Taco PC700-2 boiler reset
#1
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Taco PC700-2 boiler reset
I have a taco pc700-2 plugged into a taco SR 504 EXP running my hot water boiler,with BB hot water heat.Not sure if it is working right or not.My settings are---Boiler start-70---outdoor 70--boiler design 180 (have boiler set for max 185 before shut off,have PEX in whole system) ---outdoor design 5----boiler min 145----diff Ad ----wwsd off.I don't understand that if the pc700-2 panel says boiler target is 145 why does the boiler go off at 172 on the panel.This was when the outside temp was 34.Other times out side temp was 50 and boiler target was 145 and it went off at 172. Maybe I do not understand what boiler target means.
#2
Your settings all appear correct.
(except for possibly the outdoor design temp. I believe NYC is 10°... but this should not cause what you are seeing)
Do you have the switch in the 504 on RESET?
Do you have an indirect water heater on the system?
How long has the 700 been connected and operating? They need a little time to 'learn'. The AUTO DIFF in particular... perhaps the control is still 'adjusting' the diff? To learn if this is the cause, you could set the DIFF to manual, and use say 20° for a while and observe.
Remember that every time you make changes to the setting, the control needs to 're-learn' the building and boiler.
Does the boiler temperature gauge agree with the reading on the 700 display?
(except for possibly the outdoor design temp. I believe NYC is 10°... but this should not cause what you are seeing)
Do you have the switch in the 504 on RESET?
Do you have an indirect water heater on the system?
How long has the 700 been connected and operating? They need a little time to 'learn'. The AUTO DIFF in particular... perhaps the control is still 'adjusting' the diff? To learn if this is the cause, you could set the DIFF to manual, and use say 20° for a while and observe.
Remember that every time you make changes to the setting, the control needs to 're-learn' the building and boiler.
Does the boiler temperature gauge agree with the reading on the 700 display?
#3
Auto differential (Ad) may have something to do with it. The boiler will shut off when it is (differential/2) ABOVE the target temp.
Granted that would be a 54 degree diff, but it may contribute to what you're seeing.
172 is the temp when the boiler actually stops firing?
Granted that would be a 54 degree diff, but it may contribute to what you're seeing.
172 is the temp when the boiler actually stops firing?
#4
172 is the temp when the boiler actually stops firing?
Bill, if you are reading this temperature some time AFTER the pump has shut down, it could be due to something called 'heat soak'.
You did say:
boiler target was 145 and it went off at 172
Boiler water temperature can INCREASE significantly AFTER the circulator shuts off, because the heat that is trapped in the cast iron transfers to the boiler water.