FläktGroup LQES Air heater, stream Installation guide

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 LUFT

3154 EUES SYMBOL AVÖUFTARE

3154 EUES SYMBOL KONDENSAT

3154 EUES SYMBOL ÅNGA

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

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



Min.500

1 : 100

Fig. 2. Open System

3154 EUES schema

slutet system



Min.500

1 : 100

Fig. 3. Closed System

3154 EUES schema

två seriekopplade



Min.500

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

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

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

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.

FläktGroup LQES Air heater, stream Installation guide

FläktGroup LQES Air heater, stream Installation guide

FläktGroup LQES Air heater, stream Installation guide

Related papers

Other documents