Do You Go By the Temp. Gauge or Aquasat Setting (oil boiler)?

[velvetfoot]

I'm trying to make sure my Argo outdoor reset (DPM-2) is working right.
It's max temp is supposed to be set less than the boiler temperature setting.
I'm finding that the temp. gauge is less than the aquastat (Honeywell) setting.
Should I go by the temp. gauge?
Would a boiler setting of "180F" mean the burner goes off at 175F and then the boiler runs up to 180F or would it mean that the burner shuts off at 180F?

There's not too much documentation on the operation of the reset unit, and it doesn't have any jazzy displays or anything

brochure: (broken link removed to http://www.ecrinternational.com/secure/upload/document/513.pdf)

 

[Nofossil]

Sounds like you might have to experiment. Keep a notebook with settings and observations.

Most heating systems use the setpoint as a maximum and turn off heat when the setpoint is reached. The heat will come on again when the temp has dropped some amount below the setpoint. That amount is sometimes called 'deadband', and sometimes it's adjustable.

Aquastat dials are usually not calibrated in any meaningful way, so I'd use the temp gauge.

 

[Chris S]

I'll add that it is not uncommon for a boiler to overshoot the aquastat setting by a few degrees. On the design day with a heavy load on the boiler- not as much, but with a light load ( zones not all running) this can happen. Some boiler manuals even refer to it.

 

[velvetfoot]

Hey thanks. I'll trust the temp gauge.
Hopefully I have a 'warmer' feeling about the outdoor reset module's operation.