Can gas fired steam heat work in a power outage?

Zipper13

Last winter we lost power for two days.

We had no heat during this outage and our old home chills quickly! But we did have plenty of hot water from our separate water heater tank. My casual understanding is that the pilot in the water heater keeps enough charge for the water heater gas valve to power itself.

Got me wondering, since steam heat is mostly passive, can the same be done for our boiler?
I think the only electricity needed is the for opening the gas valve and the flue damper. The thermostat has a AA battery backups built in.

Our Burnham boiler has a pilot too.
Is there a straightforward (for a pro) swap out or upgrade that would give us enough power for heat in a blackout?
Figured I'd ask here before calling around and asking a potentially dumb question.

JUGHNE

A fair sized UPS supply could operate your boiler for some length of time..IMO.

Jamie Hall

Some older gas fired boilers have gas valves which are powered by a thermopile heated by the pilot. They require no power to operate -- but they are obsolete.

However, as @JUGHNE notes, even modern gas fired boilers take very little power, and even a modestly sized UPS can run them for hours. For longer runs, one can use an inverter from a storage battery which, depending on the battery, could run them for days.

Assuming, that is, that you have an atmospheric boiler. If it's power vented -- dependent on a fan -- they take a good deal more power.

Even a relatively small generator, however, can power a power vented boiler -- or an oil fired boiler -- with no trouble at all.

JohnNY

After Hurricane Sandy, I had several customers fit their steam boilers with extension cords and plug them into cheap power inverters in their cars' power ports.
Can we still call them cigarette lighters?

ttekushan_3

@JohnNY that’s a great idea. I used a ups once in a building where I rented but it’s limited in duration. But the inverter’s a great workaround for rare but terrible events. 

But what’s a power port? 😆

mattmia2

The bigger the inverter the more power it will use without any load at all. Your best bet is probably a small inveerter and a battery.

In addition to the milivolt systems that @Jamie Hall described, some older gas valves had a manual knob to open them in a power outrage.

Lard

12vdc to 24vac inverters exist and would be more efficient than stepping 12vdc up to 120vac, then down to 24vac at the transformer.  I have thought about getting one to drive the gas valve in my gravity furnasty through a dpdt switch and appropriate fuse at the transformer. I am sure a 7Ah 12V VRLA battery would run it for quite a while.

a simple search Comes up with some options, such as this one which is even pure sine: https://www.powerstream.com/inv-12dc-24vac/


there is also a 24vac UPS option: https://www.powerstream.com/24vac-battery-backup/

ChrisJ

JohnNY said:

After Hurricane Sandy, I had several customers fit their steam boilers with extension cords and plug them into cheap power inverters in their cars' power ports.
Can we still call them cigarette lighters?

No we can't, because most are only rated for 10amps, 15 at the most and no heat so they would be destroyed by plugging a lighter into them. That's why they're called power ports etc.

Has nothing to do with politics.

mattmia2

I have seen plenty of lighters that came with the lighter in them that were fused at 5-10 a.

Depending on how the valve is wound, you could run a simple gas valve with mechanical safeties off 24vdc. You could also run a lot of control boards off of 24vdc as well since the first thing many do is rectify the 24vac to 24vdc and regulate it down to 3.33, 5, or 12v dc.

Dan_NJ

I had an inlet installed on the boiler circuit years ago after having to rig up an auto jump starter battery to the then 24VDC transformer I had in order to get heat during a winter power outage.  Now I keep an AGM battery on float charge all the time, and an inverter on hand if needed.  I've used it two or three times over the years. I guess it's safer than millivolt system and it works OK.

ethicalpaul

JohnNY said:

After Hurricane Sandy, I had several customers fit their steam boilers with extension cords and plug them into cheap power inverters in their cars' power ports.
Can we still call them cigarette lighters?

I wanted to wire mine up this way and I still might (or I'll just do it the next time I have a power outage), but I feared to do it before I got my inspection done. I assume the inspector wouldn't look kindly on my boiler having a plug

JUGHNE

Out here in the rural area, For heating systems I would replace the disconnect switch with an outlet (GFCI).
The heater would then have a cord coming out of the bottom of the box. The heater would be connected as if it were any other cord connected appliance.
Only the green/bare conductors would be all connected together......total of 3 wires.
No other wires would be cross connected.

A UPS could then be plugged into the new outlet and the heater plugged into the UPS. This gives added surge protection for the heater.
Also if you run a generator with questionable "clean" power the UPS would clean it up.

There is some question of codes ets, however here the AHJ would not red flag it.

mattmia2

Usually the appliance is technically listed only for permanent wiring methods. I don't really see that being a practical issue as long as the ground is still bonded directly to the appliance. It would be up to the AJH if they would accept it or not. I would use a twist lock plug and receptacle to discourage anyone from plugging anything else in to that receptacle. Many mod con boilers come with a cord and plug.

JUGHNE

Every heating unit I install, I install a GFCI outlet (on the same circuit) with the disconnect switch in a 2 gang box on the unit.
That outlet is not switched and used for cond pump, work light etc.
So I would have no worry about other uses for the outlet.

PMJ

I think it is worth it to just face up to installing a transfer switch main panel and a permanent 240V extension cord to that to plug to a decent sized portable generator. The panel makes it impossible to have the generator connected to the utility when the power comes back on so anyone can switch it safely. You just wheel the portable outside the garage, start and plug it up, then throw the switches. Then anything in the house runs - just not all at the same time.

I did this years ago and never regretted it. Lots of tall trees here. Not lots of problems but a few big ones. Lots of downed wires take days to put back up. This setup has made all the difference.

PerryHolzman

Yes, you can setup a UPS for any boiler and get at least several hours of run time. I have a UPS system with extra batteries that will provide an estimated 1 week of run time for my mid 2000's Vitoden 200 + a Taco 007-F5 system circ pump with continuous operation assuming new batteries in the UPS and battery packs, and half a week with old batteries that are in need of replacement.

You can buy UPS's that allow you to add (plug in) extra battery packs. I highly suggest those. Ensure that the UPS has enough capacity to easily meet the startup load for your boiler and all pumps and solenoid valves (which is higher than the running load); then add additional battery packs to extend the run time.

Note that some UPSs only allow 1 extra battery pack, others that I am aware of allow up to 4 or 6 extra battery packs.

Another thing to be aware of; is how well the UPS protects your equipment from spikes (which kills circuit boards and controls over time - if not instantly for a bad spike) and what kind of waveform it produces.

Lower cost UPS's actually have very poor spike protection and output close to a pure square waveform. A square waveform usually shortens the life of the downstream components.

The highest quality UPS's convert all the AC into a DC voltage to use and charge the battery and have very robust spike protection; and then reconvert the DC voltage into a pure sine waveform output (matching the ideal AC volt waveform of normal line power). These are called "Double Conversion, Pure Sign Wave output" UPS's.

You can often find used UPS equipment for a fraction of the cost of new (do an internet search for "used ups"). Pick a known long term brand that makes industrial UPS equipment - and you likely have UPSs that will last for decades as long as you change the batteries every 4-5 years (I purchased used industrial Liebert GTX series double conversion pure sign wave equipment over a decade ago). They will typically come with new batteries installed when you purchase used UPS equipment from most vendors.

Note batteries cost can be noticeable. I just dropped about $1300 into new batteries and shipping for my boiler, main office computer/accessories, and medical equipment (3 @ 4 batteries each = 12 batteries) with a total of 6 additional battery packs (6 @ 8 batteries each = 48 batteries) after 5 years (60 batteries total). It also took about 2 days to change that many batteries in the 3 UPSs and 6 battery packs. Note you need to pay attention to quality of batteries. Low quality = low cost and the batteries typically have significantly shorter life (say 2.5 - 3 years instead of 5 years).

I've still got to reconnect my boiler battery pack system. I pulled a back muscle as I was finishing changing batteries and those additional battery packs weigh 75 Lb each. I put off lifting them into location for a bit (feeling better now and expect to finish this week).

I wish you the best with this,

Perry

Jamie Hall

PMJ said:

I think it is worth it to just face up to installing a transfer switch main panel and a permanent 240V extension cord to that to plug to a decent sized portable generator. The panel makes it impossible to have the generator connected to the utility when the power comes back on so anyone can switch it safely. You just wheel the portable outside the garage, start and plug it up, then throw the switches. Then anything in the house runs - just not all at the same time.

I did this years ago and never regretted it. Lots of tall trees here. Not lots of problems but a few big ones. Lots of downed wires take days to put back up. This setup has made all the difference.

For once in our lives, I'm with you 100%, @PMJ ! And the newer inverter type generators are clean power -- and inexpensive and quiet. Ample capacity for a house. The convenience and safety -- for all concerned -- make up for the fact that they aren't free...

PMJ

100% @Jamie Hall - I'll have to put this in a frame on the wall.

Doing this is not nothing because utility needs to pull the meter and all. A tree fell on the feed to my house so when they were out doing that I got a panel and they installed that for me at the same time they were fixing the main.

The safety is really a big deal. I was in the Far East on business during the big northeast blackout. I had left detailed instructions on the panel and my wife got the generator going on her own. I wanted that to be possible without worrying about it.

Worth every penny.

mattmia2

Most panelboards have an accessory to install an interlock and backfed breaker to add an interlocked separately derived source to the panelboard with minimal rework. That would not require pulling the meter.

PMJ

mattmia2 said:

Most panelboards have an accessory to install an interlock and backfed breaker to add an interlocked separately derived source to the panelboard with minimal rework. That would not require pulling the meter.

Quite true. The completed panels you buy have permanent riveted sliding plates controlling operation of the breakers so you literally can't screw it up. But for someone who knows what he is doing the bolt on solution is quite acceptable and much less expensive.

Zipper13

Great info as always. Thanks!

I think I was picturing a simple swap out with a thermopile (thanks Jamie, that's the word I was looking for) but since those aren't used anymore I guess this is a question more for an electrician.

I've thought of looking into a switch to accommodate a portable generator - for at least some lighting and to save what's in the fridge. I just assumed that it would be dramatically cheaper to find a solution to power only the boiler, but a quick Googling suggests that installing a transfer switch might not be as pricey as I thought! If the estimates I'm seeing are accurate, it seems like a good upgrade for us this winter!

Jamie Hall

It is, @Zipper13 -- as those of us who have them know! One 24 hour power outage powering your freezer can save the cost of installation... and, as @PMJ noted, the whole operation of getting it going is dead simple, once it's installed. Not sure my ex could handle it, but my daughter surely can!

PerryHolzman

For long term outages a switch arrangement and a portable generator works if you are home.

I used to travel a lot - and expect to to again. I'm often away from the house for several days, and up to a week.

The UPS with battery backup is automatic and requires no one to be home and do anything.

Ultimately, I would also like to add the portable generator option as well (as well as a backup half BTU electric boiler to keep the house and pipes from freezing if the Vitoden 200 breaks down again when It cannot be easily fixed in a few hours).

It's on my "wish" list of electrical changes to do; and also requires I get a portable generator and keep it in good enough shape to easily start (and have my neighbor start if I'm away from home).

I'm aware of a permanent natural gas backup generator with an auto "household - or partial household" switch. That's a possibility too.

Perry

Jamie Hall

@PerryHolzman , you hit -- possibly inadvertently -- on one of the key things to make a backup generator work: you have to make sure that it does, in fact work, and the only way to do that is to maintain it. At the very least, start the beast and run it under load until it is thoroughly warm. They are, too often, stuck in the back of the garage and then, when you need it... crickets.

The automatic ones are good, but they too need to be started and run under load regularly. The better ones do that. The most reliable seem to be the natural gas ones -- simply because they start more easily. However, if you pay attention to them, both diesel and gasoline work perfectly well (and, may I point out, the diesel ones run on the same fuel as your oil burning boiler, should you have one, and it's even legal to do so!).

mattmia2

PerryHolzman said:

Ultimately, I would also like to add the portable generator option as well (as well as a backup half BTU electric boiler to keep the house and pipes from freezing if the Vitoden 200 breaks down again when It cannot be easily fixed in a few hours).

A more practical option might be a small, inexpensive modcon in parallel like an HTP UFT (unless your Viessman is oil). If you can get one with big enough elements an electric water heater is also a possibility. It will last nearly forever filled with system water instead of potable water. If it is piped primary-secondary either one could just be another item in the boiler loop.

Chris_L

Those of us with "obsolete" millivolt steam systems feel lucky when we lose power in the winter.

If you don't want to go to the trouble of adding back-up power, and can deal with a partially heated house, you might consider a gas fireplace. You can get them with millivolt gas valves that don't need supplemental power.

Jamie Hall

Those millivolt gas fireplaces are really nice, I must admit. And they do work in a power failure -- although the fan won't if they have that option. They can keep a small room quite cozy.

On the backup electric water heater -- keep in mind that that's great if the problem is the boiler turning paws up, but will soak up a huge fraction of a generator's power in the event of a power failure.

PerryHolzman

@mattmia2: I'd go with an electric boiler vs natural gas for simplicity and long life. I don't need to stock parts for or maintain a 2nd gas boiler - nor route another supply and vent (no good way to do that). An electric boiler would be long life with low cost parts to keep in stock; and compact on the wall.

@Jamie Hall: I'm aware of the electric power requirements.

My fantasy is to install a 225 Amp service (I believe the original was an 80 Amp fuse box, now 100 Amp Breaker box), rewire and fully insulate the entire house (I have electric stove and cloths dryer), run a 60 Amp breaker panel to the stand alone garage, add the electric boiler backup (likely 80 amp 240V), add mini-splits to air condition the house in the summer - after tearing out the old chimney running up the center, add a natural gas auto-start backup generator, etc. I just need to win Publishers Clearing House and a couple years to do it all.

Its a good dream... 1st step is the 225 Amp service with the proper switch box for an auto start generator.

Jamie Hall

Publishers Clearing House or the lottery would be nice... Cedric's home started out much like yours, but acquired a 200 amp/240 volt main panel. It would be nice to have 3 phase for the shop -- but the nearest 3 phase is 2 and a half miles either way.

The wiring is rather interesting, however.... it was all done over in 1955, beautifully done at the time. That got it the 200 amp main panel. Since then it has acquired an assortment of sub panels, some rather better done than others -- but still all fuses, except one panel for a new kitchen and a new panel for an art studio. At some point in there a 200 amp outside breaker got added, when a new digital meter was installed. Some one of these days I'll get to a new panel (60 amp like yours) for the shop and barn, but for the time being...