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
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
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
PICTURE #4 shows the Heatlink manifolds that are installed in
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)
#5 shows the Jazz indirect tank manufactured by the Tam Corporation.
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.
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.