round white honeywell thermostat

oilman wrote:Stay away from any "power stealing " thermostat- this would be a digital style that does not have 2 to 4 aaa or aa batteries. They don't work right and they can also damage oil and gas controls on conventional heating units.

I am of just the opposite opinion. I would never have a thermostat that forced me to spend $4 every year or so. I purposely look for thermostats that do not need batteries replaced and that are powered by the same 24 volts AC that powers the boiler controls. I have never known one to damage controls, nor do I understand how one could, nor how you would know or prove that a thermostat caused damage to controls.

A thermostat should last about forever, but, for sure, this transition to non mercury thermostats has not been good. There's a bunch of junk out there and most manufacturers have had growing pains and a learning curve that is taking them off the road. Basically, stick with a name brand and try to pay more than $10 for a one.

I bought one of those new thermostats that were programmable for 7 days for my oil furnace the year before I bought a coal stove. The furnace only ran in the morning and the evening. It was programmed to run every 45 minutes. It was lucky it ran every two hours. I'd come home from work and it'd be cold. I took the new one off the wall and put the original rectangular one in that has a mercury switch. It's pretty sad that the one from 30 years ago works better than the new one.

But now, I don't even use it. It's just a decoration on the wall.

Pretty hard to beat a mercury switch for reliability.

Hmm, maybe I will just stick with the stock manual thermostat. I looked on ebay for vintage heating thermostats and actually found an old round honeywell with mercury.. maybe i'll bid lol. Would that work with the Keystoker 90?

Freddy wrote:

oilman wrote:Stay away from any "power stealing " thermostat- this would be a digital style that does not have 2 to 4 aaa or aa batteries. They don't work right and they can also damage oil and gas controls on conventional heating units.

I am of just the opposite opinion. I would never have a thermostat that forced me to spend $4 every year or so. I purposely look for thermostats that do not need batteries replaced and that are powered by the same 24 volts AC that powers the boiler controls. I have never known one to damage controls, nor do I understand how one could, nor how you would know or prove that a thermostat caused damage to controls.

A thermostat should last about forever, but, for sure, this transition to non mercury thermostats has not been good. There's a bunch of junk out there and most manufacturers have had growing pains and a learning curve that is taking them off the road. Basically, stick with a name brand and try to pay more than $10 for a one.

I'm referring to digital set-back thermostats. Cheap ones. I am not referring to snap action or mercury.
I know that they damaged certain 7184 series primary relays.
I didn't realize you were a heating contractor . You must be to be so sure of things.
I have been working on heating equipment since 1980 and dealing with homeowner installed Big Box thermostat problems for about 20 years now. You?

Mercury thermostats were the standard for years there simple and very reliable. However they have become obsolete mainly because they have mercury in them and its probably cheaper to make a circuit board.

Ps. My dad turned the mercury thermostat on for his propain boiler so he could lower its lowest temp to 40F (house I'd heated by a corn stove) you can't do that with a digital

oilman wrote:I have been working on heating equipment since 1980 and dealing with homeowner installed Big Box thermostat problems for about 20 years now. You?

I'm a licensed plumber & have messed with heating systems since 1973. In Maine a plumber can do everything a burner man can do except place a boiler in it's final spot and light a burner for the first time. I did hundreds of heat system installs and "no heat" calls through the 90's but not so much now. Now I don't even practice plumbing other than my own stuff and to help friends & neighbors.

You mentioned it was the cheap thermostats that gave grief. I agreed with that buy suggesting to buy a brand name and not buy cheap ones.

Freddy wrote:

oilman wrote:I have been working on heating equipment since 1980 and dealing with homeowner installed Big Box thermostat problems for about 20 years now. You?

I'm a licensed plumber & have messed with heating systems since 1973. In Maine a plumber can do everything a burner man can do except place a boiler in it's final spot and light a burner for the first time. I did hundreds of heat system installs and "no heat" calls through the 90's but not so much now. Now I don't even practice plumbing other than my own stuff and to help friends & neighbors.

You mentioned it was the cheap thermostats that gave grief. I agreed with that buy suggesting to buy a brand name and not buy cheap ones.

I seem to have the best luck with White Rogers. However, the 5000/6000 series Honeywells are pretty good. I also like the Luxpro PSD010.
Those thermostats sold in retail are not the same as the others. I guess they are cheaper made or something. Just like the Moen or American STD. et.al. fixtures are
specially made for HD and Lowes. Not like Pro models.

I found a new old stock Honeywell T87 mercury therm on eBay and won it. Should get here tomorrow, I'll hook it up and post how it works out.

Ok, the old vintage T87 is hooked up. It works but it looks like I have to play around with the heat anticipator, any tips on setting this?
The therm is located upstairs, the stove is downstairs if that matters.

Here ya go:

adjust-honeywell-thermostat-heat-anticipator

McGiever wrote:Here ya go:

adjust-honeywell-thermostat-heat-anticipator

Thanks for the link! Looks like I need to buy an ammeter.

I checked the amps with a meter (digital multimeter set to AC and 0-10 amp lead connection, not milli-amp) I get 0.0065 so I assume this means I should set the anticipator to the .6 setting? Keystoker told me to set it at 9.... which isn't listed on the scale, unless between .10 and .12 but that is nearly at the longest burn time of the scale. This is my first time using a meter, so not familiar with the settings but after reading the instructions it seemed that I have it set up right to take the reading.

Where you have it set is just a starting point. What you want is to avoid too short running times which are inefficient yet if too long the room temperature will not hold closely. So you will have to experiment to find the ideal spot. It should hold within 2 degrees.

franco b wrote:Where you have it set is just a starting point. What you want is to avoid too short running times which are inefficient yet if too long the room temperature will not hold closely. So you will have to experiment to find the ideal spot. It should hold within 2 degrees.

Ahh, ok I see. Well, I will have to tweek it in the fall I guess. Looks like I'll be finally shutting her down for the summer very soon. At least I have the therm in the ballpark ready to go for the next heating season. Now it's time to save up for coal....

Thanks everyone for the help so far!