ELTRA ONH-2000 - Page 99

 2002 by ELTRA GmbH Germany – January 2002 – Service Manual OH 900 / ON 900 / ONH 2000
3.17-2
Requirement: the furnace has not to be moved in case of a power failure.
By adding a solenoid valve ( 8 ) and connecting the coil directly to 220 V AC, the piston
won´t change position in case of a power failure. If the piston was down, it will remain
down; if it was up, it will remain up in case of a power failure.
Both safety features can be combined, by means of the above upgrade circuit
3
4
2
+24V
red
0V
1
11380
11440
6
5
9
7
11492
12
11
10
0.2bar-3psi
original cable
The O ring
remains connected
blue
F
I
L
T
E
R
8
11390
2
2
0
V
A
C
3-16-1
3
4
2
F
I
L
T
E
R
2
2
0
V
A
C
1
11390
11380
6
5
7
8
3-16-3