Controls
The Raypak modulating temperature control is pro-
vided to maintai n the desired syst em water
temperature. The control has various modes of opera-
tion which are described on the following pages.
The XTherm is desi gned for use with
Primary/Secondary pumping only, utilizing integral
injector pumps to maintain proper flows and tempera-
tures in the heater.
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. 34.
32
CAUTION: Risk of electric shock: More than one
disconnect switch may be required to de-energize
the equipment before servicing.
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.
Fig. 32: Adapter Thimble
Crimp end to be installed into termination cap.
Fig. 33: Termination using Adapter Thimble
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: Turnoff the power to the heater before
installation, adjustment or service of any heater
controls. Failure to do so may result in board
damage, heater mal function, propert y damage,
personal injury,or death.