I'm helping someone puzzle out a system-
Radiant hydronic in-floor, gas boiler, circulator pump located near the
loop, not at the boiler:
- room thermostat is paralleled with a thermostat in the mixing valve
- room thermostat 'sends' a call for heat to the boiler
- circulator pump is controlled by a goldline SP32D, set to turn on
the circulator when the sensor (don't know for sure where it is) is
below 60 deg. F.
Does this sound like I've puzzled it out somewhat correctly?
Is it normal to leave the circulator pump on below some sensed
temperature (sensed in the slab? outdoors?), and just use the call for
heat to modulate the water temperature?
More precisely, it's normal for the circulator to run when there is a call for
heat. If the water is hot enough already to satisfy the demand, there is no
need to light up the boiler. If the water is not hot enough, there is. Some
controllers are sophisticated enough to "know" when they need to light up the
boiler and when they don't, and some are not. I don't know which category your
SP32D falls into.
Doug Miller (alphageek at milmac dot com)
On Jan 23, 8:21 pm, email@example.com (Doug Miller) wrote:
The SP32D just looks at its setpoint (60), compares it to the remote
thermistor, and activates the relay when the thermistor is below the
It doesn't seem quite right to me, either, I've dealt with oil forced
air, gas forced air, oil-boiler hot-water baseboard, and figured this
would be the same.
Well, I haven't exhaustively traced the leads off the relay, so since
the way it seems to be hooked up doesn't seem likely, I'll dig into it
On Jan 23, 4:47 pm, firstname.lastname@example.org wrote:
I have confirmed that the thermostat (paralleled air thermostat and
water loop temp thermostat only does the call-for-heat to the boiler,
and that the circ. pump runs whenever the outside temp. is below the
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