Ascent Combi & Ascent Plus Combi Gas Heat
– PN 10-2099 – May 2020
6
ASCENT COMBI and ASCENT PLUS COMBI BOILERS
IMPORTANT MESSAGE TO HOMEOWNER: These instructions should be carefully read and kept for future
reference to gain the best performance from your Ascent Combi or Ascent Plus Combi boiler.
CONGRATULATIONS ON YOUR PURCHASE OF THE ASCENT COMBI or ASCENT PLUS COMBI boiler with its
highly efficient low mass hydronic heat exchanger, advanced learning control, and integrated hot water production. It
is the product of years of engineering and advanced design, which brings together in a single system all elements
needed to provide efficient home heat. This operation and maintenance information has been prepared so that you
may better understand and use your Energy Kinetics Ascent Combi or Ascent Plus Combi Boiler and Heating System.
The Ascent Combi and Ascent Plus Combi boilers basically consist of a heat source (gas burner with control), an
energy converter, piping, sheet metal chassis and outer covers. For a typical residence, the installation may include a
circulating water pump external zone control, and integrated domestic hot water production with ASSE 1017 point-of-
source mixing valve. For any questions about installations not already explained within this manual, consult Energy
Kinetics Customer Service.
ASCENT COMBI and ASCENT PLUS COMBI BOILERS - PRINCIPLE of OPERATION
The Ascent Combi and Ascent Plus Combi boilers are combination heat and hot water systems. These boilers are
provided with TT terminals for connection of a thermostat for heat calls and contains an integrated flow switch to
indicate hot water flow. Upon a call for heat and/or hot water, the boilers will fire as needed to provide the required
heat and hot water temperatures. In the case of a simultaneous heat and hot water call, the boilers will give
preference to the hot water production.
The Ascent Combi and Ascent Plus Combi boilers have 4 user-selectable modes of operation to control how the
boilers behave in between active heat and/or hot water calls:
Option 1 (OP1)
– Maintain Temperature – Good Efficiency, Best Hot Water Convenience
Option 2 (OP2)
– Cold-start On Demand Hot Water – Best Efficiency, Good Convenience
Option 3 (OP3)
– Advanced Learning – Better Efficiency, Better Convenience
Option 4 (OP4)
– Advanced Learning – Better Efficiency, Better Convenience - For inconsistent schedules
Option 1 (OP1): The EK1T Ascent Combi and the EK1T+ Ascent Plus Combi ship in the least efficient mode, Option
1, or OP1. In this mode, the boiler will maintain a minimum temperature (factory set to 145°F) to ensure hot water can
be instantly produced at all times. This is similar the way traditional tankless coil boilers operate although they
typically maintain significantly higher temperatures than are required by the EK1T Ascent Combi and the EK1T+
Ascent Plus Combi. Even in this setting, significant savings over traditional tankless coil boilers will be realized.
Option 2 (OP2): This mode is much more efficient and the boiler operates as a cold start system for heat and hot
water. The boiler will not maintain temperature (although it may be hot for a large portion of the heating season) and
may not always be able to instantly produce hot water. A hot water draw of at least 30 seconds will enable the boiler
to fire. The boiler will take roughly 2-3 minutes to reach full operating temperature, during which the boiler will send
out progressively warmer pulses of water as part of its preheat and condensation protection operation. To speed
preheating and reduce water use, the boiler can be activated instantly with a “double pump”: Turn the hot water on
and off twice in quick succession at any fixture in the house. The boiler will recognize this as a requirement to preheat
and quickly get ready to make hot water. With a “double pump,” the hot water fixture can be left off and the boiler will
preheat. The Ascent Combi is well insulated and will remain hot for over 2 hours after preheating, so after activated,
the water will be ready for an extended period of time.
Option 3 (OP3): This option is a compromise between maximum efficiency and convenience. In this mode, the
boiler will learn your schedule over the course of two weeks. The boiler will automatically preheat anytime your usage
pattern indicates a hot water draw may be imminent. This mode will use more fuel than OP2, however it will provide
significant savings over OP1 as long as your schedule is reasonably consistent. If the boiler does not correctly
anticipate your schedule, the same draw patterns as OP2 will activate the boiler (30 second draw or cycling the hot
water faucet twice in succession).
Option 4 (OP4): This option is a compromise between maximum efficiency and convenience. Like Option 3, in this
mode, the boiler will learn your schedule over the course of two weeks in particular by identifying periods with no hot
water demand like night time hours. The boiler will automatically preheat anytime your usage pattern indicates a hot
water draw may be imminent based on any usage in the past two weeks. This mode will use more fuel than OP2 and
OP3, however it will provide savings over OP1 and is ideal if your schedule is less consistent. If the boiler does not
correctly anticipate your schedule, the same draw patterns as OP2 will activate the boiler (30 second draw or cycling
the hot water faucet twice in succession).
NOTE: Cold-start, OP2, should be selected for Heat-Only installations.
