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View Full Version : Thermostat: too simple a concept-a sad tale



Bassman
10-10-2007, 09:18 AM
Forgive me, I have failed in the most menial and basic DIY jobs.

The 55 yr. old thermostat went into the dumpster a few weeks ago. I bought what I thought would work from L**** and tried to install it. I have a very simple floor furnace: you put the wires together, the thing lights up and heat rises up, no fan. I gotta say, I consider myself an advanced DIYer, and have installed thermos before but I couldn't get this sucker to work. I wired every combination possible (there's only two wires). Called tech support (for a thermostat!) and got some, I'm sure, very nice woman in Delhi who I could not understand and had to hang up on her. Tried email, "what sort of unit is a floor furnace?", they ask. Floor, like the thing you walk on, I say. In the meantime the unit is being returned to the store. I want my old 1952 thermostat back, mercury and all.

So, HONEYWELL, I'll spend my 30 bucks somewhere else since I can't even get to someone who speaks English to help me out.

Rancher
10-10-2007, 09:49 AM
1. Is it just a plain old bi-metalic mechanical thermo?
2. Is it electronic and needs a battery?
3. Does it work?

Use a multi meter and check for continuity as you adjust the setting...

Rancher

Wet_Boots
10-10-2007, 09:49 AM
Maybe you need a "millivolt" thermostat for the old heating system. A newer one would be designed for running from a 24 volt transformer. Millivolt thermostats needed no power supply. See if you have a 24 VAC control transformer for the old furnace.

Bassman
10-10-2007, 01:11 PM
You folks know it all, thanks.

Rancher
1-the old one was probablyas you say
2-needed no battery
3-I'll never know, it's being returned as I type this.

Wet_Boots,
Aha! A milivolt thermostat. There is no transformer on the furnace so that means the thermostat has to be able to operate using only the mili-voltage generated by the thermocouple? I'll be sure to get one that specifies that.

abikerboy
10-11-2007, 02:59 AM
You folks know it all, thanks.

Rancher
1-the old one was probablyas you say
2-needed no battery
3-I'll never know, it's being returned as I type this.

Wet_Boots,
Aha! A milivolt thermostat. There is no transformer on the furnace so that means the thermostat has to be able to operate using only the mili-voltage generated by the thermocouple? I'll be sure to get one that specifies that.
If your floor furnace is gas and has no blower in it at all, its probably a milli-volt unit. If it's oil, or has a factory fan on a propane unit (or older nat gas unit), then it may use a standard 24 volt tstat. When you go with an electronic tstat, they are differant. Easiest wat to tell...if your furnace is not connected to your house wiring...ie...it works as usual when the power is out, its a millivolt unit. If your furnace is connected to your house wiring, and does not work without electric, then its probably 24 volt. Some electronic tstats have a switch inside that you can set for either millivolt or 24 volt systems, but all of those do use a battery at the tstat.

abikerboy
10-11-2007, 03:06 AM
"what sort of unit is a floor furnace?", they ask. Floor, like the thing you walk on, I say.
Ummm...lol...us country old timer folk know what a "floor" furnace is. 28"X38" or larger (appx) grate in the middle of one room only that if you step on barefoot, you get those painful waffle stripes and blisters on your feet that last for weeks! Bring them to america to show them!!! My mom still heats with one of those fired by fuel oil! In my single level home, small footage, yep, Id almost sell my soul for one of those old "floor" furnaces!!! Real heat, and hot heat as well! Raise the grate, and set a pan of water on the firebox for a comfortable house...Im sure you know what I mean. Anyone here know of someplace where a gun feed oil fired floor furnace can still be bought (and Im serious here)?

jimbo
10-11-2007, 06:28 AM
Generally floor furnaces are not legal anymore. I was told a few years ago by a rep from Williams furnace that they still had them available, for direct replacements, but recommended against it.

Bassman
10-11-2007, 12:36 PM
Generally floor furnaces are not legal anymore. I was told a few years ago by a rep from Williams furnace that they still had them available, for direct replacements, but recommended against it.

I can see why they are illegal now. This one is original to the house, 1952. It's not so much of an issue since I live in SoCal and hardly need to use it. It's actually a unit that has registers on back-to-back walls. If I had the $$ I'd replace it, regain the floor space and have a forced air unit installed. My house is only 1000 sq. ft. so a local pro could have it installed in time to go surfing before it gets dark.

Bassman
10-11-2007, 12:41 PM
Ummm...lol...us country old timer folk know what a "floor" furnace is. 28"X38" or larger (appx) grate in the middle of one room only that if you step on barefoot, you get those painful waffle stripes and blisters on your feet that last for weeks! Bring them to america to show them!!! My mom still heats with one of those fired by fuel oil! In my single level home, small footage, yep, Id almost sell my soul for one of those old "floor" furnaces!!! Real heat, and hot heat as well! Raise the grate, and set a pan of water on the firebox for a comfortable house...Im sure you know what I mean. Anyone here know of someplace where a gun feed oil fired floor furnace can still be bought (and Im serious here)?

A lot of these old California cottages have these. I've only seen gas-fired. It puts out real heat as you say, it just takes a while for it to make its way into the back rooms.

BTW, I bought a $10 mechanical thermostat that works just fine now. :)

clea
10-27-2008, 09:44 PM
Had the same problem with the new thermostat replacing the old mercury millivolt type. Turned out to be a pilot generator on our old 1950 45,000 BTU floor furnace. So we kept the old thermostat and we have decided to buy a new floor furnace due to a rusty heat box, we are looking at Empire Comfort Systems 5088-N , that measures 36x24, or Williams 4505622 24x32 . We love the floor furnace , we use a small quiet fan to move heat out of the hall into living room , works great! Hope this helps you.

hj
10-28-2008, 06:53 AM
A 24 volt thermostat, even a mercury bulb one, has a heat anticipator coil in it. That coil will short out, or affect a millivolt system dramatically. You want the simple "$4.95 special" which does nothing except open and close.

boser
11-30-2008, 07:25 AM
Do you mean that you replaced your thermostat and found that when the new one did not work correctly you needed to replace the pilot generator?

I seem to have a similar situation after replacing a mercury thermostat. The new unit just contains an (electronically controlled) relays, but now the furnace no longer turns on reliably when its cold. I measured the generator voltage, it's only ~400mV, I heard somewhere (???) they should be around 700mV.


Had the same problem with the new thermostat replacing the old mercury millivolt type. Turned out to be a pilot generator on our old 1950 45,000 BTU floor furnace. So we kept the old thermostat and we have decided to buy a new floor furnace due to a rusty heat box, we are looking at Empire Comfort Systems 5088-N , that measures 36x24, or Williams 4505622 24x32 . We love the floor furnace , we use a small quiet fan to move heat out of the hall into living room , works great! Hope this helps you.