X-FIRE 300A-850A, Инструкция по установке и эксплуатации

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The following applications are approved configurations
supported by Raypak for CWP systems.
Cold Water Protection: H models -
Closed Loop
Closed loop heating systems that will experience
extended and/or repeated warmup periods where the
inlet water temperature remains below 50ºF (10ºC)
lasting more than 7 minutes must have cold water
start protection . Known protection methods consist
of mixing heated outlet water with the inlet water using
a fixed - manual bypass to raise the inlet to 50ºF
(10ºC) or higher. Once the system is heated up and
has return water temperatures of 50ºF (10ºC) or high-
er, the mixing of outlet water with inlet water is no
longer needed and the bypass can be shut off. If the
bypass is not shut off as the system heats up, the out-
let temperature may continue to climb and trip the high
limit, thereby shutting down the heater. Thus an auto-
matic valve system, such as a three-way proportional
valve to control the bypass should be used. The
Integrated VERSA IC control system provides auto-
matic functionality to control a proportional 3-way
valve to provide cold water protection for a single unit
or multi-unit cascade configuration. For more informa-
tion regarding this function see VERSA IC manual,
catalog 5000.72.
Cold Water Protection: H and WH
models - Open Loop
With open loop systems, typically a variable-flow injec-
tion system will be used in lieu of a 3-way proportional
valve to provide cold water protection. This is done to
avoid wide swings in flow rate to and from the heater
that can be experienced with a 3-way valve. This in
turn can cause elevated temperature differentials
between the heater inlet and outlet which can lead to
potential scale formation. For potable water systems
requiring low lead construction there are very few
options for a 3-way valve that meets this requirement
so the preferred method is an injection loop. An injec-
tor pump approach has the added value of being able
to adjust very quickly to changes in the system water
coming back to the heater. The integrated VERSA IC
control system provides functionality to control a single
variable flow injection system. For more information
regarding this function see VERSA IC manual, catalog
5000.72.
14
Hydronic Heating
Pump Selection
In order to ensure proper performance of your heater
system, you must install a correctly-sized pump. Ray-
pak recommends designing for a ∆T within the range
of 15°F to 35°F (8°C to 19°C). See Table H for accept-
able flow rates for each model (∆T is the temperature
difference between the inlet and outlet water when the
heater is firing at full rate).
Raypak standard pump selection for H models is
based on a 30º ∆T, and allows for up to 75 equivalent
feet of tubing between the boiler and the system con-
nections.
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
Boiler Model
Standard Boiler Pump*
Pump HP
H7-300A 0012 1/8
H7-400A 0012 1/8
H7-500A 1611 1/4
H7-700A 1630 1/2
H7-850A 1630 1/2
Table G: Pump Selection
* Pump selection based on 30° ∆T with up to 75 eq. ft. of tubing.
CAUTION: Damage due to internal condensation
may occur if the heater inlet water temperature does
not exceed 50ºF (10ºC) within 7 minutes of startup.