New T87

Epeter

I replaced my old mercury T87 and am using the recommended micro switch settings for steam. Is this the best option? And is this the best 'stat for the old one pipe system?

jpf321

with what did you replace it?

what did you replace it with? likely ... if it has a steam setting, and you have set it for steam, you are in good shape. 

nicholas bonham-carter

new thermostat

many people here like the honeywell visionpro, because it can have a remote sensor. many thermostats were not always located in the optimum location for sensing temperature, and the remote provides this alternative location. especially for apartment houses, the control panel can be in a lockable area. while the sensor is in a cooler area of the building.

honeywell also have the prestige, which is wireless, and internet accessible.--nbc

Epeter

New T87

Replaced with new T87N the old one was set at 1.2 (max).

Is this stat a good (enough) choice?

Much thanks and Merry Christmas.

Epeter

New T87

Replaced with new T87N the old one was set at 1.2 (max).

Is this stat a good (enough) choice?

Much thanks and Merry Christmas.

crash2009

T87 Old Style

I am using the old syle T87.  I have tested the 1.2 setting before.  Save lots of fuel with 1.2.  Runs long and hard, shuts off for a long time.  1.2 was a little uncomfortable for us though.  For this building we got a 4 point spread. The building was up and down like a yo-yo.  68-72 F when we were set to 70F.  For this place 1.0 seems to work well.

How do you like the new style so far?

crash2009

Manual

I was just looking at the manual for your new one.  If you have a steam boiler set your CPH to 1.  See page 4  http://customer.honeywell.com/techlit/pdf/PackedLit/69-1840EFS.pdf

ChrisJ

crash

You mentioned 1.2 on your older Honeywell saved fuel. Are you sure about this?



Reason I ask is I have been unsuccessful at getting my t87f to work right with any setting other than 1.2. I always get it shutting down just before 2nd floor rads get steam.



1,2 gives me the same results you saw, shuts off for a long time and runs a long time when its on. Wide temperature swings THOUGH we can tolerate them if it is indeed saving us fuel. I think even at 17F out it only ran every 2 hours or so if that.



I've seen people mention this may be wasting fuel, it its saving fuel I'll just leave everything alone.

Jamie Hall

IMHO...

the old mercury T87 thermostat, properly set up (that is, with the anticipator really adjusted to the system) was about as good as it gets for steam -- provided you don't need a programmable setback.  Which, of course, it doesn't do.  They were fiddly to set up properly.



They were absolutely dead reliable.

Mike Kusiak_2

T87 anticipator setting

I agree with Jamie that the mercury T87 is a very good choice for a steam system if you don't need programmability. Hard to beat the reliability of a simple bimetallic spring and mercury switch.



Have you tried an anticipator setting just slightly below 1.2?  At that end of the scale, the graduations are very compressed and a slight movement can make a big difference. At 1.2 the anticipator heating resistance is effectively shorted out, so there is no anticipation and you are working off the inherent 2 degree thermostat differential.  The thermal characteristics of the system and building can widen the effective differential to 4 or more degrees without anticipation.



I would suggest trying setting the anticipator to just a hair below 1.2 and see how the system cycles. Am also curious about the cycle times with the digital T87 when set to 1 CPH and how they compare.

ChrisJ

anticipator

I tried having the anticipator on just about as high as I could without turning it off and still noticed a problem, at least on mild days.



After the last time I just gave up and set it on 1.2 (off) and pretty much decided thats just how its going to be at least for now.



Maybe if I tweak my balancing more, put faster vents on the 2nd floor i'll be able to get the anticipator to work right. I assumed Hoffman 1As wide open would be enough. When I get home this week I'll have a closer look at the way its made.

crash2009

Nah,

 not sure if you save anything.  Especially when you factor in wear and tear on the sweater. 

Long Beach Ed

Chinese Junk

We've replaced countless Honeywell electronic thermostats that failed either at zero degrees or 99 degrees.  They've frozen pipes in buildings causing thousands in losses or ran boilers for weeks causing huge fuel costs when they failed. 



Incredibly undependable, inaccurate and unable to set reliability.



Don't waste your time with Chinese electronics.  Stick with the mercury stats if you have a choice.  They will never hurt you. 

Epeter

New T87

I am going back to the old T87. After replacing the near boiler piping with a high riser and drop header (thanks to Rods excellent drawings) and finally getting the system clean (ish).

http://www.heatinghelp.com/forum-thread/138143/Thanks-Rod-Near-boiler-piping



I am not getting enough cycle time in the so far mild NY weather.

In the past I had the anticipator set to 1.2 (just because).



1926 Long Island Dutch Colonial

Self renovated back in 1987 and self maintained (weekly).



Any idea where to find the instructions for the anticipator settings.

Mark N

Anticipator Setting

Chris



I think you have a Weil-McLain EG boiler from previous posts. IF I were you I would refer to the EG Controls Supplement. On pg 21 you will find the info or properly setting up the anticipator on your tstat. The supplement is available on the web site.

Jamie Hall

Which is why...

I have two backup mercury T87s (one a special low temperature model) in the colder corners of the buildings...

haaljo

one mercury and one visionpro in house.

One less control to be single point of failure. Have a firstalert autostat adapter for the chrontherm merc. The chonotherm has night setback with a windup eggtimer. The firstalert accesory provides night setback "automatic" by mechanical manipulation of the stat temp levers. Had one for a T87 years ago.

Fun to watch the gizmos change temp.

Bought on ebay. Made in 1984; "Assembled in Hong Kong." That boat started to sail away 30 years ago.

icesailor

Old T87's

Are the old T 87's even available anymore? Every time I need a new T 87, I'm a quandary about what to do with the old one and the mercury inside.

I agree with setting the anticipator to 1.2 amps. But, do any of you all ever put an "Amp-Mate" meter to see what the control amperage is running through the thermostat? I found that with Taco 571 zone valves that draw .09 amps, if an old style mercury T 87 thermostat is used, they come set at .04 amps and if the power was sent to the T 87, the heat anticipator rheostat would almost instantly burn out. Only to short cycle forever, no matter what you set it at later.

Just curious.

haaljo

Can't even find them 2nd hand on ebay.

The mercury is recyclable. My town tranfer station excepts them (near Boston). They have an exchange program with a "digital stat." Think it's funded by utility.

Interesting comment on burning out the anticipator.

crash2009

Ice

I remember you explaining how to test for amps in a previous thread.  It had something to do with 10 loops and a ampmeter.  I didn't understand how to set that up.  Could you explain that for us?

ChrisJ

mark N

Mark,

You are correct, I have an EG series with EI and a damper. It recommends 0.7A for my configuration and this actually made the boiler shut off before my 1st floor rads got any steam. 0.9A was still too much compensation.



This is why i decided just to go with 1.2A. My main concern is fuel consumption more than comfort.

Mark N

How Long?

Chris



How long did the boiler run when the anticipator was set at 0.7a? How long does it run set at 1.2a? There is the possibility that the tstat is no good.

ChrisJ

run time

Mark,



I'll start timing it this week and get some real numbers for you. If it helps when I bought the house there was a Beckett AFG connected to the T87F and the anticipator was set on its default setting, .6 or .4A whichever it is. Not sure if this would help predict if any damage was done?



The boiler takes around 15 minutes to start producing steam from an ice cold start. I can assume with the anticipator set to 0.9 it was shutting off after 17-18 minutes because I just start getting steam to the radiators and it shuts off. With it set to 1.2A I get a good 25-30 minutes out of it.



Perhaps I'm making a mistake in only letting it run one cycle with the new anticipator setting and then I immediately reset it back to 1.2A rather than let it run a few times??

Mike Kusiak_2

Settings

If the thermostat is behaving as you describe, I doubt there is anything wrong with it. The anticipator is just a resistive heating element. The fact that it varies the cycle time when you change the setting shows it is working properly.



The manufacturers recommended settings are just to get you into the ball[park. They have no way of knowing the specifics of your system. Depending on type of radiation, location of thermostat and level of insulation of the building, the proper anticipator settoing can vary widely for a given cycle rate. Only by calibrating by trial and error can you achieve the proper adjustment for your system and preferences.

ChrisJ

patience

Is it a mistake to try one setting and then immediately give up on it after only a single cycle? I'm wondering if its my own fault for not allowing the system so stabilize, though I have to assume on mild days its going to have the same effect no matter what. Running for 17-18 minutes and shutting off without delivering any heat only to fire right back up 10 minutes later.

Mark N

Temp Setting

Chris



Do you leave the tstat at a constant temp or do you set it back at night or when your at work? The colder it gets the better steam systems run. The boiler stays off less in between cycles so the water is hotter the pipes are hotter and the steam get to the rads quicker. I went to a Honeywell FocusPro last year. The cph is set to 1. This tstat maintains a very uniform temp. I keep the house at 70 and we are comfortable and the heating bills are very reasonable.

ChrisJ

temp

I maintain a constant temp around 69F.



You mention a FocusPro, which model did you go with? I was considering going with an 8000 series visionpro only because many people recommend them.



If a focuspro would give me the same results I'd rather go that route for obvious reasons.

Mike Kusiak_2

Adjustments

I would not try to adjust the anticipator in mild weather as it would not  representative of operation under typical winter conditions. Probably the best would be at 20 to 30F outdoors.



The system has to stabilize for a few cycles so I wouldn't make any judgements until you gave it some time.  You probably want a setting just a hair under 1.2 to get a long enough cycle to distribute steam properly, yet not result in overshoot and wide temp variations. A 20 to 25 minute firing time sounds about optimum.

Mark N

FocusPro 5000

Chris



I have the FocusPro 5000. I didn't need a programmable tstat. Mine is set up for heating only. I ordered mine through pexsupply.com.

BobC

setting up for low currents

The way a clampon amp meter (amprobe) works is to "read" the current going through it's clamp. Most of these meters have a 15 amp scale as the lowest range, If you loop 10 turns instead of 1 turn that effectively becomes a 1.5 amp scale. It's a lot easier to read low currents this way. Some types have a 6a scale but they all have a 15a scale available.



Just open up the jaws and wrap the turns around one side of the jaw and hook it up across the thermostat terminals on the boiler and you will be able to measure the current that boiler needs to run and can set your anticipator accordingly.



The enclosed picture shows my Sperry amp probe with wire looped around the jaw.



Bob

crash2009

Oh

 that's what Ice was talking about.  Thanks Bob.  So the two ends of the green wire go to the thermostat connections on the boiler.  I had visions of connecting this to the thermostat, upstairs, to see what I have just adjusted the anticipator to.  I thought it could be used for a numerical confirmation of what the anticipator was set to. 

ChrisJ

patience

Apparently I'm just a dope.



I tweaked some vents today and set the anticipator to 0.9 for right now. The first time she fired up cold it did the usual and shut off just before any radiators got hot. I waited and it fired up again and I started to get heat.



I've had it there for a while and my temperature has remained very stable with the boiler only heating the first few sections of the radiators for the past few hours. See, this is how I get my self into trouble by over analyzing things.



I'm going to spend the rest of my day tweaking and fine tuning more.

BobC

either way

You could hook it up to the wires on the thermostat or the other end of the thermostat wire on the boiler, it would read the same either way.



Also my picture shows 5 turns of wire because the clip lead I had handy was not long enough for 10 turns. If you did use 5 turns on the 15a scale you would effectively turn the scale into 3 amps (15a/5turns=3). It's easier to use the 10m turns so you just divide the meters scale by 10.



Bob

ChrisJ

current

Ok,



I removed my T87F and fired the boiler up using my Fluke 279 as an ammeter across the connections for the t-stat.  I measured 0.5A once the system was running.  This is quite a bit lower than the recommended setting of 0.7A for this configuration. 



Does this mean I should use 0.5A as my anticipator setting?

haaljo

Nice. Wonder why the boiler shut off on first firing?

If the stat wasn't satisfied shouldn't it have kept on running?

Mike Kusiak_2

Your'e overanalyzing again!

The absolute value of the circuit current is not what's important. Rather its the heating effect of the current in relation to the complete system parameters that determines the cycling rate. The 0.5 amp setting may be correct if you want to run 5 cycles per hour, but it certainly would not be suitable for a steam system.



You know now that a 0.9 setting is giving you even temperatures and about 2 cycles per hour. Use that as a starting point and fine tune from there. If you are shooting for about 1 cycle per hour which would be better for efficiency, the you will have to set even closer to 1.2.



Don't get caught up in trying to set to the actual circuit current because that's not going to get you the right result,  particularly for a steam system.

Mike Kusiak_2

Anticipator heating

That's the whole purpose of the anticipator. The thermostat circuit current heats the internal anticpator resistance to fool the thermostat's temperature sensor into shutting down early. That way, the residual heat of the cast iron radiators doesn't overheat the room. The thermostat shuts down early and the system "coasts" up to the thermostat setpoint temperature without overshooting it.



Chris's thermostat shut down not because he reached the room temperature setpoint but because the internal anticipator heater fooled it into thinking it did.

ChrisJ

ok

I understand.



What is a bit confusing is why did Honeywell recommend 1.2 for steam? Was it simply because most people would not know what to do and it would result in endless support calls?