15
Leaks must be repaired at once to prevent damage to
the heater. NEVER use petroleum-based stop-leak
compounds.
Toperform hydrostatic test:
1. Connect fill water supply. With bleed valve open,
fill heater with water.When water flows from bleed
valve, shut off water. Close bleed valve. Carefully
fill the rest of the system, making sure to eliminate
any entrapped air by using high-point vents. Close
feed valve.Test at standard operating pressure for
at least 24 hours.
2. Make sure constant gauge pressure has been
maintained throughout test.
3. Check for leaks. Repair if found.

Raypak Integral Cold Water

Protection

XTherm heaters are equipped with an integral cold
water protection system. Units equipped with the dual
injector pump system are designed to operate with
heater inlet water temperatures down to 50°F continu-
ous. Under start up conditions the dual injector system
can operate with fluid temperatures down to 32°F.
Operation at lower temperatures will create unwar-
rantable damage to the injector pumps. XTherm WH
and WHP models equipped with single injector pumps
are designed for typical domestic hot water and com-
mercial pool heating operating conditions respectively.
Contact your local representative or the factory for
applications assistance.
Hydronic Heating

Pump Selection

The heater is equipped with an integral cold water pro-
tection system that includes dual modulating injector
pumps to pull the required flow from the system loop
and a heater pump, sized by the factory, for the opti-
mal T across the primary heat exchanger. The
systemis designed forcontinuous return temper atures
from 50°F to 180°F.
CAUTION: Damage due to internal condensation
may occur if the heater inlet water temperature does
not exceed 50°F (22°C) within 7 minutes of start-up.

Feedwater Regulator

Raypak recommends that a feedwater regulator be in-
stalled and set at 12 psi minimum pressure at the
highest point of the system. Install a check valve or
back flow device upstream of the regulator, with a
manual shut-off valve as required by local codes.

Piping

All high points should be vented. A heater installed
above radiation level must be provided with a low wa-
ter cut-off device (sales order option F-10). This
heater, when used in connection with a refrigeration
system, must be installed so that the chilled medium is
piped in parallel with the heater with appropriate
valves to prevent the chilled medium from entering the
heater.
The piping system of a hot water heater connected to
heating coils located in air handling units where they
may be exposed to circulating refrigerated air,must be
equipped with flow control valves or other automatic
means to prevent gravity circulation of the heater
water during the cooling cycle. It is highly recommend-
ed that the piping be insulated.

Air-Separation/Expansion Tank

All heaters should be equipped with a properly sized
expansion tank and air separator fitting as shown in
Fig. 13.

Three-Way Valves

XTherm heaters have an integral cold water protection
system to maintain required temperatures and flow
rates.
Fig. 13: Air-Separation/Expansion Tank
WARNING: Three-way valves intended to regulate
system water temperatures by reducing flow in the
boiler should not be used.