setting anticipator on t87

Bob W._3

My experience is that there is a certain amount of imprecision involved with the T87 anticipator settings. Mine amps out at .3, which is too low a setting. My boiler manual says to set it at .8, which gives too long a burn and too long a down time. I have it at .55 which is giving me about 2 cycles per hour. BTW, I always shut off the power before adjusting the anticipator, per the recommendations given on this Board. Good luck

Joe_39

can someone clarify

the proper way to set the anticipator on a honeywell t87?

The manual I believe said to hook up a multi meter and use those readings.. I have a multimeter what setting should I put it on?? THis is for 1 pipe steam, I use 2 wires on the stat..

Also if you increase the setting does that mean it runs longer??

Jack P.

Ah, the old standby Honeywell T87. Must be 10 trillion of those out there. Take off the cover (beige ring just outside the dial) it just pulls off. In the lower right had side is little lever with a point on the end. Behind the lever is metal plate with lines and numbers stamped on it. The numbers are .3 -.4 -.5 etc. and are tenth of volt markings. Note what number the pointing lever is set. With a pen or pencil point move the lever to one setting higher or lower. Higher number is longer cycle, lower is shorter cycle. Adjust only number at time and let the boiler run a cycle or two. If you want the cycle longer or shorter, whichever the case move one more number in the desired direction until the cycle length is reached. If this is a new stat start at .4 and set up or down from there.

Empire_2

Amp probe

To check the anticipation you will need to remove the entire stat to expose the subbase. With t-stat wire, wrap it 10 times around the jaws of your clamp on amp probe. jumper the two wire for the heat circuit and cycle for about a minute or so. Note the reading. this is your anticipation setting. In addition and in my opinion boilers have no anticipation (they are either on or off) so I set my stats at about 1.0 or so. With multi meter,...choose your anp setting on its lowest scale 1 to 6 or 10 I believe depending on your meter. Again jump out your heating circuit with the meter in series with the circuit.

Dick Charland

Correct and incorrect

Mike, you are correct boilers in and of themselves do not have anticipators, but the controls that operate them do. The best way to check is taking an amp reading as described or with a meter that will read the lower amperage. On oil, cad cell controls are typically rated at .2 amps, stack relays were rated at .4, circulator relays were also in the same range. Taco power heads should be set at 1.2 amps because of their high amp draw. On the gas side, gas valves I'm told may run at .6 amps and I've seen boilers with two gas valves go higher. The end result is there is no universal setting and the system will operate well as long as the thermostat anticipator is set correctly.

Joe_39

Ok I got you about the cycles, but will this help

with boiler going off on pressure?? I do get heat coming from the rads before it builds pressure and shuts down..

I am thinking the cycle time is too long and she is running too long and not giving the tstat the chance to react??

S Ebels

How I do it

Remove the T-stat from the base, connect leads of your meter to the R-W terminals with meter on Milliamp scale. The reading you get should be the load of the gas train. Note, if the appliance has a prepurge or anythign like that, wait until the main valve opens in order to get the correct reading. This will give you a basic starting point for your anticipator. Probably 80% of the time I have found this setting to be close and it will work fine. Other times, and this depends on the warmup time of your system, you may find a higher or lower setting delivers what you are after. The higher the Ant. setting the longer the run time.

curiousity kills

buy a digital tsat

Joe_39

what will that accomplish?

will smith_4

Digital stats-

Don't have adjustable heat anticipators.

curiousity kills

they are easier to read temp you do not have to set the anticipter and it tells time

Nick W

He's right and wrong, digital stats don't have heat anticipators, but they do have cycle timers. For instance on a Honeywell digital stat, there are screws or dip switches you may need to set. On white-rogers, you have to enter the configuration mode. In any event when doing so, read the entire instructions.