T87 thermostat

DanHolohan

Do you miss it? Got any good stories about it?

HomerJSmith

It had a modern look, curves were in, angles were out. Trends change to keep people excited.

EdTheHeaterMan

I found this on one of my last boiler replacement jobs before I retired. The home owner did not let me take it. He was 90 and he said his father installed it. This looks like a kit you may find in the back pages of Popular Mechanics

What was so fascinating was the spring on the little motor that acts as a worm gear to move the temperature setting from day temperature to night setback. It looks like a spring from a ball point pen.

DanHolohan

What a great find!

Illinoisfarmer

Miss it? No. I never got to touch it. I don't remember a time growing up when I was allowed to adjust that thing. It was a mystery to me. They had no problem letting me do all kinds of dangerous things at a young age, but the round golden thermostat, located in the hallway, was ONLY to be adjusted by one of the parents. This was non-negotiable. We knew dad had mellowed when years later, he told my brother "It's warm in here, would you go turn the thermostat down a little?". My brother stared at me like he'd been shot.

When I got an apartment in college, it had the same thermostat. I thought 'great, I'm in control of the heat and air conditioning'. Nope. Turns out the then girlfriend and I were, as she explained years later when she took a lot of my money, most of my self-esteem and what little pride I had left, "thermally incompatible". There were (many) other reasons for her leaving, but that one was my favorite.

So no, Dan, I don't miss it. I lived within a few feet of one for the majority of my life, but any memory of interaction with said T87s is not pleasant.

BDR529

No stories because they worked,for 40+ years!

However, when they outlawed the T-87 it was replaced with a liquid that looked like curdled mercury for a short time. That didn't work.

DanHolohan

@Illinoisfarmer, that’s a great story. Thermally incomparable and Pickles all in one post. Gosh! Thanks. 

DanHolohan

@BDR529, I wonder what that liquid was. Hmm. 

Jamie Hall

Miss it? How can you miss something you still use? There are four of them around here, all in use. They do exactly what they are supposed to do, when they are supposed to, need no fuss. What's not to like?

DanHolohan

How long do you think they’ve been there, @Jamie Hall?

Jamie Hall

Three of them are fairly recent -- from 5 to 20 years. The fourth, the main one... hmm... 60 years? Or maybe more? 70? I seem to remember it replaced an old one with a mechanical bimetal, but at that age I wasn't paying that much attention to the heat...

DanHolohan

Impressive! Thanks. 

Tinman

I guess this could have happened with any thermostat but…

In the early 80’s, I was given a service call for no cooling and we just had a different tech there earlier that day to replace the thermostat. Homeowner asked for a different guy, said the first one seemed “off” a bit. 

First thing I do is walk over to the stat and there it was, plain as day, the inverted word Honeywell. The other guy mounted the T87F upside down which means the sub base was also mounted upside down. You have to be out of your mind to do that. I don’t remember how I explained that to the customer other than the guy screwed up in a big way. 

After every call, we had to call in on the radio to report the status of the call we just finished and to get the next one. 

Me: The thermostat was mounted upside down. I spun it 180 degrees and it’s good to go. 

Boss: What do you mean the thermostat was mounted upside down? 

Me: Exactly what I said, word for word. 

The other guy gets called back to the shop and there’s alcohol on his breath. They check his van, and there’s a cooler of Old Style beer between the seats, the empty cans just thrown in the back. I believe that was his last day. Turns out, he was out of his mind. 

DanHolohan

Crazy. 

GW

Jamie I have more but I kinda bent a rule on that bit of commerce, whuups

jad3675

You know, 50 years from now there won't be a conversation like this about Nest thermostats...

My parents still have a 87 in their house - it was there when they bought it in '85. They replaced the converted-to-gas coal octopus, but my Dad didn't want to get rid of the thermostat. They only replaced that replacement furnace last year and still kept the 87. And they still don't have central AC.

SlamDunk

I have one still in use since 1950 in the house we inherited from my in laws. I believe there are a couple more in the basement. FIL was a furniture factory maintenance man. Nothing was thrown away......NOTHING!!!!

EdTheHeaterMan

This is what I was looking for before i found that old T87 add on clock
The F P Young Company had a class that was taught to anyone in the industry who wanted to retain oil heat accounts and make money replacing oil burners with modern efficient flame retention burners. We called them "Complete Modernization" of the existing heating boiler. It was usually about 1/2 the cost of a new gas boiler by our plumber competition. The Federal Gov. was paying The FP Young Co to offer a class that took 5 days to teach other oil heat dealers our sales pitch and how to install a "Complete Modernization"

The job included a Flame Retention burner (Before that we installed Lynn Burners with the Shell Head Design), A new combustion chamber, new flue pipe (Never call it smoke pipe), New Barometric draft regulator, new oil filter, and all new controls. This was the page in the sales book that covered "All New Controls" because this would replace the old thermostat and it was the only control the homeowner would touch

I remember taking that course with about 9 other guys from oil companies from New England, Chicago and Baltimore. This went on in the 1970s during the OIL Embargo/shortage/price increases. Frank Young was a pioneer in selling "Clean Oil Heat" and was willing to help the retail oil industry retain customers by conserving energy and reducing waste. His theory was "If you show a customer how to use less oil, you will sell a little less but retain a good customer." The alternative is for the customer to switch to gas and you will never sell another drop of oil to them ever again. Less is actually More!

I think this picture is a nice sales piece.

Steamhead

EdTheHeaterMan said:

....... "If you show a customer how to use less oil, you will sell a little less but retain a good customer." The alternative is for the customer to switch to gas and you will never sell another drop of oil to them ever again. Less is actually More!

From what I've seen in this area, that fell on deaf ears.

JakeCK

I had one in my house when I bought it. Got a free lux t-stat when I had an energy audit. I kept the old 87. It's still sitting on a shelf in the basement. Just in case I need it for some reason. 

DanHolohan

Thanks for those memories, Ed. Brings me back. 

reggi

Jamie Hall said:

Three of them are fairly recent -- from 5 to 20 years. The fourth, the main one... hmm... 60 years? Or maybe more? 70? I seem to remember it replaced an old one with a mechanical bimetal, but at that age I wasn't paying that much attention to the heat...

Those old Bi-Metals as the original Minneapolis or Honeywell were really majestic on the wall of any home.. 
We're they no longer compatible once modernization evolved or was it the building of a better mouse trap??  
I'd bet it wouldn't be that difficult to retrofit one of those with basic thermostat innards..via silver bulb era .. but I'm probably just letting my imagination run off.. it would be done by now if there was a reason. ..it would be cool though 

Erin Holohan Haskell

In honor of the T87:

Jamie Hall

The bi-metals had two problems which the mercury bulb units solved. The worst was that with time the contracts would become damaged in various ways -- despite that at least in the better ones they were silver plated -- and operation could become erratic. The other was that they depended on a relatively short bi-metal element, and a somewhat problematic arrangement for anticipation, with the result that they were none too precise. The mercury bulb concept was -- and remains -- revolutionary: that is a partially vacuum sealed bulb, and the liquid mercury wets the terminals without wear or oxidation. The switching action remains reliable for hundreds of thousands of cycles (it's limited by fatigue in the connecting wires). Further, with a calibrated weight of mercury in the bulb, the dead band between on and off is entirely predictable, and dependent on the spring properties. In a thermostat, that spring is the bi-metals sensing coil, and can be quite long and have quite predictable properties.

The only realistic down side is that, like mercury switch vapourstats, the thermostat has to be carefully levelled (right side up!) to be accurate. Sloppy workmanship will not do. The unrealistic down side is that somehow the general public became terrified of mercury, and the mercury switch got banned.

mattmia2

I think the environmental problem had more to do with the manufacturing.

You could make a t-stat with contacts with a coiled bimetal strip instead of a straight strip.

ChrisJ

Jamie Hall said:

The bi-metals had two problems which the mercury bulb units solved. The worst was that with time the contracts would become damaged in various ways -- despite that at least in the better ones they were silver plated -- and operation could become erratic. The other was that they depended on a relatively short bi-metal element, and a somewhat problematic arrangement for anticipation, with the result that they were none too precise. The mercury bulb concept was -- and remains -- revolutionary: that is a partially vacuum sealed bulb, and the liquid mercury wets the terminals without wear or oxidation. The switching action remains reliable for hundreds of thousands of cycles (it's limited by fatigue in the connecting wires). Further, with a calibrated weight of mercury in the bulb, the dead band between on and off is entirely predictable, and dependent on the spring properties. In a thermostat, that spring is the bi-metals sensing coil, and can be quite long and have quite predictable properties.

The only realistic down side is that, like mercury switch vapourstats, the thermostat has to be carefully levelled (right side up!) to be accurate. Sloppy workmanship will not do. The unrealistic down side is that somehow the general public became terrified of mercury, and the mercury switch got banned.

One of the best mechanical thermostat's I've seen uses copper bellows attached to a copper capillary tube filled with a refrigerant. The bellows pushes on an arm which snaps open or closed a pair of contacts.

They seem to last almost forever, certainly longer than ant T87 so far but, they do have an issue with the contacts slowly eroding which the mercury did not. Of course, these contacts are connected to an inductive load with a start current of 12A.

I suppose the next thing would be how small of a temperature variation could such a design be engineered to operate around. The ones I have are designed around 10 degrees which will not work for a home thermostat but I would have to assume this could be easily changed in the design. Although it seems like some will tolerate their home going from 60-70F I personally like a 0.5F+- swing.

reggi

Thanks...I did't want to go Off Topic but you answered my question.. for basic needs and some variables with set temperatures those old ones could still be used (Most modest expectations) ty

RayWohlfarth

I have two stories.
I used to have a customer that referred to his heating system as the Honeywell Heating System even though he had a Weil McLain boiler.

I sold a boiler and new thermostat to an engineer and he used to time the heating and off cycles. He was retired. He made me replace the thermostat with a t87 because he said it affected the heating cycles.
Ray

EdTheHeaterMan

RayWohlfarth said:

I have two stories.
I used to have a customer that referred to his heating system as the Honeywell Heating System even though he had a Weil McLain boiler.

I sold a boiler and new thermostat to an engineer and he used to time the heating and off cycles. He was retired. He made me replace the thermostat with a t87 because he said it affected the heating cycles.
Ray

You got to love engineers! I would have set the heat anticipator to the longest setting, then the next year set it to the shortest setting. Tell him he was crazy if he called to complain. Then the next year set it to the longest setting again. Just to piss him off. In the 4th year I would tell him what I did... LOL

Yo got to love engineers!

ChrisJ

EdTheHeaterMan said:

I have two stories. I used to have a customer that referred to his heating system as the Honeywell Heating System even though he had a Weil McLain boiler. I sold a boiler and new thermostat to an engineer and he used to time the heating and off cycles. He was retired. He made me replace the thermostat with a t87 because he said it affected the heating cycles. Ray

You got to love engineers! I would have set the heat anticipator to the longest setting, then the next year set it to the shortest setting. Tell him he was crazy if he called to complain. Then the next year set it to the longest setting again. Just to piss him off. In the 4th year I would tell him what I did... LOL Yo got to love engineers!

Does that include the engineer (s) that created the T87?

mattmia2

I'd be interested to see its cousins. Is there one with an adjustable deadband? Is there one with offset? Is there one with high and low limits? Were some of these things accessories? What about line voltage? There certainly are mercury switches that can do it. My house had one that was 2 stage but if i recall it was a little weird. It controlled an old gravity furnace that was installed new with a blower and had a second gas valve sort of kludge in to it to make it 2 stage. It was the style of gas valve that you could take apart by loosening a big nut.

Jamie Hall

So far as I know the straight T87 does not have an adjustable dead band -- that is set by the weight of the mercury being in one end of the tube or the other, affecting the spring. What it does have is the anticipator, which works to heat the bimetal spring and flip the switch over faster or slower.

There were at least two flavours of T87 -- one a "normal" range -- say 55 or s0 (I'd have to look) to about 80, and one low range, 35 to 75. The effective stops were simply how far you could turn the assembly!

Line voltage would take a different mercury switch -- like the one in a mercury vapourstat. The switch in the T87 is very small, and it wouldn't reliably switch line voltage.

retiredguy

This should probably be written under the question "you want to hear a good one" by EdTheHeaterMan, but here goes. When I got out of Tech school in 1968 and started with a now closed HVAC company, the head service tech said that I had to learn how to install a T87F Honeywell thermostat on a white plaster wall with dirty fingers and not put any mark on that wall. He had a vertical test board that he made up with a piece of drywall he could replace as necessary. He handed me a new T87F and sub base an was told to install it on his test board but first I had to first wipe carbon black (soot) on my finger tips. he said that I had to be able to mount the T87 and leave no marks on the wall

DanHolohan

@retiredguy, that was one smart tech. I imagine you passed the test.

GGross

@retiredguy

I hope when you pulled a pair of gloves out of your pocket you were offered a raise on the spot

Labenaqui

..... and the T86's that preceded it. Digging through our 1960's NEFI School Manuals, the T87A's are there, and pages appropriately smudged. They correctly called us "Soot Chasers" back then with good reason!
Don't remember ever changing one, but upgrading White-Rodgers, Penn Controls and others.
The first thing we checked with a new customer was the thermostat anticipating heater setting.
I was working for Honeywell (Computer Operations) when they went Mercury-crazy and stuck Honeywell with a boodle of them.
I miss the adjustable anticipater when tuning a steam system. These digital plastic T-stats with a fixed Dip switch setting just don't make the grade.

ChrisJ

Labenaqui said:

..... and the T86's that preceded it. Digging through our 1960's NEFI School Manuals, the T87A's are there, and pages appropriately smudged. They correctly called us "Soot Chasers" back then with good reason! Don't remember ever changing one, but upgrading White-Rodgers, Penn Controls and others. The first thing we checked with a new customer was the thermostat anticipating heater setting. I was working for Honeywell (Computer Operations) when they went Mercury-crazy and stuck Honeywell with a boodle of them. I miss the adjustable anticipater when tuning a steam system. These digital plastic T-stats with a fixed Dip switch setting just don't make the grade.

The issue I had with the anticipator is it's a fixed setting.  I played around with it quite a bit and could get it to work amazing..... Until conditions changed.

Unfortunately any system with a lot of mass like a steam system will only work right on similar days to when you set the anticipator.  On colder days it'll overshoot more and more the colder it gets.  And it'll undershoot on warmer days.

The digital thermostats from Honeywell adjust their anticipation, at least the best they can with what they have.  The CPH adjustment is just to get it in the neighborhood and is basically a sensitivity adjustment, not a hard rule by any means.

They would do better if they took outdoor temp into consideration rather than just guessing by how much the system under or overshoots.

Regardless, the fixed anticipator (adjustable but not in real time) was better than nothing, but isn't as good as more modern stuff.  

Jamie Hall

The merits -- or otherwise -- of the anticipator have always been debatable. And it depends a LOT on the skill of the tradesman setting it, which is a real disadvantage, I acknowledge that. That level of skill is really hard to come by these days. Plug and play is the word.

ChrisJ

Jamie Hall said:

The merits -- or otherwise -- of the anticipator have always been debatable. And it depends a LOT on the skill of the tradesman setting it, which is a real disadvantage, I acknowledge that. That level of skill is really hard to come by these days. Plug and play is the word.

No matter how much skill there is it's a fixed setting that doesn't adapt to conditions and conditions change constantly.

mattmia2

In theory it is supposed to be set to the current of the control it is operating, right?

ChrisJ

mattmia2 said:

In theory it is supposed to be set to the current of the control it is operating, right?

That's the rules they came out with but it depends on the system.

All it is is a heating element that warms the bimetal spring a little to shut the system off early.  It works very well under stable conditions.

The adjustment changes how much it heats it and since it uses the current from the appliance that's there that comes in.

The standard setting for steam is 1.2 which is memory serves is technically (off).