No zone valves on my system

[bentz69]

I have oil heat with 3 zones/3 thermostats (basement, 1st/2nd floor) using baseboards. The 3 thermostats are 110v line voltage units that operate the 3 circulator pumps. There are no zone valves on this system. I would like to install 3 Nest thermostats to replace these old line voltage units.

My plan is to install three 3 zone valves. I will re-use the current wiring (no plans on running new wires through the walls) to give the Nest's the 24v it needs by having the power supplied by a transformer. The Nest's will operate the zone valves and I will wire the micro switches in the zone valve to the circulator pumps to supply the pumps 110v to operate. Ive seen several systems that use the Nest which don't have a dedicated C wire and they work fine with no power lose over long term periods of non-usage.

Looking for input. Thanks

 

[shaun1]

The nest heat link can switch upto 3A so could be used to switch the pump (assuming it draws less than this). So you may not need to add a zone valve if it isnt otherwise required. Are the pumps 12V as well? You should still be able to switch these through the nest as the switching contacts are independant of the power supply.

You can also power the thermostat from the heatlink down the existing cable if you have at least 2 cores between the heatlink and thermostat.

 

[bentz69]

I was adding zone valves because of the constant thermosiphon effect throughout the winter. I will get tremendous amounts of heat specifically on the 2nd floor when the thermostats are off

Pumps are astro armstrong at 115v

 

[bentz69]

The nest heat link can switch upto 3A so could be used to switch the pump (assuming it draws less than this). So you may not need to add a zone valve if it isnt otherwise required. Are the pumps 12V as well? You should still be able to switch these through the nest as the switching contacts are independant of the power supply.

You can also power the thermostat from the heatlink down the existing cable if you have at least 2 cores between the heatlink and thermostat.

I see the heat link is only available when you purchase a nest thermostat in Europe. I already have my 3rd gen thermostats and cant even find used heat links for sale.