Takagi tankless for hydro air system

James_5

I want to use a Takagi t-M1 tankless water heater as a boiler. The HVAC company has installed 2 high velocity a/c units with hot water coils. The 600 cfm units each have a capacity of 59.4 MBH with a water flow of 4 GPM up to 62.4 MBH with a water flow of 8 GPM. Both are rated with entering water @ 180 degrees.

The third conventional unit is not installed yet but I assume the specs will be similar. The heat loss on the house in the area that these 3 units service is 173,000 BTU's.

There is also 8 loops of radiant in the floor of the 1100 SQFT basement which has a stone foundation and is 6' underground.

I would like to use the 235,000 BTU Mobius T-M1 Takagi tankless water heater to power the system. It can put out 4 GPM at 180 degrees or 5.6 GPM at 140 degrees with incoming water temp at 70 degrees.

When I do the math I find that the leaving water temp of one unit is 150 if I put in water temp at 180 (water temp loss is 29.7 degrees). Since I have three units that would be a total temp lost of 89.1 degrees. So the water comes into the T-M1 at 90.9 degrees and is reheated to the 180 which is within the enter at 70, leave at 180, T-M1 rating.

The questions are 1.is this going to work? 2.would the Takagi be running all the time and fail do to heavy duty cycle? I would appreciate you expert feed back Thanks

James_5

Takagi tankless for hydro air system

I want to use a Takagi t-M1 tankless water heater as a boiler. The HVAC company has installed 2 high velocity a/c units with hot water coils. The 600 cfm units each have a capacity of 59.4 MBH with a water flow of 4 GPM up to 62.4 MBH with a water flow of 8 GPM. Both are rated with entering water @ 180 degrees.

The third conventional unit is not installed yet but I assume the specs will be similar. The heat loss on the house in the area that these 3 units service is 173,000 BTU's.

There is also 8 loops of radiant in the floor of the 1100 SQFT basement which has a stone foundation and is 6' underground.

I would like to use the 235,000 BTU Mobius T-M1 Takagi tankless water heater to power the system. It can put out 4 GPM at 180 degrees or 5.6 GPM at 140 degrees with incoming water temp at 70 degrees.

When I do the math I find that the leaving water temp of one unit is 150 if I put in water temp at 180 (water temp loss is 29.7 degrees). Since I have three units that would be a total temp lost of 89.1 degrees. So the water comes into the T-M1 at 90.9 degrees and is reheated to the 180 which is within the enter at 70, leave at 180, T-M1 rating.

The questions are 1.is this going to work? 2.would the Takagi be running all the time and fail do to heavy duty cycle? I would appreciate you expert feed back Thanks

Louie

Not Takagi

James, If you want a water heater-boiler that will
only be on demand try Teledyne-Laars. They have very well made copper fin-tube units that might fit your needs. Laars.com Good luck.