FläktGroup LQES Air heater, stream Installation guide

FläktGroup
Brand
FläktGroup
Model
LQES Air heater, stream
Type
Installation guide
FläktGroup DC_9148GB 20180412_R0
Specifications are subject to alteration without notice
INSTALLATION INSTRUCTION
AIR HEATER, STEAM LQES
TEMPERATURE
The temperature of the steam should not exceed the maximum oper-
ating temperature prescribed for the air heater.
PRESSURE
If the steam pressure is in excess of maximum operating pressure
prescribed for the air heater a reducing valve should be mounted.
REGULATION
In the case of air heaters connected in series (as viewed in the air
flow direction) and where the temperature of the entering air may be
sub zero, the first air heater should operate at full steam while the
second air heater is regulated (see Fig. 4, page 2). Regulation of the
first air heater will only increase the risk of the coils freezing up.
POSITIONING
The air heater is designed for horizontal air flow.
CONNECTIONS
The piping and trapping etc. should be installed in such a way that its
weight will not bear upon the coil, nor press against it through me-
chanical expansion.
ACCESSORIES
To facilitate the installation or replacement of traps, valves etc., the air
heater connections may be fitted with flanges.
Steam main
Return main
Flexible fitting
Fixing point
Gate valve
Shut-off valve
Control valve
Strainer
Vacuum breaker
Dirt pocket and valve
Petcock
Condensate trap
Non-return valve
Condensate pump
Steam
Condensate
Air
Direction of flow
Direction of air flow
Pitch (arrow indicates direction of flow)
To overhead return main
SYMBOLS
Fig. 1.
3154 EUES SYMBOL ÅNGLEDNING
3154 EUES SYMBOL KONDENSATLEDNING
3154 EUES SYMBOL KOMPENSATOR
3154 EUES SYMBOL FIXPUNKT
3154 EUES SYMBOL STOR AVSTÄNGNINGSVENTIL
3154 EUES SYMBOL REGLERVENTIL
3154 EUES SYMBOL SIL
3154 EUES SYMBOL VAKUUMVENTIL
3154 EUES SYMBOL AVÖUFTARE
3154 EUES SYMBOL BACKVENTIL
3154 EUES SYMBOL KONDENSATAVLEDARE
3154 EUES SYMBOL FLÖDESRIKTNING
3154 EUES SYMBOL LUFTRIKTNING
1:100
3154 EUES SYMBOL LEDNINGSLUTNING
3154 EUES SYMBOL TILL ÖVERLIGGANDE KONDENSATLEDNING
3154 EUES SYMBOL KONDENSATPUMP
3154 EUES SYMBOL SMUTSFICKA MED AVTAPPNINGSVENTIL
3154 EUES SYMBOL AVSTÄNGNINGSVENTIL
LQES Air heater, steam - Installation instruction
2
FläktGroup DC_9148GB 20180412_R0
Specifications are subject to alteration without notice
CONNECTING-UP
To ensure that the system functions properly, the air heater and trap-
ping, etc. should be installed as shown in Figs. 2–4.The steam main
should always be connected at the top of the air heater whereas
the return main should be at the bottom.
3154 EUES schema
öppet system
S
S
C
C
A
A
Min.500
1 : 100
Fig. 2. Open System
3154 EUES schema
slutet system
S
S
C
C
A
A
Min.500
1 : 100
Fig. 3. Closed System
3154 EUES schema
två seriekopplade
C
A
AA
Min.500
S
1 : 100
Fig. 4. Two air heaters connected in series on the air side, b = 2.
CONTROL AND PIPING
The piping should be pitched to ensure that the condensate build-up is
drained off, and not admitted into the coil.
The return main should be pitched downward from the air heater.
All the accessories which are part of the system must be designed for
steam or for condensate respectively. They should be sized for the
pressure, temperature and flow for the installation concerned, and
be connected according to the recommendations of the manufac-
turer.
STEAM AND RETURN MAINS
As a rule, steam mains should be sized for high vel oci ties.The steam
should be dry and preferably super heat ed. Humid steam leads to cor-
rosion in the piping and may damage the air heaters and accessories
through water hammer.
The steam main should be drained of condensate up-stream of the air
heater and accessories by means of a shunt valve. The take-off should
be mounted as near to the air heater as possible and be designed to
separate the steam from the condensate in the pipe.
If the return main is pitched higher than the condensate trap, the coil
will operate at a static overpressure resulting from the w.g. height ”h”
(see Fig. 5) and the pres sure drop (i.e. resistance) in the condensate
trap and/ or other accessories. Consequently this form of over head
return main should be avoided.
LQES Air heater, steam - Installation instruction
3
FläktGroup DC_9148GB 20180412_R0
Specifications are subject to alteration without notice
Control and piping (Contd.)
The steam and condensate pipes should be sized accord ing to the
recommended load and not according to the connection size of the air
heater.
STRAINER
A strainer should be installed ahead of the control valve and conden-
sate trap, to collect foreign matter such as scales and rust flakes. If
they are not removed, these impurities will prevent the various acces-
sories from work ing properly and may even cause a stoppage in the
throttling discs of the air heater – thus reducing the heating efficiency
and at the same time increasing the risk of freezing-up.
3154 EUES Tryckförhållanden
S
P1
P
2
C
hm
Fig. 5. Pressure conditions with overhead return line.
MEASUREMENT OUTLET
If possible, the system should be fitted with an outlet to permit meas-
urement of the pressure, flow and temperature, both ahead of and af-
ter the air heater.
FLEXIBLE FITTINGS
Flexible fittings should be provided in all piping connections so as to
absorb expansion and contraction strains. Rigid piping connections
can cause serious physical damage to the air heater coil.
FIXING POINTS
All fixing points should be as close to the air heater as possible, so
as to protect it from the weight of the pip ing, valves etc., and from the
expansion strain.
GATE VALVES
Gate valves should be mounted ahead of, and after, other accessories.
This will facilitate cleaning of the strainer and replacement of trapping,
valves, etc.
CONTROL VALVES
The control valve should be sized according to the manu facturer’s
recommendations and not according to the size of the air heater con-
nections.
An electric regulating motor should not be mounted under the valve,
as water leakage from the valve will cause damage. The control valve
should be mounted as close to the air heater as possible and should
be installed according to the manufacturer’s instructions.
hm < p1 – p2 kp/cm2
10,3
VACUUM BREAKER
If the supply of steam to the air heater is reduced or shut off, there
will be a vacuum in the air heater, with the result that it will wholly or
partly fill with conden sate. If the temperature of the outside air is so
low that the coil may freeze up, the water must be emptied and the
air heater filled with air instead. This is the function of the vacuum
breaker. In air heaters where there is no danger of freezing up, a vac-
uum breaker need not be used; the risk of corrosion will be reduced
accordingly.
DIRT TRAP AND DRAIN COCK
It is recommended that a dirt trap be installed before the condensate
trap. Thus it will not be necessary to clean the strainer so often.
PETCOCK
Air which has entered the system through the vacuum
breaker, and likewise non-condensible gases from the steam, must be
eliminated. This is done by means of the petcock, which should be in-
stalled ahead of the condensate trap.
CONDENSATE TRAP
Each air heater (or tube row) should be provided with a condensate
trap. A single condensate trap should not be connected to more than
one air heater, regardless of its operation. The condensate trap also
prevents a return flow of steam to the coil via the return line.
The condensate trap should be sized according to the amount of con-
densation when the air heater is cold. Its capacity in litres/h should be
three to five times the calculated steam flow in kg/h.
The trap may be of such a type that a separate strainer and venting
valve will not be required.
To ensure that the condensate is emptied completely, the trap should
be installed at least 500 mm below the pipe connection of the air
heater.
In the case of a thermostatic condensate trap, a cool ing length of pip-
ing is required between the air heater and the trap. If the air heaters
are connected in series (see Fig. 4) the maximal heat is produced by
the first air heater. Its condensate trap must therefore be selected with
this in mind.
IMPORTANT!
When starting up, check the strainers at regular
intervals.
LQES Air heater, steam - Installation instruction
4
FläktGroup DC_9148GB 20180412_R0
Specifications are subject to alteration without notice
Control and piping (Contd.)
NON-RETURN VALVE
To prevent water hammer from other units connected to the system,
the installation should be fitted with a non-return valve or a conden-
sate trap.
When two air heaters are installed, each of them must be provided
with a non-return valve, to prevent an overflow of steam.
CONDENSATE PUMP
If an overhead return main is installed, the pump should be located
before the rise; this reduces the risk of cavitation in the pump, and en-
sures that the condensate is emptied completely.
FREEZE GUARD THERMOSTAT
Steam air heaters supplied with outside air should be protected by
means of a freeze guard thermostat, to be selected and mounted
according to the manufacturer’s instructions. However, its sensing
element should be mounted so that it does not come in contact with
un heated air.
With capillary tube thermostats, the element should be located at the
bottom of the air heater coil, on the condensate side, and not over the
entire face area. If the thermostat is of the bulb type, it should likewise
be mounted in the lower part of the coil, and parallel with the finned
tubes.
If the thermostat is not temperature-compensated, its cubicle should
be mounted in a location where the temperature is higher than that
required to trip the circuit breaker. If the cubicle of a thermostat which
is not compensated, is mounted on the casing of an air heater, or a
duct upstream of the air heater, it should be insulated by means of a
wood-fibre board or the like.
BY-PASS
Replacement of the regulating valve or condensate trap will be facili-
tated if a by-pass is installed as shown in Fig. 6.
STARTING-UP
Open the steam valve until the entire air heater is warm, then start the
fan motor.If the temperature if the outside air is below 0 °C, there is
risk of the air heater coil freezing, see “vacum breaker”.
Fig. 6.
IMPORTANT!
When installing air heaters which use steam as a
heating medium, great care should be exercized
when opening air vents and gate valves. Failure to do
this may result in serious damage through water hammer or a
discharge of steam.
FläktGroup assumes no responsibility for the connection of air
heaters to the heating system, or for any damage which may
arise through faulty planning, installation or maintenance of such
system. Piping, valves, etc. should be sized according to pressure
drop and function and not according to the size of the air heater
coil connections.The pipes should be installed in such a way that
the air heater does not bear their weight or is not subjected to ex-
pansion and contraction strain from the heating system.
The guarantee does not cover airheaters which have been dam-
aged through water hammer or freezing.
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FläktGroup LQES Air heater, stream Installation guide

FläktGroup
Brand
FläktGroup
Model
LQES Air heater, stream
Type
Installation guide
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