Power back-up for electronic ignition on a boiler?

AlysonReed

When we lost electricity last winter during a severe snow/wind storm, the electronic ignition on our gas boiler (Burnham) would not work. We ended up with frozen pipes due to loss of heat. I contacted U.S. Boiler today to inquire about whether there is a solution, such as a battery-powered back-up for the igniter, or a way to plug the boiler into a generator so it could power the electronic ignition, but use the gas line for heat. They said a flat no, expressed no interest in developing a solution, and referred me to exactly no where. This seems like a common problem that could be easily solved, but I have no technical expertise, so perhaps I am missing something. Please advise. Thanks.

Jamie Hall

It is easily solved. But it depends on whether you also have any fans or blowers. If you have no fans or blowers, in most cases a simple (but fairly large capacity) UPS such as is used for computers will do the job very nicely. Just wire it so it is supplied from the mains, and the ignition is supplied from the UPS -- just like you would your computer. It will carry an hour or two.

However, if you have fans or blowers, that won't work, and you'll need to install a backup generator for your house (which isn't such a bad idea anyway). Most of the better ones supply clean power which should do just fine. They must be installed in accordance with local code, including at the very least an approved transfer switch.

Jamie Hall

PS. Make that fans, blowers or pumps -- two places.

vr608

Jamie Hall said:

PS. Make that fans, blowers or pumps -- two places.

Is this just due to the load requirements, or some other reason?

SteamedInWharton

I'm surprised there's no inline COTS solution for this. It won't take much to power the spark, damper motor, Tstat, LWCO, and various sensors. The only serious load would be during startup. It may be due to the popularity of hot water and hot air over steam which require power for pumps and fans.

I mean you could take a small computer UPS and do a bootleg hookup but there's no low-cost existing product that would pass code and meet UL standards. But the bootleg hook up won't necessarily have an interlock. To me using a computer UPS would be the same as going to the store and asking for the male-male plug (suicide cord) to connect your generator to a dryer outlet without using a transfer switch or listed interlock kit.

I have seen some products listed as "inline" UPSs that were for IT equipment, but they're pricey.

Hmmm, I wonder what this is for:
http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=UTSHW&ISOCountryCode=US&gclid=CNaly-7V48gCFUyPHwodyXII6Q

Abracadabra

vr608 said:

Jamie Hall said:

PS. Make that fans, blowers or pumps -- two places.

Is this just due to the load requirements, or some other reason?

Yes. You can run fans/blowers/pumps off battery backup, it's just that the amount of batteries you'd need would be substantial in order to have more than a few minutes of runtime. And there aren't (m)any UPS's that are cost effective for a residential heat system. If you are interested in also running fans/blowers/pumps on a backup system, I'd recommend installing a backup generator.

SWEI

The problem is that North American systems have been built around a 24 VAC power supply since at least WWII. Batteries don't store AC, so you need an inverter or a UPS. There are a couple of 24 VAC inverters out there, but they are spendy and somewhat hard to come by.

Newer systems have DC internals, and many of them actually supply DC to the thermostat (ask me how I know this.) There might be hope, but it is a ways off.

Jamie Hall

I may have unintentionally created some confusion. I do NOT recommend trying to run a boiler -- or anything else, for that matter -- off a cheap UPS. Unless the unit is fully certified (UL and CSA, at least) I wouldn't go near it. The minimum level of equipment I would suggest would be something like this:
http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=BR1500G&total_watts=200

That assumes that all you are powering is a natural draught gas boiler and its controls. It won't do for oil. It won't do for hot water or forced air, never mind a heat pump. For any of those you need a generator -- and, as I said, it must be properly installed according to code.

SWEI

Sealed combustion systems also draw more -- typically somewhere around 80-100 Watts on the few I have measured.

Remember that a typical computer UPS is designed to provide a relatively high amount of power for a relatively short time (often just 15 minutes at full power.) Drawing a smaller amount of power will make the batteries last longer, but you really have to look closely at the runtime charts. Take the number they show and divide it in half, then use that to decide if you have enough battery to hold you through a typical storm.

BobC

If you need something to run a boiler for days it costs less to buy a good generator than a comparable UPS. By the time you are done it could cost half the cost of a boiler replacement to do it to code.

It can be done for a lot less if you ignore code but if you get caught your screwed. makes you wish you had a good old millivolt boiler.

Bob

Jamie Hall

BobC said:

If you need something to run a boiler for days it costs less to buy a good generator than a comparable UPS. By the time you are done it could cost half the cost of a boiler replacement to do it to code.

It can be done for a lot less if you ignore code but if you get caught your screwed. makes you wish you had a good old millivolt boiler.

Bob

True. Unless you are running a farm in the country, and then, my friend, a good solid generator with the proper wiring and switches is worth its weight in gold. Ask me how I know! I take very good care of that baby indeed.

AlysonReed

Thank you everyone for these answers. I do not know whether the boiler has any fans, blowers or pumps. It is used to generate steam for a 1930s era radiator system. The hot water heater is powered by electricity. It seems like the back-up generator is more viable than the battery-powered UPS. Our neighbor has a large capacity generator (stationary and external to the house). During the storm, he offered to let us "plug-in" to it to power our electronic ignition, but the boiler does not have a plug. Should we just hire an electrician to address this or is it more complicated than that? Please forgive my lack of technical knowledge.

vaporvac

Perhaps you could post a pic of the boiler?

Jamie Hall

Alyson --

A back-up generator is the way to go, in my opinion. It isn't complicated, although to do it right isn't inexpensive, either. Unless you yourself are knowledgeable about electricity, the best way to do it is to hire a competent electrician to do the job. That said, there are two approaches. One is to have a permanently connected unit, such as I imagine your neighbour's is. Another is to have a unit which can be plugged in to your house when you need it. Either way, the house must have a generator transfer switch. This switch serves to disconnect your house from the power company's lines and then to connect your generator (or your generator's input plug) to the house. You can power your whole house, or you can select which circuits within the house will be transferred.

Sizing the generator isn't hard; figure out what items in the house you want to run on the generator (I don't recommend the electric water heater -- they take a lot of power) and add up the power demand from them -- so and so many watts. Add a margin, and there you are. Your electrician should be able to do this accurately for you -- but it's never a bad idea to have done it yourself, just to double check!

There's also the question of fuel for the generator. If you have natural or LP gas available, that's probably the best. Ordinary gasoline is also fine, but can be a bit cantankerous to start in cold weather. Diesel is wonderful -- but diesel generators are very expensive indeed, and require preheat to start when they are cold (cold being below about 15, Fahrenheit, depending on the engine).

AlysonReed

Vaporvac: I'll post a picture and also look for the model # etc.

MikeG

Jamie isn't part of the issue with generators and electronics the clean power aspect? We all agree the battery UPS don't have enough power to run much. Wouldn't running the electronics from the UPS powered by the generator at least clean up the sine wave, or does that require a special UPS? I have a generator, and a Munchkin boiler. Never had to find out if it works with my generator. I know there was a long thread about this in the past. Mike

Jamie Hall

Depends on the generator, Mike. Some of them produce pretty clean power. Some of them... not so much. My old Generac (try almost 20 years old!) runs everything just fine, but your mileage may vary, as they say. And yes, running the power through a UPS or even just a good quality line filter such as is sometimes used for very high fidelity sound systems would help, if the electronic gremlins are fussy.

SWEI

Really old boilers will run on pretty much anything that resembles 120 VAC. Somewhat older (say 10-20 years) units with onboard electronics (similar to your Munchkin) can be rather picky about waveform details.

Really cheap generators (the $300-$800 big box store variety) tend to have poor load regulation and may also have waveform issues, particularly when connected to modern electronics.

Depending on the UPS design, it may or may not clean up (or make worse) whatever comes out of the generator.

boosey

Using a generator and a extension cord
I installed a 30amp 2 pole knife switch the wire from the furnace goes to the middle of the switch. When the switch is in the right position it is connected to utility service and is not connected to the generator when the switch is in the left position it is connected to the generator and not the utility. But you need some who knows how. The best way is a transfer switch. Go on youtube and search generators DIY transfer switch.

JUGHNE

What I have done for people who have a limited capacity generator and don't /won't install a transfer switch is to make the heating equipment (boiler or furnace) cord connected. Just wire it as a free standing appliance as if it were a Refg etc.

For the furnace/boiler I put a 3' 14 gauge power cord, like that for the dishwasher, on the unit. Replace the power disconnect
switch on the unit with a standard outlet, preferably a GFCI type as this is probably in the basement. The outlet and cord must have no connection other than the green ground connection. The power cord serves as the power disconnect for service of the unit.

Put your generator outside and run into the basement a good #12 AWG 3 wire extension cord......don't go cheap on this.

You can run your heating as needed, maybe the sump pump to avoid flooding, in some cases a 120 volt water pump. Then another cord upstairs for the Refg and freezer. Depending upon the size of generator how much load you can apply. Plug in lamps are good for both floors.

But the homeowner has to be aware of his generator limitations.
Also his own..........people in the rural areas of the Midwest are accustomed to lack of power on occasion. In our house we actually have kerosene lanterns filled for the event. In the office I have 3 to 4 fair sized UPS's for computers etc. and have a small desk lamp with CFL installed.

Keep the generator outside or you may make the News.

Henry

After our 23 days without power ice storm of 1998, I was on the committee to find ways to keep natural gas apliances functionning during power outages. We looked at everything from wind power, solar photovolcaik panels etc.. The perfect solution was a 12 Kw natural gas generator with automatic switching.

MikeSpeed6030

I have a 1,000-W, pure sinewave, 12-V dc to 120-VAC inverter. I can run it off my car's 12-V battery/generator. I have things pre-wired to easily (and safely) run an extension cord to supply my gas-fired boiler, including the circulator pump. During an extended electrical outage, and if the car starts running out of fuel, fill it up at a gas station still in operation. Much simpler and less expensive than a standby, emergency engine-generator.

A potential problem with an engine-generator is getting it started, particularly if it is manual, recoil start. And then the engine needs to exercised frequently and the fuel kept fresh.

Jamie Hall

I'm not really keen on plug and play for fixed appliances -- like a boiler. For an appliance which is designed and listed for that use -- such as a washing machine or a refrigerator or freezer or even an electric stove -- no real problem. For a fixed appliace, though... For one thing, it may not meet code, and a building inspector might be perturbed. More to the point, however, is grounding. By using the plug and play option, one has lifted the ground connection to the boiler, and it is quite possible that the boiler -- and any piping connected to it -- will be at a different voltage from the rest of the plumbing. Or, for that matter, a damp concrete floor. This could be a shocking experience... (been there, done that!).

vibert_c

@Jamie Hall At the time of the shocking experience was your outdoor generator grounded with a ground rod?

Jamie Hall

I was 16 at the time... many many decades ago... and not in charge. It was a useful learning experience. But no, it wasn't, in answer to your question.

The only approved way that I know of to connect a generator to a system (let's leave out the portable appliances for the moment) is to ensure that it is fully grounded -- to the same ground array as the rest of the system. Multiple ground arrays are not approved by code, for good reason. This isn't rocket science: your connector from the generator to the building system goes through a transfer switch -- break before make. For a 220 volt system, both hots (red or black) are broken in the switch. The neutral (white) is not broken. The ground, which should be an independent wire (green), is also not broken. There are situations, particularly for farm work, where it is permissible for the neutral to also serve as the ground tie to a remote breaker box, such as might be found in a barn.

JUGHNE

Jamie, with the method I use, the furnace cabinet is fully grounded/bonded to the house grounding electrode system because the bare/green grounding wire is left intact.
Inspector wise (sometimes that is a contradiction in terms ) our AHJ allows dishwashers and garbage disposals to be cord connected and after hearing the reasoning for the heating system cord connect will allow that also.

Jamie Hall

@JUGHNE -- you have a more intelligent AHJ than some out there...

SWEI

The general rule is that if the appliance listing includes a cord and plug you are OK. Retrofits are not generally permitted, but the AHJ can always make an exception.

JUGHNE

The common sense for the GD and DW is that the appliance repair person can change these out with out tampering with the house wiring. The outlet for both is under the kitchen sink and services as a handy visible disconnect for troubleshooting. One major city I used to wire in wanted the DW hard wired, the CB was the only disconnect then, PITA and not so safe to troubleshoot while running.

One new subject is garage door openers, resi ones have cord, (don't try to put a longer one on....rough in the outlet correctly). But commercial door openers are hard wired. No cords allowed, (today anyway).