Product Brochure

The three-function Fuel Smart HydroStat is factory equipped on many premier

boiler lines. It is also available at leading plumbing & heating wholesalers for upgrading

existing gas and oil ﬁred boilers with fuel-saving Boiler Reset Functionality.

Optional Features

Easily activated in HydroStat’s program mode

Thermal Pre-Purge – Further enhances boiler efﬁciency by supplying latent heat, that may remain in the boil-

er from a previous run cycle, to the heating zone requiring heat. The control activates the burner only when

it determines that the latent heat will not be adequate to satisfy the heating demand. During the Pre-Purge

cycle, the display will indicate .

Degrees Celsius – Changes the control’s settings and display to Celsius.

Manual Reset LWCO – Changes the low water cut-off function to manual reset, which is required for many

commercial installations.

Circulator Activation – Can be set to activate the primary circulator on calls from T/T, ZC/ZR, or both.

Enhanced Condensing Protection – To reduce the potential for condensing, on a call for heat, this feature

allows the boiler to heat to 125°F prior to energizing the circulator. Once activated, the control continues to

monitor boiler temperature and interrupts the circulator if it drops below 115°F.

Fuel Savings through Boiler Reset

Boiler Reset is the decades-old principle of governing boiler temperature in accordance with the heating de-

mand. A boiler is sized to heat a home during the coldest days of the year. During all other times, the heating

system is larger than it needs to be. Boiler Reset saves fuel by reducing the boiler temperature during peri-

ods of non-peak demand. The FuelSmart HydroStat offers two cost effective ways to provide this fuel saving

technology:

Thermal Targeting™ – Microprocessor based algorithm monitors thermostat activity and continually eval-

uates how much heat the house requires. When demand for heat is high the FuelSmart HydroStat raises

the boiler’s Target Temperature to provide needed heat to the house. When demand for heat is lower the

FuelSmart HydroStat lowers the boiler’s Target Temperature – saving fuel – while continuing to provide

comfort to the house.

Outdoor Reset & Warm Weather Shutdown – For those who prefer the more traditional outdoor reset ap-

proach, Hydrolevel offers two Outdoor Sensor Kits (see below). When sensor is plugged into the control,

the boiler reset methodology changes instantly from Thermal Targeting to Outdoor Reset, where the boiler

temperature is governed by the temperature outside. Use of sensor also allows the control’s Warm Weather

Shutdown feature to be activated. This feature prevents the boiler from supplying space heating when the

outside temperature exceeds a selected level.

Outdoor Sensor Kits (sold separately)

Hydrolevel’s optional Outdoor Sensor Kits automatically activate outdoor reset functionality and warm

weather shutdown capability when used with the

HydroStat-Plus control. These easy-to-install kits

are available at Hydrolevel distributors.

Part No. Description

48-140 Model OS-100 Outdoor Sensor Kit

48-145 Model OS-200 Wireless Outdoor Sensor Kit

MODEL OS-100

MODEL OS-200