Lochinvar 000 - 500 사용자 설명서

This piping is like a primary/secondary boiler
installation with a bypass in the secondary boil 

er

piping.  Inlet water temperatures below 140°F  (60°C)
can excessively cool the prod 

ucts of combustion

re sult ing in condensation on the heat exchanger and in
the flue.  Condensation can cause operational prob lems,
bad combustion, sooting, flue gas spillage and reduced
service life of the vent system and related components.
The bypass allows part of the boiler discharge water to
be mixed with the cooler boiler return water to in crease
the boiler inlet temperature above 140°F  (60°C).  This
should prevent the prod 

ucts of com 

bus 

tion from

condensing in most in stal la tions.  The bypass should be
fully sized with a bal anc ing valve to allow for proper
adjustment.  A valve must also be provided on the boiler
discharge, after the by 

pass.  Closing this discharge

valve forces water through the bypass.  Start boiler
adjustment with the bypass valve in the full open
position and the boiler discharge valve half open.  A
small amount of the high er temperature boiler discharge
water is mixed with the system water to maintain the
de sired lower system tem per a ture. A remote low tem -
per a ture range operator is recommended to control the
boiler operation based on the lower system tem per a ture.
This remote op er a tor should be wired across the R and
W terminals (see Room Ther 

Terminal Strip Instructions).

The installation of a three way valve on this boiler is not
generally recommended because most piping meth ods
allow the three way valve to vary flow to the boil er.
This boiler is a low mass, high ef fi cien cy unit which
requires a constant water flow rate for proper op er a tion.

Low flow rates can re sult in overheating of the boiler
water which can cause short burner on cycles, system
noise and in extreme cases, a knocking flash to steam.
These conditions can cause operational prob lems and
non-warrantable failures of the boiler.  If a three way
valve must be installed, please pipe in a
primary/secondary system as shown in Figure 45.
Based on boiler sizing and system flow requirements,
this piping may still result in boiler short cycling. 

The heat exchanger is generally capable of op er at ing
within the flow rates of a residential heating system.
Should the flow rate exceed the maximum allowable
flow rate through the boiler (30 GPM) an external
bypass must be installed.  The bypass should be fully
sized with a balancing valve to al 

low for proper

ad just ment of flow.  Flow rate can be determined by
measuring the temperature rise through the boiler. 

The basic guide for minimum flow in this boiler is
based on a 40°F temperature rise in most in stal la tions.
Low er flow and a higher temperature rise is acceptable
if the boiler system is specifically de 

signed for the

char ac ter is tics  of  a  higher  tem per a ture  rise.    A  system
not specifically designed for a higher temperature rise
may experience over heat ing of the boiler water.  This
can cause short burn er on cycles, system noise and in
ex 

treme cases, a knocking flash to steam.  These

con 

di 

tions can lead to operational problems and

non-war 

rant 

able fail 

ures of the boiler.  High

temperature rise systems must be designed by a
qualified engineer.

The maximum flow rate through the boil er with a
copper heat exchanger must not ex ceed 30 GPM. 

 CAUTION

MAKE-UP WATER

PRV

EXPANSION TANK

FROM SYSTEM

BYPASS VALVE

AIR SEPARATOR

SYSTEM PUMP

TO SYSTEM

LWCO
(OPTIONAL)

SECONDARY 
BOILER PUMP

FROM
SYSTEM

THREE-WAY VALVE
SLOW 
OPENING/SLOW
CLOSING

EXPANSION
TANK

PRV

MAKE-UP
WATER

AIR SEPARATOR

SYSTEM PUMP

TO SYSTEM

LWCO
(OPTIONAL)