37
FAN
The driven variable pitch pulley drive and fixed fan
pulley are factory pre set and are suitable for most
applications.
The fan speed can be adjusted on the variable speed
pulley to allow for variations in duct resistances
inclusion of filters etc.
If will be necessary to check that the temperature rise
across the heater is within the tolerance shown in the
technical data.
On types 4-5-6 Three Phase heaters, fan rotation
should be checked prior to first ignition of the unit. It
may be necessary to adjust the motor pulley to achieve
correct motor running current as motor plate.
To check electrical absorption of the motor proceed
as follows:
•
Insert the ammeter on a phase of the general supply
line
•
Set the appliance to summer ventilation, so as to
exclude all other equipment (burner and auxiliary
parts)
Read the absorption figure on the ammeter and
compare it with the plate data for the motor shown in
the TECHNICAL DATA chapter.
Regulation of the variable pulley on the motor
1. Slacken the belt tension by unscrewing
screw
(5)
2.
Remove the belt (1)
3. Loosen grub screw (3) of the mobile part of
pulley with a hexagonal spanner (2)
4. Rotate the mobile part of the pulley so as to
obtain the pitch line diameter required
5. Lock the grub screw (3) tightly at the hub
hollow
6.
Mount and tighten the belt (1)
CONTROL
To ensure that the heater is working correctly certain
criteria need to be checked . Start up heater and check
the following
•
Check that the fan starts approximately 30 seconds
after ignition of the burner.
When the heater is at its full efficiency after about 20
minutes the following checks should be made:
•
Check that the horizontal fins are correctly set so as
to give the optimum heating performance and the air
flow is sufficient to cool the heat exchanger. ensure
where vertical fins are installed they are also open
and not restricting the air flow.
•
Check that there are no gas leaks
•
Check that the gas rate is correct using a meter.
•
Check injector pressure is correct.
•
Check temperature rise is correct to data plate.
•
Check the operation of the control and limit
thermostats TR, SND, LM.
•
Check that the room thermostat operates the burner
not the fan.
•
Check that the motor absorption is not more than
stated on data plate.
•
Check that the relays (type 4 - 5 - 6- and type 2 - 3
up rated fan) correspond to the value on the data
plate
•
Check that the flue venter and axial fan are working
correctly.
•
Check that the fan runs on 3–4 minutes after the
burner has shut down.
•
Check output corresponds to that on the data plate.
•
Check that the air flow corresponds to that shown in
the data plate and the duct calculations are correct.
•
Check that the temperature rise across the heater is
as per the data plate
•
Check that there is no condensate in the flue
gasses.
