front door, where the burner is located. By using flexible
lines instead of hard pipe, service techs can open the
boiler without removing the fuel fitting at the burner.
“Providing deaeration is even more critical on a multiboiler
installation like this because, the more times you
tee off of the fuel line, the more opportunity there is for
air to enter the fuel supply,” continued Walker.
Venting the boilers was done as deliberately as supplying
the fuel. The existing chimney was large enough,
but common venting the three units had to be done
carefully.
“We couldn’t just run three, six-inch vents into a
common stack, because the distance between the boilers
and the main stack were slightly different,” explained
Henderson. “The first two boilers join into an eight-inch
vent, which increases to 10 inches as it picks up the
third boiler and exits to the chimney.”
Control
When the original boiler failed, the property owner
decided that he wanted to monitor the heating system
regardless of where he was, and he also made the decision
to sign a service agreement with Summers & Zims.
For both of those reasons, Henderson wanted to find a
control solution to stage the boilers and provide webbased
monitoring; they also wanted to avoid the use of a
complex, costly building automation system.
“Jason had recently told us about the new tekmar 294,”
said Walker. “So when we bought the boilers from Hajoca,
we also bought the control. The 294 is similar to the 274,
but with more features, a touch screen, and most importantly,
remote monitoring capability. It can also send me texts,
emails and push notifications for a wide variety of alerts.”
The control stages and rotates the boilers, as well as
handles outdoor reset, domestic hot water (DHW) priority,
warm weather shutdown, etc. In a typical MPO-IQ boiler
installation, the onboard boiler control features optional
plug-and-play cards to provide outdoor reset, low-water
cutoff and aquastat. In this system, the tekmar 294 replaces
all but the low-water cutoff card.
“The 294 was easy to install, and I can pull up and make
setpoint changes to the customer’s system at my office or on
my phone,” said Walker.
Within a week of the old boiler failing, the new hydronic
system was heating the building, and the pool heater was
turned back down to its normal operating temperature.
This job—and the speed at which it came together
despite supply chain issues—is a testament to contractors
like Summers & Zims, who show up and do the very best
they can. ICM
Installations
10 ICM/September/October 2022