Need advice on gravity furnace

PatriciaGrace

We inherited an old house with a Wards coal “octopus” gravity furnace that has been converted to gas. It is on an old mercury switch thermostat (not digital) and is run to a thermocouple booted onto a light socket in our basement. I want to know if there is a way to convert it to a thermopile so we will have no interruption in our heating during power outages. I am not interested in updating. I know the efficiency issues. We will be working on ways to mitigate those as much as possible in order to preserve the historicity of our home. 

Big Ed_4

You would need to change the gas valve , pilot assembly and controls not rated for millivolt like your limit switch and thermostat. Best to replacing all the control and thermostat wires . Don't run the thermostat wire too far under 20'

PatriciaGrace

What do you think the expense would be for those parts? I don’t know that it is very likely there’s someone in my area who works on these. I don’t think it is very common to still have them here. I don’t even know how I would go about finding someone!

PatriciaGrace

What do you think the expense would be for those parts? I don’t know that it is very likely there’s someone in my area who works on these. I don’t think it is very common to still have them here. I don’t even know how I would go about finding someone!

Big Ed_4

I could not tell you , it's against the rules to talk price here on the Wall ..

Ask around local for a price ...

SlamDunk

You can get everything you need from grainger or supplyhouse.com. You need to find someone who can do the work. They need to know what to order. Not a DIY project.

JUGHNE

A good sized UPS backup would run your gas valve a long time.
You would have to have your 24 volt transformer cord connected to do this.

Steamhead

@PatriciaGrace , where are you located? We might know someone who can help.

EBEBRATT-Ed

I am not sure it is code compliant to use a millivolt system. They are usually only used for replacement or on gas fireplaces etc and some wall heaters.

I don't think I have ever seen one on a gas power burner if that is what you have. Your better off with what @JUGHNE mentioned if you insist on not replacing the furnace

PatriciaGrace

Central Kentucky near Lexington!

PatriciaGrace

We also have gas logs that need inspection so if someone does those too, that would be a plus. Though I am also looking at chimney work and etc. and usually those also do gas logs. This house is huge. 

Tim McElwain

Yes your gravity furnace can be converted to Powerpile you will need a Honeywell VS820 Powerpile gas valve and a Q314 Pilot with a 750 millivolt pilot generator. As far as compatibility of the other controls I need to know there numbers and Make to answer that. You will also need a Powerpile thermostat.

mattmia2

It would probably be far less expensive to get a 24vac supply that can run off of a 12v lead acid battery and add a connector or switch to power it off of the battery derived supply in a power outage than to try to convert it to a milivolt system.

Either solution will only work if it is an atmospheric burner.

WMno57

mattmia2 said:

It would probably be far less expensive to get a 24vac supply that can run off of a 12v lead acid battery and add a connector or switch to power it off of the battery derived supply in a power outage than to try to convert it to a milivolt system.

Are there any gas valves and thermostats that run on DC power? I'm interested in something that would work in an off grid home. Battery banks are always DC. These are most commonly 12vdc, 24vdc, or 48vdc. An inverter can make AC from the battery bank, but there are losses. A simple elegant solution would be something that can run on DC.

PatriciaGrace

Well, the end goal is to have off-grid capability. This house is a learner for me and my husband. We intend to invest in it and practice as we go, then use the equity to buy another property that can be a farm. Rent this out and use the proceeds to pay the note. Great area for rentals here and real estate is HOT. Want to live the dream so I can go off and be left alone. You know?

PatriciaGrace

Oh! ALSO - thoughts on how to do this in such a way that it can easily be brought into solar later? The battery bank/DC power route sounds the most compatible. 

PatriciaGrace

Tim McElwain said:

Yes your gravity furnace can be converted to Powerpile you will need a Honeywell VS820 Powerpile gas valve and a Q314 Pilot with a 750 millivolt pilot generator. As far as compatibility of the other controls I need to know there numbers and Make to answer that. You will also need a Powerpile thermostat.

Allow me to introduce you to the monster in my basement! The pics are kind of in random order and include images of the thermostat wires and where the thermocouple is booted into the light socket there on the other side of the basement. The images should give you all the relevant info, though. There is one of the faceplate on the gas control box.

PatriciaGrace

Also just assume I know about any necessary asbestos abatement. We have lead paint too. Par for the course!

WMno57

If your plan is to rent this out, I would replace the octopus with heat pumps. Drop the gas service and make the house all electric.

Solar good (on your personal off-grid home). Rental income good. Solar, battery banks, and irresponsible tenants, NOT GOOD!

EBEBRATT-Ed

@PatriciaGrace

As long as you understand any money you put int the beast is money wasted.

Any fuel you pay for 1/2 of that money is going right up the chimney. It may be difficult to rent with that furnace. You could use a high efficiency furnace and cut your fuel bill in half, maybe more

mattmia2

EBEBRATT-Ed said:

@PatriciaGrace

As long as you understand any money you put int the beast is money wasted.

Any fuel you pay for 1/2 of that money is going right up the chimney. It may be difficult to rent with that furnace. You could use a high efficiency furnace and cut your fuel bill in half, maybe more

In ann arbor where I live the housing code requires heat to be included in rent if the equipment doesn't meet a certain efficiency requirement and the structure doesn't meet certain insulation requirements.

That transformer with the splice with the masking tape and all the splices right next to the transformer is for a doorbell.

Some controls have coils rated ac/dc and some contacts are rated for 24 vd or more but many are not. It is a different construction to be able to deal with both. If you are going to that expense then you might as well spend that money on making it milivolt, but the parts to do that are going to be fairly expensive, especially compared to a small inverter that can supply the 1 a or less of 24 vac that the gas vale will require. There will be some losses in the inverter, but the consumption is tiny.

pecmsg

So your going to take an Antique that 90% of techs are going to walk away from or will not return a second time and change it even further?

When something fails who are you going to call for repairs?

I love the old stuff but that old girl had a good life and owes you nothing. Replace it with a modern high efficiency unit that WILL pay for itself in the long term.

At least something that is younger then the average tech!

SlamDunk

@PatriciaGrace, we inherited a gravity furnace just like yours except it burned oil. It had age related problems- it was installed in 1905. And, during itslast heating season we burned 1400 gallons. The year before that, 1700 Gallons.

We replaced it with an oil burning, 80% efficient furnace. This year, so far from november 1 to Feb 6, we have burned 280 gallons.

I just wanted you to know how inefficient those furnaces are before you invested in it. They are beautiful in their simplicity but simply not worth it