1 of 12 © 2003 A 268 - 10/03

- Application BrochureBoiler Control 268

A 26810/03

Features of the Boiler Control 268Please refer to Essay E 005: Control Functions and Benefits for a detailed description of these features.

ApplicationThe tekmar Boiler Control 268 can control the supply water temperature from up to 9 on / off stages based on outdoor temperature, control for Domestic Hot Water (DHW) generation, a setpoint requirement or optionally an external input signal (0 - 10 V (dc)). A large easy to read display provides current system temperatures and operating status. The control has outputs for a primary pump and either a combustion air damper or alarm. Based on the mode of operation selected, the control can operate different combinations of boiler stages and boiler pumps.

• Outdoor Reset• Characterized Heating Curve• Water Temperature Setback• Boost• Warm Weather Shut Down• Boiler Outdoor Reset• Boiler Differential (Automatic)• Boiler Minimum Supply• Boiler Post Purge• DHW Boiler Reset Override• DHW Condensing Boiler• DHW External Demand

• DHW Post Purge• DHW Priority• DHW Setback• PID Staging• Equal Run Time Rotation• Lo / Hi Fire Boiler Rotation• Fixed Lead• Fixed Last• Fire Delay• Boiler Mass• Setpoint Boiler Reset Override• Setpoint Priority

115 V (ac)

24 V (ac)

AlarmBoiler Control 268Nine Stage Boiler & Setpoint

Menu Item

© 2003 A 268 - 10/03 2 of 12

Co

nce

pt

Dra

win

gT

his

is o

nly

a co

ncep

t dra

win

g, n

ot a

n en

gine

ered

dra

win

g. It

is n

ot in

tend

ed to

de

scrib

e a

com

plet

e sy

stem

, no

r an

y pa

rtic

ular

sys

tem

. It

is u

p to

the

sys

tem

de

sign

er t

o de

term

ine

the

nece

ssar

y co

mpo

nent

s fo

r an

d co

nfig

urat

ion

of

the

part

icul

ar s

yste

m b

eing

des

igne

d, in

clud

ing

addi

tiona

l equ

ipm

ent,

isol

atio

n re

lays

(fo

r lo

ads

grea

ter

than

the

con

trol

’s s

peci

fied

outp

ut r

atin

gs),

and

any

sa

fety

dev

ices

whi

ch in

the

judg

emen

t of t

he d

esig

ner

are

appr

opria

te, i

n or

der

to p

rope

rly s

ize,

con

figur

e an

d de

sign

tha

t sy

stem

and

to

ensu

re c

ompl

ianc

e w

ith b

uild

ing

and

safe

ty c

ode

requ

irem

ents

.te

kmar

Con

trol

Sys

tem

s Lt

d., C

anad

a; te

kmar

Con

trol

Sys

tem

s, In

c., U

.S.A

.; w

ww

.tek

mar

con

tro

ls.c

om

Hea

d O

ffic

e: 5

100

Silv

er S

tar

Ro

ad, V

ern

on

, B.C

. Can

ada,

V1B

3K

4; (

250)

545

-774

9 F

ax (

250)

545

-065

0

- A

pp

licat

ion

Mec

han

ical

Sys

tem

Op

erat

ion

The

Boi

ler

Con

trol

268

pro

vide

s ou

tdoo

r re

set t

o a

spac

e he

atin

g sy

stem

. The

268

pro

vide

s st

agin

g an

d ro

tatio

n fo

r th

ree

two-

stag

e bo

ilers

. The

boi

lers

are

pip

ed p

aral

lel p

rimar

y-se

cond

ary

and

the

indi

vidu

al b

oile

r pu

mps

are

con

trol

led

by th

e 26

8 to

allo

w fo

r po

st p

urgi

ng o

f the

boi

lers

afte

r th

ey h

ave

shut

off.

The

268

has

an

alar

m c

onta

ct th

at c

lose

s du

ring

an

erro

r m

essa

ge.

A1

= A

larm

P1

= P

rim

ary

Sys

tem

Pum

pP

2...P

4 =

Boi

ler

Pum

pS

1 =

Boi

ler

Sup

ply

Sen

sor

071

S2

= O

utdo

or S

enso

r 07

0V

1 =

Bal

anci

ng o

r P

ress

ure

Byp

ass

Val

ve

A 2

68-1

10/0

3

P4

P3

P2Out

door

Sen

sor

(S2)

070

115

V (

ac)

24 V

(ac

)

Cla

ss II

Tran

sfor

mer

268 P1

∆P

V1

TT

T

Boi

ler

Sup

ply

Sen

sor

(S1)

071

Ala

rm (

A1)

3 of 12 © 2003 A 268 - 10/03

Co

nce

pt

Dra

win

gT

his

is o

nly

a co

ncep

t dra

win

g, n

ot a

n en

gine

ered

dra

win

g. It

is n

ot in

tend

ed to

de

scrib

e a

com

plet

e sy

stem

, no

r an

y pa

rtic

ular

sys

tem

. It

is u

p to

the

sys

tem

de

sign

er t

o de

term

ine

the

nece

ssar

y co

mpo

nent

s fo

r an

d co

nfig

urat

ion

of

the

part

icul

ar s

yste

m b

eing

des

igne

d, in

clud

ing

addi

tiona

l equ

ipm

ent,

isol

atio

n re

lays

(fo

r lo

ads

grea

ter

than

the

con

trol

’s s

peci

fied

outp

ut r

atin

gs),

and

any

sa

fety

dev

ices

whi

ch in

the

judg

emen

t of t

he d

esig

ner

are

appr

opria

te, i

n or

der

to p

rope

rly s

ize,

con

figur

e an

d de

sign

tha

t sy

stem

and

to

ensu

re c

ompl

ianc

e w

ith b

uild

ing

and

safe

ty c

ode

requ

irem

ents

.te

kmar

Con

trol

Sys

tem

s Lt

d., C

anad

a; te

kmar

Con

trol

Sys

tem

s, In

c., U

.S.A

.; w

ww

.tek

mar

con

tro

ls.c

om

Hea

d O

ffic

e: 5

100

Silv

er S

tar

Ro

ad, V

ern

on

, B.C

. Can

ada,

V1B

3K

4; (

250)

545

-774

9 F

ax (

250)

545

-065

0

- A

pp

licat

ion

Ele

ctri

cal

requ

ired

optio

nal

Ess

enti

al C

on

tro

l Set

tin

gs

MO

DE

= 4

DH

W M

OD

E =

OF

F

A 2

68-1

10/0

3

A1

= A

larm

P1

= P

rim

ary

Sys

tem

Pum

pP

2...P

4 =

Boi

ler

Pum

pS

1 =

Boi

ler

Sup

ply

Sen

sor

071

S2

= O

utdo

or S

enso

r 07

0

Boi

ler

#1Lo

Hi

Boi

ler

#2Lo

Hi

Boi

ler

#3Lo

Hi

C24

V (

ac)

R

N11

5 V

(ac

)

Cla

ss II

Tran

sfor

mer

L

S1 S

2

P1

P2

P3

P4

A1

Do

no

t ap

ply

po

wer

1 Com

2 Boil

Sup

3 Boil

Ret

4 Out

5 UnO Sw

6 Boil

Dem

7 Com

Dem

8Se

tp/

DH

W

9 Powe

rN

LPr

im P1

12 C.A

./Al

arm

DH

W

1314 R

elay

1

1510

11

1

16 Rel

ay2

17 2

18 Rel

ay3

19 3

20 Rel

ay4

21 4

22 Rel

ay5

23 5

24 Rel

ay6

25 6

26 Rel

ay7

27 7

28 Rel

ay8

29 8

30 Rel

ay 9

/

31

268

5A5A

5A5A

5A5A

5A5A

5A5A

5A

+-

© 2003 A 268 - 10/03 4 of 12

Co

nce

pt

Dra

win

gT

his

is o

nly

a co

ncep

t dra

win

g, n

ot a

n en

gine

ered

dra

win

g. It

is n

ot in

tend

ed to

de

scrib

e a

com

plet

e sy

stem

, no

r an

y pa

rtic

ular

sys

tem

. It

is u

p to

the

sys

tem

de

sign

er t

o de

term

ine

the

nece

ssar

y co

mpo

nent

s fo

r an

d co

nfig

urat

ion

of

the

part

icul

ar s

yste

m b

eing

des

igne

d, in

clud

ing

addi

tiona

l equ

ipm

ent,

isol

atio

n re

lays

(fo

r lo

ads

grea

ter

than

the

con

trol

’s s

peci

fied

outp

ut r

atin

gs),

and

any

sa

fety

dev

ices

whi

ch in

the

judg

emen

t of t

he d

esig

ner

are

appr

opria

te, i

n or

der

to p

rope

rly s

ize,

con

figur

e an

d de

sign

tha

t sy

stem

and

to

ensu

re c

ompl

ianc

e w

ith b

uild

ing

and

safe

ty c

ode

requ

irem

ents

.te

kmar

Con

trol

Sys

tem

s Lt

d., C

anad

a; te

kmar

Con

trol

Sys

tem

s, In

c., U

.S.A

.; w

ww

.tek

mar

con

tro

ls.c

om

Hea

d O

ffic

e: 5

100

Silv

er S

tar

Ro

ad, V

ern

on

, B.C

. Can

ada,

V1B

3K

4; (

250)

545

-774

9 F

ax (

250)

545

-065

0

- A

pp

licat

ion

Mec

han

ical

A 2

68-2

10/0

3

Sys

tem

Op

erat

ion

The

Boi

ler

Con

trol

268

pro

vide

s ou

tdoo

r re

set

to a

spa

ce h

eatin

g sy

stem

and

set

poin

t op

erat

ion

for

a sp

a. T

he 2

68

prov

ides

sta

ging

and

rot

atio

n fo

r th

ree

thre

e-st

age

boile

rs. T

he b

oile

rs a

re p

iped

in re

vers

e re

turn

with

a s

ingl

e pu

mp.

The

sp

a is

pip

ed in

prim

ary-

seco

ndar

y to

the

boile

rs. T

he s

pace

hea

ting

zone

s ar

e pi

ped

in p

rimar

y-se

cond

ary

to th

e bo

ilers

. T

he 2

68 h

as a

n al

arm

con

tact

that

clo

ses

durin

g an

err

or m

essa

ge.

Out

door

Sen

sor

(S2)

070

150

115

V (

ac)

24 V

(ac

)

Cla

ss II

Tran

sfor

mer

268

P3

R2

Z1

Z2

Z3

P1

∆P V3

R1

V2

P2

V1

MM

M

Boi

ler

Sup

ply

Sen

sor

(S1)

071

Spa

Sen

sor

(S3)

071

Ala

rm (

A1)

A1

= A

larm

P1

= P

rim

ary

Pum

pP

2 =

Spa

Pum

pP

3 =

Sys

tem

Pum

pR

1, R

2 =

Rel

ay 0

03S

1 =

Boi

ler

Sup

ply

Sen

sor

071

S2

= O

utdo

or S

enso

r 07

0S

3 =

Spa

Sen

sor

071

V1,

V2

= B

alan

cing

Val

ve o

r G

lob

e V

alve

V3

= P

ress

ure

Diff

eren

tial B

ypas

s V

alve

Z1,

...Z

3 =

Zon

e V

alve

5 of 12 © 2003 A 268 - 10/03

Co

nce

pt

Dra

win

gT

his

is o

nly

a co

ncep

t dra

win

g, n

ot a

n en

gine

ered

dra

win

g. It

is n

ot in

tend

ed to

de

scrib

e a

com

plet

e sy

stem

, no

r an

y pa

rtic

ular

sys

tem

. It

is u

p to

the

sys

tem

de

sign

er t

o de

term

ine

the

nece

ssar

y co

mpo

nent

s fo

r an

d co

nfig

urat

ion

of

the

part

icul

ar s

yste

m b

eing

des

igne

d, in

clud

ing

addi

tiona

l equ

ipm

ent,

isol

atio

n re

lays

(fo

r lo

ads

grea

ter

than

the

con

trol

’s s

peci

fied

outp

ut r

atin

gs),

and

any

sa

fety

dev

ices

whi

ch in

the

judg

emen

t of t

he d

esig

ner

are

appr

opria

te, i

n or

der

to p

rope

rly s

ize,

con

figur

e an

d de

sign

tha

t sy

stem

and

to

ensu

re c

ompl

ianc

e w

ith b

uild

ing

and

safe

ty c

ode

requ

irem

ents

.te

kmar

Con

trol

Sys

tem

s Lt

d., C

anad

a; te

kmar

Con

trol

Sys

tem

s, In

c., U

.S.A

.; w

ww

.tek

mar

con

tro

ls.c

om

Hea

d O

ffic

e: 5

100

Silv

er S

tar

Ro

ad, V

ern

on

, B.C

. Can

ada,

V1B

3K

4; (

250)

545

-774

9 F

ax (

250)

545

-065

0

- A

pp

licat

ion

Ele

ctri

cal

requ

ired

optio

nal

Ess

enti

al C

on

tro

l Set

tin

gs

MO

DE

= 5

Set

poin

t MO

DE

= 3

A 2

68-2

10/0

3

A1

= A

larm

P1

= P

rim

ary

Pum

pP

2 =

Spa

Pum

pP

3 =

Sys

tem

Pum

pR

1, R

2 =

Rel

ay 0

03S

1 =

Boi

ler

Sup

ply

Sen

sor

071

S2

= O

utdo

or S

enso

r 07

0S

3 =

Spa

Sen

sor

071

Z1,

...Z

3 =

Zon

e V

alve

S3

C24

V (

ac)

R

N11

5 V

(ac

)

Cla

ss II

Tran

sfor

mer

L

S1 S

2

P1

A1

P2

R1

R2

Z1.

..Z3

Do

no

t ap

ply

po

wer

1 Com

2 Boil

Sup

3 Boil

Ret

4 Out

5 UnO Sw

6 Boil

Dem

7 Com

Dem

8Se

tp/

DH

W

9 Powe

rN

LPr

im P1

12 C.A

./Al

arm

DH

W

1314 R

elay

1

1510

11

1

16 Rel

ay2

17 2

18 Rel

ay3

19 3

20 Rel

ay4

21 4

22 Rel

ay5

23 5

24 Rel

ay6

25 6

26 Rel

ay7

27 7

28 Rel

ay8

29 8

30 Rel

ay 9

/

31

268

5A5A

5A5A

5A5A

5A5A

5A5A

5A

+-

7 8 1 2

6 5 4 3

P3

7 8 1 2

6 5 4 3

Boi

ler

#1

LoM

edH

iB

oile

r #2

LoM

edH

i

Boi

ler

#3

LoM

edH

i

C-

8A8A

No

Pow

er

R+

Com

N/O

N/C

12

34

56

7

Sens

orPo

wer

150

OnPWM

Off

© 2003 A 268 - 10/03 6 of 12

Co

nce

pt

Dra

win

gT

his

is o

nly

a co

ncep

t dra

win

g, n

ot a

n en

gine

ered

dra

win

g. It

is n

ot in

tend

ed to

de

scrib

e a

com

plet

e sy

stem

, no

r an

y pa

rtic

ular

sys

tem

. It

is u

p to

the

sys

tem

de

sign

er t

o de

term

ine

the

nece

ssar

y co

mpo

nent

s fo

r an

d co

nfig

urat

ion

of

the

part

icul

ar s

yste

m b

eing

des

igne

d, in

clud

ing

addi

tiona

l equ

ipm

ent,

isol

atio

n re

lays

(fo

r lo

ads

grea

ter

than

the

con

trol

’s s

peci

fied

outp

ut r

atin

gs),

and

any

sa

fety

dev

ices

whi

ch in

the

judg

emen

t of t

he d

esig

ner

are

appr

opria

te, i

n or

der

to p

rope

rly s

ize,

con

figur

e an

d de

sign

tha

t sy

stem

and

to

ensu

re c

ompl

ianc

e w

ith b

uild

ing

and

safe

ty c

ode

requ

irem

ents

.te

kmar

Con

trol

Sys

tem

s Lt

d., C

anad

a; te

kmar

Con

trol

Sys

tem

s, In

c., U

.S.A

.; w

ww

.tek

mar

con

tro

ls.c

om

Hea

d O

ffic

e: 5

100

Silv

er S

tar

Ro

ad, V

ern

on

, B.C

. Can

ada,

V1B

3K

4; (

250)

545

-774

9 F

ax (

250)

545

-065

0

- A

pp

licat

ion

Mec

han

ical

A 2

68-3

10/0

3

Sys

tem

Op

erat

ion

The

Boi

ler

Con

trol

268

pro

vide

s D

HW

ope

ratio

n to

a s

ingl

e do

mes

tic h

ot w

ater

sto

rage

tank

. The

268

pro

vide

s st

agin

g,

rota

tion

and

purg

ing

to fo

ur tw

o-st

age

boile

rs. T

he b

oile

rs a

re p

iped

in r

ever

se r

etur

n w

ith a

sin

gle

pum

p. A

com

bust

ion

air

dam

per

is a

lso

cont

rolle

d by

the

268.

A1

= D

HW

Aqu

asta

tC

1 =

Com

bust

ion

Air

Dam

per

P1

= P

rim

ary

Sys

tem

Pum

pS

1 =

Boi

ler

Sup

ply

Sen

sor

071

S2

= O

utdo

or S

enso

r 07

0

MC

ombu

stio

nA

ir D

ampe

r (C

1)O

utdo

or S

enso

r(S

2) 0

70

115

V (

ac)

24 V

(ac

)

Cla

ss II

Tran

sfor

mer

P1

A1

268

Boi

ler

Sup

ply

Sen

sor

(S1)

071

7 of 12 © 2003 A 268 - 10/03

Co

nce

pt

Dra

win

gT

his

is o

nly

a co

ncep

t dra

win

g, n

ot a

n en

gine

ered

dra

win

g. It

is n

ot in

tend

ed to

de

scrib

e a

com

plet

e sy

stem

, no

r an

y pa

rtic

ular

sys

tem

. It

is u

p to

the

sys

tem

de

sign

er t

o de

term

ine

the

nece

ssar

y co

mpo

nent

s fo

r an

d co

nfig

urat

ion

of

the

part

icul

ar s

yste

m b

eing

des

igne

d, in

clud

ing

addi

tiona

l equ

ipm

ent,

isol

atio

n re

lays

(fo

r lo

ads

grea

ter

than

the

con

trol

’s s

peci

fied

outp

ut r

atin

gs),

and

any

sa

fety

dev

ices

whi

ch in

the

judg

emen

t of t

he d

esig

ner

are

appr

opria

te, i

n or

der

to p

rope

rly s

ize,

con

figur

e an

d de

sign

tha

t sy

stem

and

to

ensu

re c

ompl

ianc

e w

ith b

uild

ing

and

safe

ty c

ode

requ

irem

ents

.te

kmar

Con

trol

Sys

tem

s Lt

d., C

anad

a; te

kmar

Con

trol

Sys

tem

s, In

c., U

.S.A

.; w

ww

.tek

mar

con

tro

ls.c

om

Hea

d O

ffic

e: 5

100

Silv

er S

tar

Ro

ad, V

ern

on

, B.C

. Can

ada,

V1B

3K

4; (

250)

545

-774

9 F

ax (

250)

545

-065

0

- A

pp

licat

ion

Ele

ctri

cal

requ

ired

optio

nal

Ess

enti

al C

on

tro

l Set

tin

gs

MO

DE

= 3

DH

W M

OD

E =

1

A 2

68-3

10/0

3

A1

= D

HW

Aqu

asta

tC

1 =

Com

bust

ion

Air

Dam

per

P1

= P

rim

ary

Sys

tem

Pum

pS

1 =

Boi

ler

Sup

ply

Sen

sor

071

S2

= O

utdo

or S

enso

r 07

0

C24

V (

ac)

R

N11

5 V

(ac

)

Cla

ss II

Tran

sfor

mer

L

S1 S

2

P1

Do

no

t ap

ply

po

wer

1 Com

2 Boil

Sup

3 Boil

Ret

4 Out

5 UnO Sw

6 Boil

Dem

7 Com

Dem

8Se

tp/

DH

W

9 Powe

rN

LPr

im P1

12 C.A

./Al

arm

DH

W

1314 R

elay

1

1510

11

1

16 Rel

ay2

17 2

18 Rel

ay3

19 3

20 Rel

ay4

21 4

22 Rel

ay5

23 5

24 Rel

ay6

25 6

26 Rel

ay7

27 7

28 Rel

ay8

29 8

30 Rel

ay 9

/

31

268

5A5A

5A5A

5A5A

5A5A

5A5A

5A

+-

MC

1A

1

Boi

ler

#1Lo

Hi

Boi

ler

#3Lo

Hi

Boi

ler

#2Lo

Hi

Boi

ler

#4Lo

Hi

© 2003 A 268 - 10/03 8 of 12

Co

nce

pt

Dra

win

gT

his

is o

nly

a co

ncep

t dra

win

g, n

ot a

n en

gine

ered

dra

win

g. It

is n

ot in

tend

ed to

de

scrib

e a

com

plet

e sy

stem

, no

r an

y pa

rtic

ular

sys

tem

. It

is u

p to

the

sys

tem

de

sign

er t

o de

term

ine

the

nece

ssar

y co

mpo

nent

s fo

r an

d co

nfig

urat

ion

of

the

part

icul

ar s

yste

m b

eing

des

igne

d, in

clud

ing

addi

tiona

l equ

ipm

ent,

isol

atio

n re

lays

(fo

r lo

ads

grea

ter

than

the

con

trol

’s s

peci

fied

outp

ut r

atin

gs),

and

any

sa

fety

dev

ices

whi

ch in

the

judg

emen

t of t

he d

esig

ner

are

appr

opria

te, i

n or

der

to p

rope

rly s

ize,

con

figur

e an

d de

sign

tha

t sy

stem

and

to

ensu

re c

ompl

ianc

e w

ith b

uild

ing

and

safe

ty c

ode

requ

irem

ents

.te

kmar

Con

trol

Sys

tem

s Lt

d., C

anad

a; te

kmar

Con

trol

Sys

tem

s, In

c., U

.S.A

.; w

ww

.tek

mar

con

tro

ls.c

om

Hea

d O

ffic

e: 5

100

Silv

er S

tar

Ro

ad, V

ern

on

, B.C

. Can

ada,

V1B

3K

4; (

250)

545

-774

9 F

ax (

250)

545

-065

0

- A

pp

licat

ion

Mec

han

ical

A 2

68-4

10/0

3

A1

= D

HW

Aqu

asta

tC

1 =

Com

bust

ion

Air

Dam

per

P1

= P

rim

ary

Sys

tem

Pum

pP

2...P

5 =

Boi

ler

Pum

pP

6 =

DH

W P

ump

S1

= B

oile

r S

uppl

y S

enso

r 07

1S

2 =

Boi

ler

Ret

urn

Sen

sor

071

Sys

tem

Op

erat

ion

The

Boi

ler

Con

trol

268

acce

pts

a 0

- 10

V (

dc)

sign

al f

rom

an

Ene

rgy

Man

agem

ent

Sys

tem

to

supp

ly h

eat

to a

spa

ce

heat

ing

syst

em. T

he 2

68 o

pera

tes

an in

dire

ct d

omes

tic h

ot w

ater

tank

bas

ed u

pon

a de

man

d fro

m th

e ta

nk a

quas

tat.

The

26

8 pr

ovid

es s

tagi

ng a

nd ro

tatio

n fo

r up

to fo

ur s

ingl

e st

age

boile

rs. T

he b

oile

rs a

re p

iped

in p

aral

lel p

rimar

y-se

cond

ary

and

the

boile

r pu

mps

are

con

trolle

d by

the

268

to a

llow

for

post

pur

ging

of t

he b

oile

rs a

fter

they

hav

e sh

ut o

ff. A

com

bust

ion

air

dam

per

is a

lso

cont

rolle

d by

the

268.

P3

P4

P5

P2

MC

ombu

stio

nA

ir D

ampe

r (C

1)

268

P1

A1

P6

DH

WTa

nk

115

V (

ac)

Ana

log

Inpu

t fro

m E

MS

24 V

(ac

)

Cla

ss II

Tran

sfor

mer

Boi

ler

Sup

ply

Sen

sor

(S1)

071

Boi

ler

Ret

urn

Sen

sor

(S2)

071

9 of 12 © 2003 A 268 - 10/03

Co

nce

pt

Dra

win

gT

his

is o

nly

a co

ncep

t dra

win

g, n

ot a

n en

gine

ered

dra

win

g. It

is n

ot in

tend

ed to

de

scrib

e a

com

plet

e sy

stem

, no

r an

y pa

rtic

ular

sys

tem

. It

is u

p to

the

sys

tem

de

sign

er t

o de

term

ine

the

nece

ssar

y co

mpo

nent

s fo

r an

d co

nfig

urat

ion

of

the

part

icul

ar s

yste

m b

eing

des

igne

d, in

clud

ing

addi

tiona

l equ

ipm

ent,

isol

atio

n re

lays

(fo

r lo

ads

grea

ter

than

the

con

trol

’s s

peci

fied

outp

ut r

atin

gs),

and

any

sa

fety

dev

ices

whi

ch in

the

judg

emen

t of t

he d

esig

ner

are

appr

opria

te, i

n or

der

to p

rope

rly s

ize,

con

figur

e an

d de

sign

tha

t sy

stem

and

to

ensu

re c

ompl

ianc

e w

ith b

uild

ing

and

safe

ty c

ode

requ

irem

ents

.te

kmar

Con

trol

Sys

tem

s Lt

d., C

anad

a; te

kmar

Con

trol

Sys

tem

s, In

c., U

.S.A

.; w

ww

.tek

mar

con

tro

ls.c

om

Hea

d O

ffic

e: 5

100

Silv

er S

tar

Ro

ad, V

ern

on

, B.C

. Can

ada,

V1B

3K

4; (

250)

545

-774

9 F

ax (

250)

545

-065

0

- A

pp

licat

ion

Ele

ctri

cal

requ

ired

optio

nal

A 2

68-4

10/0

3

Ess

enti

al C

on

tro

l Set

tin

gs

MO

DE

= 2

DH

W M

OD

E =

1 (

no p

riorit

y)

2 (w

ith p

riorit

y)

A1

= D

HW

Aqu

asta

tC

1 =

Com

bust

ion

Air

Dam

per

P1

= P

rim

ary

Sys

tem

Pum

pP

2...P

5 =

Boi

ler

Pum

pP

6 =

DH

W P

ump

S1

= B

oile

r S

uppl

y S

enso

r 07

1S

2 =

Boi

ler

Ret

urn

Sen

sor

071

C24

V (

ac)

R

N11

5 V

(ac

)

Cla

ss II

Tran

sfor

mer

L

S1 S2

500Ω

0-20

mA

or 0

-10

V (

dc)

P4

P3

P2

P1

P5

P6

Do

no

t ap

ply

po

wer

1 Com

2 Boil

Sup

3 Boil

Ret

4 Out

5 UnO Sw

6 Boil

Dem

7 Com

Dem

8Se

tp/

DH

W

9 Powe

rN

LPr

im P1

12 C.A

./Al

arm

DH

W

1314 R

elay

1

1510

11

1

16 Rel

ay2

17 2

18 Rel

ay3

19 3

20 Rel

ay4

21 4

22 Rel

ay5

23 5

24 Rel

ay6

25 6

26 Rel

ay7

27 7

28 Rel

ay8

29 8

30 Rel

ay 9

/

31

268

5A5A

5A5A

5A5A

5A5A

5A5A

5A

+-

MC

1A

1

Boi

ler

#1B

oile

r#2

Boi

ler

#3B

oile

r#4

© 2003 A 268 - 10/03 10 of 12

Co

nce

pt

Dra

win

gT

his

is o

nly

a co

ncep

t dra

win

g, n

ot a

n en

gine

ered

dra

win

g. It

is n

ot in

tend

ed to

de

scrib

e a

com

plet

e sy

stem

, no

r an

y pa

rtic

ular

sys

tem

. It

is u

p to

the

sys

tem

de

sign

er t

o de

term

ine

the

nece

ssar

y co

mpo

nent

s fo

r an

d co

nfig

urat

ion

of

the

part

icul

ar s

yste

m b

eing

des

igne

d, in

clud

ing

addi

tiona

l equ

ipm

ent,

isol

atio

n re

lays

(fo

r lo

ads

grea

ter

than

the

con

trol

’s s

peci

fied

outp

ut r

atin

gs),

and

any

sa

fety

dev

ices

whi

ch in

the

judg

emen

t of t

he d

esig

ner

are

appr

opria

te, i

n or

der

to p

rope

rly s

ize,

con

figur

e an

d de

sign

tha

t sy

stem

and

to

ensu

re c

ompl

ianc

e w

ith b

uild

ing

and

safe

ty c

ode

requ

irem

ents

.te

kmar

Con

trol

Sys

tem

s Lt

d., C

anad

a; te

kmar

Con

trol

Sys

tem

s, In

c., U

.S.A

.; w

ww

.tek

mar

con

tro

ls.c

om

Hea

d O

ffic

e: 5

100

Silv

er S

tar

Ro

ad, V

ern

on

, B.C

. Can

ada,

V1B

3K

4; (

250)

545

-774

9 F

ax (

250)

545

-065

0

- A

pp

licat

ion

Mec

han

ical

A 2

68-5

10/0

3

A1

= D

HW

Aqu

asta

tA

2 =

Ala

rmP

1 =

Pri

mar

y P

ump

P2

= D

HW

Pum

pP

3 =

Sys

tem

Pum

pR

1, R

2 =

Rel

ay 0

03S

1 =

Boi

ler

Sup

ply

Sen

sor

071

S2

= O

utdo

or S

enso

r 07

0Z

1...Z

3 =

Zon

e V

alve

Sys

tem

Op

erat

ion

The

Boi

ler

Con

trol

268

pro

vide

s ou

tdoo

r re

set

to a

spa

ce h

eatin

g sy

stem

and

dom

estic

hot

wat

er o

pera

tion.

The

268

pr

ovid

es s

tagi

ng a

nd r

otat

ion

for

four

two-

stag

e bo

ilers

. The

boi

lers

are

pip

ed in

rev

erse

ret

urn

with

a s

ingl

e pu

mp.

The

sp

ace

heat

ing

zone

s ar

e pi

ped

in p

rimar

y-se

cond

ary

to t

he b

oile

rs.

The

dom

estic

hot

wat

er t

ank

is p

iped

in

prim

ary-

seco

ndar

y to

the

boi

lers

and

has

an

exte

rnal

rel

ay t

o pr

ovid

e pr

iorit

y ov

er t

he h

eatin

g sy

stem

. T

he 2

68 h

as a

n al

arm

co

ntac

t tha

t clo

ses

durin

g an

err

or m

essa

ge.

Out

door

Sen

sor

(S2)

070

115

V (

ac)

24 V

(ac

)

Cla

ss II

Tran

sfor

mer

P1

268

P3

P2

R2

R1

A1

Z1

Z2

Z3

DH

WTa

nk

tekm

ar 5

00 s

erie

s th

erm

osta

ts

MM

M

Boi

ler

Sup

ply

Sen

sor

(S1)

071

Ala

rm (

A2)

11 of 12 © 2003 A 268 - 10/03

Co

nce

pt

Dra

win

gT

his

is o

nly

a co

ncep

t dra

win

g, n

ot a

n en

gine

ered

dra

win

g. It

is n

ot in

tend

ed to

de

scrib

e a

com

plet

e sy

stem

, no

r an

y pa

rtic

ular

sys

tem

. It

is u

p to

the

sys

tem

de

sign

er t

o de

term

ine

the

nece

ssar

y co

mpo

nent

s fo

r an

d co

nfig

urat

ion

of

the

part

icul

ar s

yste

m b

eing

des

igne

d, in

clud

ing

addi

tiona

l equ

ipm

ent,

isol

atio

n re

lays

(fo

r lo

ads

grea

ter

than

the

con

trol

’s s

peci

fied

outp

ut r

atin

gs),

and

any

sa

fety

dev

ices

whi

ch in

the

judg

emen

t of t

he d

esig

ner

are

appr

opria

te, i

n or

der

to p

rope

rly s

ize,

con

figur

e an

d de

sign

tha

t sy

stem

and

to

ensu

re c

ompl

ianc

e w

ith b

uild

ing

and

safe

ty c

ode

requ

irem

ents

.te

kmar

Con

trol

Sys

tem

s Lt

d., C

anad

a; te

kmar

Con

trol

Sys

tem

s, In

c., U

.S.A

.; w

ww

.tek

mar

con

tro

ls.c

om

Hea

d O

ffic

e: 5

100

Silv

er S

tar

Ro

ad, V

ern

on

, B.C

. Can

ada,

V1B

3K

4; (

250)

545

-774

9 F

ax (

250)

545

-065

0

- A

pp

licat

ion

Ele

ctri

cal

requ

ired

optio

nal

Ess

enti

al C

on

tro

l Set

tin

gs

MO

DE

= 3

DH

W M

OD

E =

4 (

with

prio

rity)

A 2

68-5

10/0

3

A1

= D

HW

Aqu

asta

tA

2 =

Ala

rmP

1 =

Pri

mar

y P

ump

P2

= D

HW

Pum

pP

3 =

Sys

tem

Pum

pR

1, R

2 =

Rel

ay 0

03S

1 =

Boi

ler

Sup

ply

Sen

sor

071

S2

= O

utdo

or S

enso

r 07

0Z

1...Z

3 =

Zon

e V

alve

C24

V (

ac)

R

N11

5 V

(ac

)

Cla

ss II

Tran

sfor

mer

L

A1

R2

R1

P1

P2

P3

Z3

M

R

tekm

ar 5

00 S

erie

sTh

erm

osta

ts

CR

elay

1R

tekm

ar 5

00 S

erie

sTh

erm

osta

ts

CR

elay

1

Z2

M

R

tekm

ar 5

00 S

erie

sTh

erm

osta

ts

CR

elay

1

Z1

M

7 8 1 2

6 5 4 3

Do

no

t ap

ply

po

wer

1 Com

2 Boil

Sup

3 Boil

Ret

4 Out

5 UnO Sw

6 Boil

Dem

7 Com

Dem

8Se

tp/

DH

W

9 Powe

rN

LPr

im P1

12 C.A

./Al

arm

DH

W

1314 R

elay

1

1510

11

1

16 Rel

ay2

17 2

18 Rel

ay3

19 3

20 Rel

ay4

21 4

22 Rel

ay5

23 5

24 Rel

ay6

25 6

26 Rel

ay7

27 7

28 Rel

ay8

29 8

30 Rel

ay 9

/

31

268

5A5A

5A5A

5A5A

5A5A

5A5A

5A

+-

2 1 8 7

3 4 5 6

A2

S1 S

2

Boi

ler

#2Lo

Hi

Boi

ler

#1Lo

Hi

Boi

ler

#4Lo

Hi

Boi

ler

#3Lo

Hi

Product design, software and literature are Copyright © 2003 by:tekmar Control Systems Ltd. and tekmar Control Systems, Inc.

All specifications are subject to change without notice.Printed in Canada. A 268 - 10/03.

12 of 12

Specifi cations

tekmar Control Systems Ltd., Canadatekmar Control Systems, Inc., U.S.A.Head Office: 5100 Silver Star RoadVernon, B.C. Canada V1B 3K4(250) 545-7749 Fax. (250) 545-0650Web Site: www.tekmarcontrols.com

The following are the recommended specifications for the Boiler Control 268

• The control shall be able to operate up to a total of 9 on / off stages.

• The control shall be able to operate boilers that have one, two, three or four independent on / off stages.

• The control shall have the ability to calculate the boilers’ target temperature based on outdoor reset.

• The control shall have the ability to have the boilers’ target temperature set using an adjustable setpoint.

• The control shall have an adjustable warm weather shut down. The warm weather shut down only applies to outdoor reset operation.

• The control shall have a primary pump contact that operates during a call for space heating.

• The control shall have the ability to operate a domestic hot water contact that operates during a domestic hot water call.

• The control shall have the ability to limit the number of boilers operated during domestic hot water calls for heat.

• The control shall have the ability to display the current temperature difference between the return temperature and the supply temperature, ∆T.

• The control shall have an option to rotate the firing sequence of the boilers and the option for rotating the boiler firing sequence shall be based on the boilers’ accumulated running hours.

• The control shall use proportional, integral and derivative (PID) logic when staging boiler stages.

• The control shall have an adjustable Minimum Supply water temperature setting to help prevent condensation of flue gases and subsequent corrosion and blockage of the boilers’ heat exchanger and chimney.

• The control shall have the option of an automatic differential calculation in order to prevent short cycling of the stages.

• The control shall have the ability to operate a primary pump plus individual boiler pumps based on the mode of operation selected.

• The boiler pumps shall have an adjustable post purge setting that allows the pump to run for a set period of time after the boiler has been shut off.

• The control shall have the option of staging multistage boilers in either a Low – High sequence or a Low – Low sequence.

• The control shall have the option for a fixed lead rotation and when this option is selected, the control shall have an option for either a first on / first off, or first on / last off firing sequence.

• The control shall have the option for a fixed last rotation.

• The control shall have the option for either an alarm output or a combustion air damper output. If the combustion air damper output is selected, the control shall have an adjustable combustion air damper opening time.

• The control shall have an adjustable minimum inter-stage delay that can be set manually or calculated automatically by the control.

• The control shall have the option of accepting a 0 – 10 V (dc) input signal from an energy management system.

• When operating with a 0 – 10 V (dc) signal, the control shall have an adjustable offset setting as well as an adjustable input range.

• The control shall have two separate lockable access levels to limit the number of adjustments available to various users.

• The control shall have a test button that activates a pre-programmed test sequence testing all the control’s outputs.

• The control shall show a number of current sensor temperatures depending on the access level that has been selected.

• The control shall continually monitor its temperature sensors and provide an error message upon a control or sensor failure.

• The control shall record and display the running hours of each boiler.

• During extended periods of inactivity, the pumps that are operated by the control shall be periodically exercised to prevent seizure during long idle periods.