We have an in-floor hot water radiant heating system installed, under hardwood flooring. Heating source is both a water-water geo heat pump (primary - Carrier 50YER060) and propane boiler (secondary - triangle tube prestige solo 175), which are both connected to a hydronic storage tank (HTP SSU 80) that then feeds the various radiant loops. Tstat sensors are wall mounted in the various zones.
As currently wired, the Ranco tstat that controls target temp of the hydronic storage tank is “slaved” to the various radiant zone tstats, such that there has to be an active call for heat from one of the zones in order for the Ranco to receive power.
I have set the Ranco target at 92* - was told by my local tech that a water-water geo pump will struggle to get much above that, given that max temp is ~110-120*, less losses in the transmission from heat pump to hydronic tank.
However as the weather is warming up (New England) I’m noting that this can result in the Ranco being dark for a good part of the day, such that when the ambient temp cools down in the evening and the radiant zone tstats start calling for heat, the hydronic tank temp will be below its target temp by as much as 10*.
Is this the most efficient/cost effective way to run this sort of system? Or would it be better to have the hydronic storage tank set at a constant target temp (no power interrupts to the Ranco tstat) to avoid larger cyclical/startup demands during the colder part of the day?
Thanks in advance
As currently wired, the Ranco tstat that controls target temp of the hydronic storage tank is “slaved” to the various radiant zone tstats, such that there has to be an active call for heat from one of the zones in order for the Ranco to receive power.
I have set the Ranco target at 92* - was told by my local tech that a water-water geo pump will struggle to get much above that, given that max temp is ~110-120*, less losses in the transmission from heat pump to hydronic tank.
However as the weather is warming up (New England) I’m noting that this can result in the Ranco being dark for a good part of the day, such that when the ambient temp cools down in the evening and the radiant zone tstats start calling for heat, the hydronic tank temp will be below its target temp by as much as 10*.
Is this the most efficient/cost effective way to run this sort of system? Or would it be better to have the hydronic storage tank set at a constant target temp (no power interrupts to the Ranco tstat) to avoid larger cyclical/startup demands during the colder part of the day?
Thanks in advance
source https://hvac-talk.com/vbb/threads/2227412-On-demand-vs-constant-thermostat-control-of-hydronic-tank-for-floor-radiant-heat?goto=newpost
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