Install Instructions

ManualsBrandsTekmar ManualsHeating SuppliestekmarNet 4 Thermostat - Two Stage Heat, Two Stage Cool, Two Fan

32 of 48

A Watts Water Technologies Company

Warm Weather Shut Down

--------------------------------------------

When the outdoor air temperature exceeds the Warm Weather Shut Down (WWSD)

setting on the tekmarNet

main control, the heating system is shut off.

A W1 HEAT WWSD setting is available to allow the heat pump to heat the building

while the radiant floor heat system is shut off during mild outdoor temperatures. This

is advantageous in the spring and fall when heating is required at night and cooling is

required during the day. As the outdoor temperature falls below the W1 HEAT WWSD

setting, the radiant floor becomes the primary heat source and the heat pump provides

supplemental heating.

Balance Point

-------------------------------------------------------

An air source heat pump’s Coefficient Of Performance (COP) decreases with colder

outdoor temperature. This affects the heating output capacity of the heat pump to

heat the building. When the COP is equal to 1, the heat pump no longer provides an

economic advantage over electric heating elements or other supplemental heating fuel.

The outdoor temperature at which this occurs is known as the balance point. When

the outdoor temperature falls below the balance point, the heat pump is shut off and

the backup supplemental heat source is operated to heat the building. The 557 has

the ability for the balance point setting change based upon a programmable schedule.

This is useful in cases where the electrical utility offers lower different energy pricing

throughout the day.

Backup W2 Differential

-----------------------------------------------

The backup heat source operated by W2 has an adjustable differential. The differential

is relative to the previous heating stage.

No radiant floor heating, no heat pump (no W1, no Y1, no Y2)

The W2 relay’s differential is ±1

°F (0.5°C) centered around Set Heat.

Radiant floor heating, no heat pump (W1, no Y1, no Y2)

The W2 relay turns on at Set Heat - Backup Differential.

Single Stage Heat Pump (W1, Y1, no Y2)

The W2 relay turns on at Set Heat - 1°F (0.5°C) - Backup Differential.

Two Stage Heat Pump (W1, Y1, Y2)

The W2 relay turns on at Set Heat - 1°F (0.5°C) - Y2 Differential - Backup Differential.

Freeze Protection

----------------------------------------------------

The thermostat operates the heat whenever the room or floor temperature falls below

40°F (4.5°C) even when the mode is set to off.

Cooling Operation

Section B

Set Cool Temperature

-----------------------------------------------

The 557 can operate a two-stage heat pump or air conditioner to provide cooling

depending on the outdoor air temperature. In some cases, cooling is provided by a

chilled water fan coil. The illustration below shows when each of the available cooling

units are available. The “Cool On” symbol is shown on the display when the thermostat

is cooling.