Raypak 503-2003 manual Controls, Freeze Protection, Operating Modes

NOTE: Condensate can freeze on the vent cap. Frozen condensate on the vent cap can result in a blocked flue condition.

Fig. 29: Outdoor Venting

Freeze Protection

CAUTION: Risk of electric shock: More than one disconnect switch may be required to de-energize the equipment before servicing.

The Raypak modulating temperature control is pro- vided to maintain the desired system water temperature. The control has various modes of opera- tion which are listed on the following pages.

Setpoint: The intended system supply temperature.

Deadband: Deadband is a band of temperature sens- ing where no action occurs. All temperature controllers have a deadband and the purpose is to prevent short- cycling of the heater. The on-board temperature controller has a deadband of 2ºF around the differen- tial.

Differential: A heat source must be operated with a temperature differential in order to prevent short- cycling. The temperature differential is divided around the “target” temperature or set-point. The Call For Heat (CFH) contact will close in the controller when the water temperature is below the target temperature by 1/2 of the differential setting, and will open when the water temperature is above the target temperature by 1/2 of the differential setting. See Fig. 30.

The Raypak electronic temperature control includes a freeze protection feature. In the event the temperature drops below 40°F at any of the boiler temperature sen- sors, the pump is turned on and will remain on until the temperature at all boiler sensors rises to 45°F.

Controls

WARNING: Installation, adjustment and service of heater controls, including timing of various operating functions, must be performed by a qualified installer, service agency or the gas supplier. Failure to do so may result in control damage, heater malfunction, property damage, personal injury, or death.

WARNING: Turn off the power to the heater before installation, adjustment or service of any heater controls. Failure to do so may result in board damage, heater malfunction, property damage, personal injury, or death.

CAUTION: This appliance has provisions to be connected to more than one supply source. To reduce the risk of electric shock, disconnect all such connections before servicing.

30

Fig. 30: Differential Graph

Operating Modes

Mode 1 (Not supported) – Setpoint operation using primary piping. The heater outlet water temperature is controlled to the boiler target setpoint.

Mode 2 – Setpoint operation using primary/secondary piping. The control operates the heater to satisfy a remote system sensor. The heater is turned off based on boiler max and boiler differential (factory default). See Fig. 31.