Design Build Hydronic Heating System in Browns Point, Tacoma, WA
Service: Hydronic Heating Systems
Location: Tacoma, WA
This Particular Residence, was originally Constructed in the mid 1960’s, and was heated by a cast iron
hydronic boiler system with baseboard radiators on both the upper and lower levels.
We were brought in originally by the new owners to provide some options to install modern European
style baseboard radiators to replace the rather unsightly old copper/fin tube style radiators that had
been in place for well over 50 years.
Due to supply chain issues the European style radiators proved to be a very costly option, and we
worked with the homeowners to come up with a cost saving alternative, which ultimately provided
them with a solution they were far happier with, from both the perspective of cost, as well as styling and
performance.
The solution was to convert the upper floor to in‐floor radiant heat and utilize the existing radiators on
the lower floor, with custom hardwood covers that the homeowners intend to design and build
themselves. It just so happens that they are highly skilled wood workers.
To minimize their out of pocket costs, we provided a design layout for the in floor piping loops and gave
them eight hours of assistance and training on how to install the floor loop pex piping runs themselves.
Traditionally the loops would be secured to the subfloor and a layer of gyp‐crete would be poured over
them, providing the needed thermal mass and a smooth surface for the installation of the final flooring
material. In this case they elected to utilize plywood strips between the tubing runs with aluminum heat
transfer plates, and intend to install tile, carpeting, and hardwood over the top of it all to finish it off.
Having radiators and in‐floor heat runs on the same system poses some challenges from the perspective
of the water temperature being supplied to them, as radiators require much hotter water then in‐floor
systems are willing to tolerate. Further challenges included a boiler that would now be significantly
oversized, which they did not want to replace as it had just recently been replaced by the previous
homeowner.
The solution to overcome these challenges was met by our design engineer by utilizing an indirect
water heater that was coupled to the boiler and keeping the water temp in its holding tank at the
temperature required by the radiators, and then installing mixing valves on the in‐floor loop manifolds,
we would be able to prevent the boiler from short cycling due to the large volume of water in the
indirect tank, and also keep the floor loops down at a reasonable temperature where it would be
comfortable for the occupants and would have any worries of buckling the floor systems.
The mechanical room where the boiler was located also posed some challenges as the only possible
location for the indirect water heater was on the opposite end of the room from the boiler. This meant
that the pumping package and manifold assemblies would be sandwiched in‐between the boiler and the
tank, thereby making for a lot of back and forth piping. The only solution to this was to pre‐plan as best
we could all of the piping runs, using the closest thing we had available to virtual reality, which ended up
being a lot of AutoCad drafting .
The end result of all of the combined effort ending up providing these homeowners with the heating
system they have always wanted at a price that fit into their budget, and added significantly more value
to their property, then that of their out of pocket costs.
See project photos below.
Plywood Strips prior and post piping work, note the aluminum heat transfer plates which help spread
the heat out evenly through the floor system.
In shop pre‐fab of the circulator and manifold assemblies, note the blue knobs are the adjustment
controls for the mixing valves associated with the in‐floor piping loops.
The circulator and manifold assembly installed in the boiler room. Note that this assembly was shipped
as a completed unit to the project site and installed as one piece, minus the horizontal pipe runs at the
top of the assembly, which provide the inter‐connections between the boiler, the indirect water heater
and the circulating/manifold system.
Photo of indirect water heater which was utilized to prevent boiler short cycling, and in conjunction with
the mixing valves helps to manage the differing water temperatures that were needed throughout the
system.
Thank you for taking to review this Project Spotlight and please reach out to us if your thinking of
installing a hydronic heating system or any other type of heating or cooling needs you might have.
Products Used
Uponor, Grundfoss, Taco, Honeywell, Weil Mclane
