This project involved four adjacent buildings housing seven commercial spaces and 14 residential spaces. The developer initially wanted copper fin tub radiators, but quickly saw the advantages of the increased comfort and reduced heating bills with radiant heat. The developer will be paying all of the gas bills for the heating and hot water production.
She was able to get free boilers from Keyspan so she supplied the boilers. We suggested Tekmar outdoor reset controls with Tekmar 4-way mixing valves. We also suggested Heatlink for all of the Radiant work.

We provided a Tekmar 363 microprocessor to control all aspects of heating and hot water production. The Tekmar 363 controls the boiler, the production of domestic hot water and the four-way mixing valve. With this mixing valve we can fully modulate the temperature of the water going to the spaces. This results in a 35% fuel savings over conventional piping. This control senses the outdoor temperature and adjusts the temperature of the supply water accordingly. In this way it only delivers as much hot water as is needed to heat the apartments. On only a very few days of the year do you need the maximum output of the boiler. With this control we run the pump continuously during the heating system and just adjust the temperature of the water going to the spaces. Thus the system is comfortable, quiet, and very fuel-efficient.


PICTURE #1 shows the Tekmar mixing valve (#1); Grundfos pumps (#2); Heatlink pressure by pass valve (#3); Rigid propress fittings (#4)

We always use Ridgid Propress fittings for all of our hot water boiler piping. They make stronger connections than normal sweat fitting and reduce the possibility for any leaks.

PICTURE #2 shows the Supply and Return manifolds in the boiler room.

The ball valves and hose valves allow us to fill the system with water and purge all air right from the boiler room. The ball valves allow us to service each apartment without turning off the heat to any other apartment.

PICTURE #3 is a larger version of picture #2

We used ¾” PEX tubing from Heatlink to carry the hot water for heating both to and from the Heatlink manifolds in each apartment. (See picture #4) We did neaten up the vertical Pex runs before we finished up the job.

See (#1). This is one of the real cool things about using radiant heat for your project. In the lower right hand corner of the picture you will see a 30-gallon electric hot water heater. We used this HWH to heat the entire building through the entire winter because we could not get the utility to turn the gas on until the spring. All of the workmen said that this was the most comfortable building they had ever worked in during the winter. The owner was thrilled that nothing would freeze and that the work could continue through the cold winter months.

PICTURE #4 shows the Heatlink manifolds that are installed in each apartment.

The ¾” Heatlink Pex tubing on the right comes from the boiler. They feed the Heatlink manifold which then distributes the water to the five ½” Heatlink Pex tubing loops that go into the cement floor.
Each apartment is able to control it’s own heat with a thermostat that controls a zone valve (#1)

PICTURE #5 shows the Jazz indirect tank manufactured by the Tam Corporation. Indirect Domestic Hot Water Tanks

The best way to make domestic hot water today is with the indirect method. It is like making hot water and storing it in a thermos bottle so that you have it when you need it. This tank loses very little heat when not in use. These tanks are made entirely of stainless steel and the coil is stainless steel as well. It is the same quality of stainless steel used in military tanks so it is very strong. It is because of this superior construction that these tanks are guaranteed for 15 years by the manufacturer.

We would take the hot water from your boiler and pass it through the stainless steel coil inside this Jass tank and thus heat the domestic hot water. We would install a Grundfos self-lubricating circulating pump on the boiler circuit and an aquastat on the tank. We would insulate all the new water piping with 1/2" rubber insulation. We would repipe the existing hot water and cold water lines from the old hot water heater to the new indirect tanks. With this indirect method the boiler only comes on when you need it to come on because you have your hot water in your thermos bottle. This is the heart of the fuel savings.