JUMO STM-RW-2, STM-RW-2/OS Operating Instructions Manual

Flue gas Thermostat

Type STM-RW-2

B 60.1540.0

Operating Instructions

10.03/00329536

Please read these Operating Instructions before commissioning the instrument. Keep the
manual in a place that is accessible to all users at all times. Please assist us to improve
these operating instructions, where necessary. Your suggestions will be appreciated.

Phone
Fax

661 6003-0

+49

661 6003-607

+49

All necessary settings, and where appropriate, alterations inside the instrument are
described in these operating instructions. However, if any difficulties should still arise dur­ing commissioning, you are asked not to carry out any unauthorized manipulations on the
unit. You could endanger your rights under the instrument warranty! Please contact the
nearest subsidiary or the head office in such a case.

Contents

1 Introduction 4

1.1 Typographical conventions

1.1.1 Warning signs ................................................................................................. 4

1.1.2 Note signs ...................................................................................................... 4

1.2 Application

....................................................................................................

.........................................................................

2 Instrument identification 6

2.1 Nameplate

2.2 Type designation

.....................................................................................................

..........................................................................................

3 Mounting 7

3.1 Dimensions

3.2 Mounting the flue gas thermostat

3.3 Opening / closing the housing

3.4 Setpoint adjustment

...................................................................................................

..............................................................

....................................................................

.....................................................................................

4

5

6
6

7
8
9
9

4 Installation 10

4.1 Regulations and notes

4.2 Electrical connection

...............................................................................

.................................................................................

10
10

5 Instrument description 11

5.1 Technical data

5.2 Maintenance/fault

.............................................................................................

......................................................................................

11
11

1 Introduction

1.1 Typographical conventions

1.1.1 Warning signs

V

Danger

This sign is used when there may be
are ignored or not followed correctly!

Caution

A

1.1.2 Note signs

H
v

1

abc

This sign is used when there may be
are ignored or not followed correctly!

Note

This sign is used when your

Reference

This sign refers to

Footnote

special attention

further information

danger to personnel

damage to equipment

is drawn to a remark.

in other chapters or sections.

if the instructions

if the instructions

✱

Footnotes are remarks that
consist of two parts:

Marking in the text and the footnote text.
The marking in the text is arranged as continuous superscript numbers.
The footnote text (in smaller typeface) is placed at the bottom of the page and

starts with a superscript number.

Action

This sign indicates that
The individual steps are marked by this asterisk, e. g.

Open housing

✱

refer to specific points

an action to be performed

in the text. Footnotes

is described.

4

1.2 Application

The flue gas thermostat is used for monitoring flue gas temperatures on solid­fuel boilers in dual operation with oil-heated boilers.

Caution

A

When burning solid fuels, it is necessary to ensure that they are approved in
accordance with the corresponding local regulations on emission protection. If
this is ignored, corrosive gases may destroy the thermostat!

1 Introduction

Operation

The flue gas thermostat operates on the principle of rod expansion. The
immersion tube and the metal rod inside it have different expansion coeffi­cients, producing a temperature-dependent difference in length which acts on
the microswitch through a mechanism. The microswitch is operated above a
set temperature limit. After the immersion tube has cooled down by approx. 10
to 30 °C, the microswitch is reset. Should the immersion tube break, the circuit
is opened permanently.

5

2 Instrument identification

2.1 Nameplate

Fig. 1 Nameplate

Identify the instrument type by the nameplate and the type designation

✱

2.2 Type designation

STM-RW -2
STM rod thermostat with microswitch

-RW flue gas temperature monitor (ATW) with changeover

-2 with internal scale

STM-RW -2 /OS

/OS as STM-RW-2, but microswitch with 2 separate circuits

Basic type

contact

Extra code

1 x break contact (n.c.)
1 x make contact (n.o.)

6

e

The installation must be run down before mounting the flue gas thermostat

A

H

Type STM-RW-2 !

The mounting site should be easily accessible and as far as possible free from
shock and vibration.
The permissible ambient temperature must be observed (note possible radiant
heat).

3.1 Dimensions

3 Mounting

Fig. 2 Type STM-RW-2

7

3 Mounting

3.2 Mounting the flue gas thermostat

A

The thermostat is installed
The temperature probe must be at right angles to the flow direction and must
be exposed to the flue gas for its entire active length. The probe end must
have a clearance of at least 10 mm in the axial direction.

h

Secure the flue gas thermostat by its G 1/2 pipe thread.

without

a pocket.

Fig. 3 Installation of temperature probe

8

3.3 Opening/closing the housing

3 Mounting

Opening/closing
the cover

Unscrew housing screws ( 1 )

✱

Remove cover ( 2 ).

✱

(1)

(1)

Fig. 4 Opening/closing the housing cover
(1) Housing screws

(2) Cover

(1)

(1)

(2)

3.4 Setpoint adjustment

Open housing cover, see above

✱

Adjust setpoint on the spindle ( 1 ) using a screwdriver.

✱

Fig. 5 Setpoint adjustment
( 1 ) Spindle

(1)

9

4 Installation

4.1 Regulations and notes

The electrical connection must only be carried out by properly qualified per-

❏

sonnel.
The choice of cable, the installation and the electrical connection must con-

❏

form to the requirements of VDE 0100 “Regulations on the Installation of
Power Circuits with nominal voltages below 1000 V” or the appropriate
local regulations.

If contact with live parts is possible while working on the unit, it must be

❏

completely disconnected from the supply.
Earth the instrument at the PE terminal with the protective earth conductor.

❏

This cable must have at least the same cross-section as used for the supply
cables. Earth cables must be wired in a star configuration to a common
earth point that is connected to the protective earth of the supply. Do not
loop earth cables, i.e. do not run them from one instrument to another.

4.2 Electrical connection

Make connection according to the connection diagram

✱

10

Fig. 6 Type STM-RW-2

Fig. 7 Type STM-RW-2/OS

5.1 Technical data

5 Instrument description

Limit range

Permissible
ambient
temperature

Contact rating

Switching
differential

Switching point
accuracy
referred to
switch-off point

Mean ambient
temperature
error

standard:
special version:

at probe: max. +700°C
at thermostat head: max. +80°C, min. -50°C

10(2) A, 230 V AC, p.f. = 1(0.6)

0.25 A, 230 V DC

Limit range STM-RW-2 STM-RW-2/OS
+40°C to +120°C 10 to 18°C 10 to 30°C
+20°C to +400°C 10 to 22°C 10 to 40°C

Limit range Scale start Scale end

+40°C to +120°C

+20°C to +400°C + 0°C

switching point displacement,
referred to the deviation from +22°C ~ 0.07 °C/°C

+40°C to +120°C (factory-set to +100°C)

+20°C to +400°C (factory-set to +120°C)

+ 0°C

–10°C

–15°C

+ 0°C
–10°C

+ 0°C
–20°C

Protection

Fusing
required

Operating
medium

Time constant

Operating
position

Action

IP54 to EN 60 529, operation under normal conditions

16 A

flue gas

45 sec

≤

to DIN 16 257, NL0 — NL90 (other NL on request)

to EN 60730-1
Type 2BL= automatic action with micro switch-off in operation,

no auxiliary energy supply required.

5.2 Maintenance/fault

The flue gas thermostat requires no maintenance. In the event of a fault,
please contact your supplier or the head office (see back cover for address).

11

JUMO GmbH & Co. KG

Street address:
Moltkestraße 13 - 31
36039 Fulda, Germany
Delivery address:
Mackenrodtstraße 14
36039 Fulda, Germany
Postal address:
36035 Fulda, Germany
Phone: [phone]
Fax: [phone]
e-mail: [e-mail]
Internet: www.jumo.net

JUMO Instrument Co. Ltd.

JUMO House
Temple Bank, Riverway
Harlow, Essex CM20 2TT, UK
Phone: [phone]
Fax: [phone]
e-mail: [e-mail]
Internet: www.jumo.co.uk

JUMO PROCESS CONTROL INC.

885 Fox Chase, Suite 103
Coatesville, PA 19320, USA
Phone: [phone]

1-800-554-JUMO
Fax: [phone]
e-mail:
Internet: www.JumoUSA.com

[e-mail]