Honeywell TH2110DH1002 wired in parallel

hotsauce

Can the Honeywell TH2110DH1002 thermostat be wired in parallel? I have 3 rooms on the north side of an older house that were once heated with radiant ceiling. I am replacing that style of heating with Pensotti Double Panel radiators. My only goal is switching the circulator on and off according to heat demand by any one of the three rooms. TIA!

Jamie Hall

Wired in parallel... with what?

Ironman

I think you’re missing the fact that if any one of them were on they’d all be on. So, what would be the purpose?

hotsauce

Ironman said:

I think you’re missing the fact that if any one of them were on they’d all be on. So, what would be the purpose?

Not missing that at all. The TRV's will see to it the water only goes where it is wanted! But if there is a better way to do this I am all eyes and ears

hotsauce

Jamie Hall said:

Wired in parallel... with what?

Each other so that if any room calls for heat the circulator turns on. No rooms calling for heat = circulator off. My big concern is where one of the thermostats is calling for heat but all TRV's are off? The circulator is going to be a variable speed delta P or T.

Jamie Hall

If you are using TRVs, then you only need one thermostat in the coldest room. You might need a delta P pump or some sort of bypass so the boiler maintains circulation in the odd circumstance that the thermostat is arguing with the TRV in that room and calls for heat with all the TRVs closed.

Or you could wire three thermostats in parallel to run the circulator and the boiler -- but you still will need either the delta P pump or a bypass to protect the boiler if all the TRVs are closed but a thermostat is calling. Which, by the way, WILL happen sooner or later.

EdTheHeaterMan

I think I understand what you want to accomplish, but it won't work. You want to stop the circulator from deadheading when all three TRVs are closed. You want the thermostats to do that. But you want the TRVs to keep the "Other Rooms" whichever ones they may be, to keep the room from overheating.

Sounds like a good theory, however a room thermostat can be set to 80° by someone who does not understand the concept (I know ... that will never happen... until it does and you destroy a circulator pump 5 or 10 years from now). If any thermostat calls for heat and all the TRVs are set low, the pump will deadhead.

The proper way is to use a Differential Pressure Regulator. It is explained in this Text on page 20 thru 21
http://media.blueridgecompany.com/documents/ZoningMadeEasy.pdf

hotsauce

Jamie Hall said:

If you are using TRVs, then you only need one thermostat in the coldest room. You might need a delta P pump or some sort of bypass so the boiler maintains circulation in the odd circumstance that the thermostat is arguing with the TRV in that room and calls for heat with all the TRVs closed.

Or you could wire three thermostats in parallel to run the circulator and the boiler -- but you still will need either the delta P pump or a bypass to protect the boiler if all the TRVs are closed but a thermostat is calling. Which, by the way, WILL happen sooner or later.

Thanks Jamie! My boiler feeds a buffer tank with a separate circulator so that the boiler stays in the condensing zone. The thermostats will only control the secondary circulator that pumps between the buffer tank and the three (currently) unheated rooms.

hotsauce

EdTheHeaterMan said:

I think I understand what you want to accomplish, but it won't work. You want to stop the circulator from deadheading when all three TRVs are closed. You want the thermostats to do that. But you want the TRVs to keep the "Other Rooms" whichever ones they may be, to keep the room from overheating.

Sounds like a good theory, however a room thermostat can be set to 80° by someone who does not understand the concept (I know ... that will never happen... until it does and you destroy a circulator pump 5 or 10 years from now). If any thermostat calls for heat and all the TRVs are set low, the pump will deadhead.

The proper way is to use a Differential Pressure Regulator. It is explained in this Text on page 20 thru 21
http://media.blueridgecompany.com/documents/ZoningMadeEasy.pdf

Agreed, and that was my biggest concern with this approach. Don't some of the newer Delta pumps have built in deadhead protection?

ratio

I think you want a ΔP circ. It's my understanding (however I could be wrong) that deadheaded they'll ramp down until they're paddling the water just enough to notice if a valve opens.

hotsauce

ratio said:

I think you want a ΔP circ. It's my understanding (however I could be wrong) that deadheaded they'll ramp down until they're paddling the water just enough to notice if a valve opens.

That would be awesome! I have been looking at the Alpha and the 006. I have to go back and review them more closely and I posted this thread to see if there was anything else I overlooked!

Solid_Fuel_Man

Use an Alpha 1, the 15-55 is what fits most typical residential zones. 

They can be deadheaded, I have 3 of them and set on speed 1 they will operate from anywhere between 43 watts and 5 watts depending on the flow allowance (valves open). 

hotsauce

Solid_Fuel_Man said:

Use an Alpha 1, the 15-55 is what fits most typical residential zones. 

They can be deadheaded, I have 3 of them and set on speed 1 they will operate from anywhere between 43 watts and 5 watts depending on the flow allowance (valves open). 

Thanks! Why not the Alpha2?

Solid_Fuel_Man

Yes, the Alpha2. I'm sorry I didn't have my coffee when I wrote that. 

Set to AutoAdapt. The Alpha1 is 3 constant speeds better for boiler circulator or radiant without actuators. 

EdTheHeaterMan

I this is true...
Then you dont need a thermostat. you just need outdoor reset to operate the burner.