Installation, use and maintenance guide
PIDRA 18
Page
14
ENG
5.2 GUIDELINES FOR PLANTS WITH ZONE VALVES
Note: above 61°C, the generator pump is always active as it is essential to dissipate the heat; therefore the solenoid valve
must be open for the following reasons:
• to prevent the generator from continually starting up and shutting off caused by the inevitable loss of heat to the header
and/or due to system tubing.
• to prevent the generator from raising the water temperature by just a few degrees each time it is switched off then back
on until it shuts down due to exceeding the maximum threshold temperature.
To adjust the ambient temperature in which the valve opened, we recommend connecting the room temperature
thermostat to the MODEM terminal (see dedicated paragraph) that allows the machine to be shut off via an external
contact and therefore also restarted.
This ensures that the generator only activates if there is a real request for heat from the zone in which the
chronothermostat is installed.
Several parallel-connected room temperature thermostats can be installed in the MODEM. This will ensure that the zone
requesting heat (contact closed) automatically activates the generator.
In the event of frequent startups and shut offs due to the heat produced by the generator not being absorbed, the manual
reset safety thermostat trips and blocks the generator.
N.B. Use chronothermostats having at least 2°C hysterisis.
Legenda
Key
Elettrovalvola sempre aperta
(zona con più assorbimento)
Solenoid valve always open
(zone with the most absorption)
COLLETTORE ANDATA
DELIVERY HEADER
COLLETTORE RITORNO
RETURN HEADER
A: andata impianto riscaldamento
A: heating system delivery
R: ritorno impianto riscaldamento
R: heating system return
S: saracinesca
S: gate valve
TA: elettrovalvola
TA: solenoid valve
VNR: valvola di non ritorno
VNR: nonreturn valve
VEC: vaso di espansione chiuso per protezione
impianto
VEC: closed expansion tank for system protection
VM3VT: valvola miscelatrice termostatca 55°C
VM3VT: thermostatic mixing valve 55°C
APPARECCHIO
APPLIANCE
VEC
TA
TA
El e t t r o v a l v o l a s e m p r e a p e r t a
( z o n a c o n p i u ' a s s o r b i m e n t o )
COLLETTORE ANDATA
COLLETTORE RITORNO
TA
S
S
VM3 VT
A
R
A : andata impianto riscaldamento
R : ritorno impianto riscaldamento
S : saracinesca
VNR : valvola di non ritorno
VEC : vaso di espansione chiuso per protezione impianto
VM3VT : valvola miscelatrice termostatica 55°c.
TA : elettrovalvola
VN R
A
PP
A
RE
C
C
HI
O
schema idraulico - valvole di zona.dft 03/05/2016
