for a moderate amount of time but to handle a 1500 watt load for one hour would be 1500 watts of batteries. That's a lot of batteries and the electrician equivalent of the deadmen told me that "battieries suck."

It's a good idea for momentary outages but you may have less back up time than you think and battery maintenance is a pain. I bought an inverter at Costco a couple of years ago. It was like 50 bucks. It can handle over a kW load. Enough for me to watch television and have some lights OR to run my boiler which (has a power burner) which takes a supring amount of juice. Can't do both at the same time.

I'll buy a small generator so wll even be able to run fridge but won't do that unitl After the next hurricane :-)

Intersting thread

kristoferjon

would like boiler to work when power goes out

Hi - Not a pro here, but I live in an old home with a gravity hot water system...old gas boiler in basement, radiators throughout the house. There is no circulating pump, and I believe the only components that would require AC power are the hardwired thermostat and the millivolt thermocouple. It would be great to have the system remain operational if we were to loose power. Or at a minimum, be able to manually turn the boiler on and off to heat the house. I'm having someone from a HVAC company come out tomorrow to look into putting in a battery powered thermostat. What eles would I need for this to work?

Any thoughts or suggestions would be greatly appreciated.

Thanks

nicholas bonham-carter

can boiler run with power off?

if your boiler is old enough, you may have the type of gas valve which uses no power-a millivolt or powerpile. in that case the old mercury thermostat will work fine.

as temperature setbacks sometimes do not save any money, maybe all you need is the old style thermostat anyway.--nbc 

kristoferjon

can boiler run with power off?

thanks for the reply nicholas. i do still have the old mercury thermostat on the wall, but don't think it's still connected. the gas valve does have a millivolt.

kristoferjon

can boiler run with power off?

just had the HVAC tecnician look at my system...says I would still need AC power (such as a generator during power outtages - which they are trying to sell me) to operate the 24v gas valve. still doesn't make sense to me why this could not be wired to have a simple switch to open the valve or work off of a battery.

rcrit

damper

You need juice to open and close the damper too, right?

kristoferjon

boiler with no AC power?

there is no damper to open.

doing some more research, it may be possible to wire the system to a plug/receptacle. if the power goes out, plug into a power inverter connected to a battery. i think the boiler and thermostat are on the same circuit with a 24v transformer.

could this work?

oldsteam

Boiler pump question

A friend says he knows how to operate our old boiler system with radiators in each room...without the pump if the electricity goes off.That doesn't sound like a good idea to me...could someone help me out with this--I don't want the boiler to get ruined.

ansky

Battery powered thermostat

I never really thought about this topic until I started reading these posts.  I have a steam boiler that operates via a battery operated thermostat.  Does the boiler igniter run via electricity or by the battery power from the thermostat?  My area is not prone to power outages so I don't think I have ever encountered this situation.

Jamie Hall

It's all a matter of load...

the major difference between a UPS and a battery and inverter set up is that the UPS floats on the line at all times.  Not only does it supply backup power if the lights go out, but it also filters the incoming electricity, eliminating voltage surges, voltage dips (brownouts), and various forms of electrical hash.  A battery and inverter set up won't do that.  The UPS is very useful if you are in an area where the power is "grubby" -- subject to spikes, noise, brownouts, surges, etc.



Now will it run your boiler?  If you are fortunate to have a millivolt gas system, and gravity circulation, yes.  Otherwise, not for long.  How long depends entirely on the load -- whether it is a battery/inverter or a UPS.  Add up -- or measure -- the current taken by your system when it is operating, multiply by 120 (system voltage) and that is the watt demand of your system.  The voltampere load is usually pretty close to that (depends on the kind of motors used).  That, plus the ampere-hour or voltampere hour capacity of your system will tell you how long you can run.

Ed2

power consumption

What is the reason for needing a lot of power for a gas fired steam boiler (not circulating hot water)? After a day without heat, I started thinking about backup systems and found this discussion, so I'm trying to understand.

Jamie Hall

Depends on a number of factors

Ed2 -- the power required to run a boiler depends on a number of factors.  Virtually all boilers and burners made today (in North America) require 120v single phase 60 hz power -- but they make different uses of it.  Some gas fired boilers which operate without induced or forced draught fans use the power only for control.  These can run quite some time on a UPS or batteries, as the current draw for the controls is relatively small.  However, some gas fired boilers use induced or forced draught fans, and all oil burners have both forced draught fans and oil pumps.  These use quite a bit of power, and thus pretty well require a generator for backup.



Some older gas fired boilers used "millivolt" controls (these are still available in some special situations) which used no outside power at all, but they lack many of the control features of more modern equipment.

kristoferjon

seems like it could work

My system runs off of millivolt with a transformer to 24v. I don't see why I couldn't wire the power to a plug that is normally in a receptacle. When power goies out, plug into an inverter connected to a deep cycle battery.

Ed2

thanks

Jamie- thanks for the answer. I was thinking in terms of gas, no fan. So, that explains it. It seems we would be in good shape for battery backup if we can meet the input requirements.

davevarga

Steam boiler - backup power

I have a natural gas steam boiler as well  and was thinking about backup power.  Like what happens in the dead of winter and you are at work and the electric gets cut off? 

It's 110v from the breaker box @ a constant .2 amp (that's point 2 amp), whether the boiler is fired on or off.  That goes into the input of the 24 v transformer.  24 AC output of the xsformer powers the thermostat, low water sensor and high pressure sensor. It also powers the electro relay thing for the natural gas.  My amp clamp tells me that most of the power is going to feed that relay.

OK, 110V @ .2 amp is 22 watts.'

So I have been thinking of installing a computer UPS so that it auto turns on should the electric get cut off, and turns off should the power come back on.   The 110v from the breaker box feeds the UPS and the output of the UPS feeds the input to the 24v transformer. To eliminate issues with cheap UPS's I figure I will use a pure sinewave UPS to approximate the line voltage (plus transformers only want to see sinewaves, otherwise they heat up and it is problematic). That eliminates the square wave form and stepped sine wave UPS units.  I checked out APC and cyberpower so far, pure sine wave units.

Even if I get a 1000 VA unit, if the power goes out, the 22 watt drain on the UPS will only leave me with a few hours of power. I was hoping for a full day or even more.



Any suggestions?

Jean-David Beyer

I have no suggestion, but would like an answer.

"Even if I get a 1000 VA unit, if the power goes out, the 22 watt drain

on the UPS will only leave me with a few hours of power. I was hoping

for a full day or even more."



Do not kid yourself about the run time.



1.) At low loads, the efficiency of these units is less that at moderate to high loads. So if that 1000 VA unit can run 30 minutes with a 500 watt load, it does not follow that it can run 300 minutes with a 50 watt load or 3000 minutes with a 5 watt load.



2.) If your power is as bad as mine (not really too bad), you can expect APC batteries to lose capacity, and be down to about half capacity in around 3 years. Around 3 1/2 years I have been replacing mine because after 3 years, the predicted runtime drops rather quickly. I tried for 4 years once, and did not make it. I had to resort to extreme measures to get the (swollen) batteries out.



Do not wait for the Replace Battery light ot come on. By then you have only a few days to replace them, and their runtime is only a minute or so, when new it can be 10 minutes to an hour, depending on how oversized your unit is.

davevarga

more on UPS for boiler power backup

I read what you say with great interest, just trying to get to figuring out a solution for backup power.  I am away from the house for a long stretch each day and have pets in the house.  Yep, got what you said about battery life.  All this starts gettin spensive.

About the decreasing efficiency of delivering power through the UPS.  Now this is from APC, and they advertise low power hi efficiency, and it is more than what I want to pay. However the efficiency actually goes up, the lower the power draw. Look at the graph at the bottom on the URL below on this particular unit.  675 watts = 6 minutes.  75 watts = 132 minutes.  In this example the efficiency increases 250% approx. at the 75 watts compared to the 675 watts.

http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=SUA1000JB&total_watts=50

Jean-David Beyer

I was thinking of much lower loads.

I have an APC Smart-UPS 620. (No longer a current product.) I originally bought it for a small computer I no longer have. When I got Verizon's FiOS, it comes with a box on the side of the house that converts the fiber-optic signal to 4 voice telephone channels (I use only one), a TV channel (I do not have TV) and an ethernet connection for my computer(s). This has a small power supply inside my house that  only uses 5 watts or so. It has a small UPS built in. I do not know if that UPS has an inverter in it or not; it may just supply the DC that the box on the side of the house requires. But that UPS does not run very long, and if the power fails, it cuts off the ethernet and the TV to save power. This so as to prolong my ability to dial 911 as long as possible.



Since I had the spare 600 VA UPS anyway, I plugged the FiOS power supply into that and it does pick up the load when the power fails. But sometimes the power here fails for a long time (4 days is the record). Since I cannot find the curve for that one, I looked up the 750 VA current model. Note that the current models are more efficient than the Smart-UPS 620 I have. It is claimed to run about 12 minutes at 300 watts and 32 minutes at 150 watts. I have no reason to doubt that. Furthermore, at 75 watts it claims 70 minutes. At the bottom of the curve, at 50 watts, 103 minutes.



http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=SMT750&total_watts=50



For the unit most like my little one, the efficiency curve is maximum at 100% load (97.9%) and it slowly drops to 94.6% at 25% at the bottom of their table. I bet is is lower at 2.5% load. At some point, such as at no load, the efficiency must drop to 0% as the thing is running, using power to overcome the inefficiency of the UPS and delivering no power to the load.



The thing I noticed is that at around 5 watts, I do not get 1030 minutes (17 hours), but closer to 8 hours. Now I may not be being fair to the unit. I do replace the battery in there every few years, but it may have been 3 or so years old when the power failed for 4 days. And running that test is boring, so I never pulled the plug on the unit a few days after installing a new battery. Perhaps I will next time, but that will not be for a while.



But thinking about it, if I wanted to power a 7 1/2 watt night light, a big UPS might not be the way to go. Perhaps I should get an LED  and power it off a car battery with DC.



By the way, and this is of no importance to this discussion, your link refers to a 100 volt UPS. I believe these are used in Japan, not USA. Mine are all 120 volt units because I am in USA.

BobC

Limited run time

I retired from USPS where I worked as a technician (after my real job went to China). We used the APC Smart UPS 1500 on some of the machines to protect the computers (3ea dual processor servers) and they proved out to be reliable for the 8 years I ran that area. A replacement set of 4ea 12v gel cells ran about $70 if you shopped around some.



I don't think that 1,500VA unit would run your 22w load for more than 6 hours (3 hours for the 750VA model)but you could lengthen that by just plugging in the load when you needed heat - IF you were home to do that.



So it looks like it would work fine for relatively short power losses but not for one lasting days. I like the idea of using dual powerpiles but even that would only work for atmospheric equipment without motorized dampers.



Bob

haaljo

Experience with inverter during recent outage

I had good luck using an inverter off my car battery during last storm. It was 600 watts.

Dave in QCA

such a quandary

On one hand, I lean toward the simplest means of operating a steam boiler without electrical power, a millivolt system.  It would work great on an atmospheric.  However, when I consider the efficiency advantages of a power burner, wet base design, along with the fact that they appear to be more resistive to the dreaded water line rot, millivolt systems and UPS power supplies wouldn't help much.   Also, given the fact that the real concern isn't with being without heat for an hour or two, but rather a day or two, the benefits of a standby generator begin to have merit.  After all, heat being off for 2 hours would barely be noticeable. 

A standby generator can also protect against food loss in your refrigerator or freezer.  That can certainly add up to a hefty figure.  Plus, you can have lights, TV, etc.   If the power outage happens in the summer, I sure would like to have the benefits of some A/C too!  I appreciate my comfort in the sultry, damp, and humid spells that we have in the Midwest.  The market has become saturated with these units and the price has really dropped.

So, when I come back to really weighing my options, I WILL scrap my condensate return pump, but will go the route of a power burner wet-base boiler.   UPS won't help me, so I'll be looking at nat gas fired generator options too.  

We love our machines, don't we!

haaljo

600 watt inverter

$100 at Costco. It ran the boiler controls/vent damper, A 20" TV, and two laptops with cellphones acting as modem (Android app called "PDAnet"). That was in recent blizzard./outage in Boston area. I was using about a quarter gallon of gas an hour. No fridge but if I needed AC could have just sat in car.

First power outage in a half dozen years. Took an hour to set it all up about an hour after we are all settled in - power came back but could have gone for a few days.

davevarga

More on back up power for steam boiler in case of power outage

Thanks to JDB, BobC, haaljo, Dave in QCA ... your input is greatly appreciated!!!

I am really not looking for back up power for refrig, a/c.  Just back up power for worst case scenario - the steam boiler furnace should the power fail during the winter, and backup for at least one day.  And chances are I will not be at home, so I do not want to turn on a back up generator.  UPS might be a prime candidate for a solution, I am thinking..  Maybe I am hoping for too much.  By the way, it appears the thermo electro device for the gas is consuming almost all of the 22 watts of power.

Dave in QCA... what do you mean by millivolt system, atmospheric and Power burner and wet base design? And what is a power-pile?

 On one hand, I lean toward the simplest means of operating a steam boiler without electrical power, a millivolt system. It would work great on an atmospheric. However, when I consider the efficiency advantages of a power burner, wet base design, along with the fact that they appear to be more resistive to the dreaded water line rot, millivolt systems and UPS power supplies wouldn't help much. Also, given the fact that the real concern isn't with being without heat for an hour or two, but rather a day or two, the benefits of a standby generator begin to have merit. After all, heat being off for 2 hours would barely be noticeable



Best,

Dave

Dave in QCA

powerpile

A powerpile and millivolt system are used in the same system.  A powerpile is a pilot light device that generates a very small voltage, a millivoltage, much the same as a thermocouple, but it is a little bit larger.  The millivolt power, generated by the power pile is used to operate the millivolt gas valve.  The millivolt circuitry is ran through the rest of the safety devices, such as low water cut off, high pressure cut off, etc.  This sytem requires no connection to regular a.c. power.  These are apparently no longer manufactured or offered as standard equipment.



An atmostpheric burner is a standard gas burner that utilizes and orifice, air shutter, and burner.  These can be round burners like on a stove top, or ribbon burners, like most hot air furnaces and most boilers today.  see this link to Weil McLain LGB series. http://weil-mclain.com/en/multimedia-library/pdf/weil-mclain-pdf/products/boilers/commercial-boilers/lgb/lgb_lit.pdf 



A wet base boiler is arranged in a manner that the cast iron sections which contain the water, circle down below the fire area.  The burner and fire area is down through the middle.  This requires the use of a power burner that uses a blower moter that blower the air and gas mixture into the combustion area of the boiler.  See this link for the Weil McLain 80 series boiler  http://weil-mclain.com/en/multimedia-library/pdf/weil-mclain-pdf/products/boilers/commercial-boilers/80/80_lit.pdf     



Hope this helps you understand the equipment.

roadk

how to add the UPS...

So, I too have a similar steam boiler situation and wondered how to best get a UPS into my system.

My dedicated boiler circuit leads to a junction box near my boiler which feeds the 24v transformer. Couldn't I convert the junction into an outlet, and convert add a male plug onto the transformer , then plug the UPS into that new outlet and the transformer into the UPS?

Thanks for the help...