PV 6619 9/02
2
SPECIFICATION FOR DOMESTIC WATER HEATERS
Semi-instantaneous, U-tube, Hot Water Generators with Nickel-Plated Shell
And Steam as the Energy Source
(continued)
Outlet Water Temperature Controls
Inlet steam through the heat exchanger will be controlled by one or more on/off, solenoid valves that respond to an
immersion thermostat. Solenoid valve(s) will fail closed to prevent a runaway situation in the event of a power
interruption. The solenoid valve(s) offer a “built-in” solenoid shutoff for the inlet steam in the event of an over-
temperature situation. The semi-instantaneous heater will contain enough stored water to act as a temperature buffer
and will enable control of outlet water temperature to within 5°F of thermostat setting without the need for a continuously
running integral circulating pump or a modulating steam valve connected to a feed-forward blending system. An over-
temperature tank purge valve will not be required as standard equipment to correct for temperature swings.
The heat exchanger will be sized to obtain the required domestic water temperature and flow through the significant
latent energy in steam that is released as it condenses. The heater will not need to sub-cool condensate. For maximum
boiler system efficiency, condensate will return at above 200°F, eliminating the need to reheat condensate prior to re-
introducing it into the boiler.
Safety Controls
As a minimum, the heater will be equipped with the following:
•
automatic solenoid shutoff of inlet steam line
•
an
immersion
operating thermostat
•
an
immersion
temperature limiting device
•
an ASME- or AGA-rated temperature and pressure relief valve
If selected, the water heater will be equipped with the following optional equipment.
____ manual-reset , temperature limiting device
____ double-solenoid, over-temperature system with tank purge valve
____ a pressure differential, tube wall breach detection and shutdown system
Warranty Summary
Heat exchanger will have a ___ one-year ____ three-year warranty. All other heater parts will have a one-year
warranty. Storage tank will have a ten-year
warranty covering manufacturing or material defects, and/or the production of
rusty water. If indicated here, the heater will also have a _____ first year or ____ long-life service policy, which will cover
replacement labor and freight costs under certain conditions. This summary is not a warranty. Consult warranty and
policies for full details.
Complete copies of all warranties and service policies, including all exclusions and
conditions, will be presented to the owner as part of the submittal package.
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