Powrmatic NCA-G 100 Installation And Servicing Instructions Download Page 9

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I O

DO NOT

ROT

TE - HOLD

DIAL

WHEN SETTING POINTERS

40 60

FAN

Fig 3 Honeywell L4064N

Set Point Dial

Fan Circuit

Summer /
W i n t e r
Switch

Limit Reset

Jumper Location

Limit Circuit

Fan Circuit

7.2

Burner Maintenance

1. Refer to the Burner Supplement supplied with the heater.

Note: Any references therein to the gas controls assembly
should be ignored.

7.3

Heat Exchanger Cleaning

1. Disconnect the gas supply at the inlet to the gas controls

assembly.

2. Disconnect the electrical connections from the heater

electrical panel to the buner at the burner.

3. Remove the nuts securing the burner to the heat exchanger

and remove the burner.

4. Remove the fan/limit thermostat as described in 7.5.4

and then remove the inner panel of the heater to expose
the heat exchanger clean out panel. Remove the nuts
securing the panel and remove the panel.

5. Remove the nuts securing the heat exchanger baffles

retention strip and remove strip.Withdraw the baffles.

6. Brush through heat exchanger tubes and remove loose

material using a vacuum cleaner. Remove any loose material
from the base of the combustion chamber, working through
the burner port.

7. Reassemble all components in reverse order. Inspect all

gaskets and replace if necessary.

7.4

Fan Assembly

1. Remove the upper and lower side panels on one side of

the heater to gain access to the fan.

2. Inspect the fan blades to see that they are not damaged

and that there is no excessive build up of deposits that
could give rise to an imbalance. If necessary clean the
fan blades using a stiff brush and vacuum cleaner. If it
is required to remove the fan for cleaning refer to section
7.4.3

7.5

Replacement of Faulty Components

7.5.1. Burner Components

1. Refer to the burner supplement supplied with the heater.

7.5.2 Gas Controls Assembly

7.5.2.1 NCA-G 100, 150

7.5.2.1.1 Gas Valve Coil.

1. To fit a new valve operating coil remove the electrical

supply plug, release the securing nut on top of the valve
stemand remove the nut and washer. Lift of the faulty
coil and fit the new coil in reverse order.

7.5.2.1.2 Block Valve Assemby.

1. Remove the electrical supply plug,
2. Release the unions on the connections at each end of the

assemby and remove complete assembly. Fit new assembly
in reverse order ensuring the valve assembly is correctly
orientated for the direction of gas flow.

7.5.2.2 NCA-G 200, 300

7.5.2.2.1 Block Valve Assembly.

1. Release the union on the gas service valve
2. Remove the electrical connection from the valve assembly.
3. Release the socket head cap screws securing the connection

flanges to the main gas block valve and remove the block.
Fit new assembly in reverse order ensuring correct
orientated for the direction of gas flow.

7.5.3 Main Air Fan and Motor

Note:

On heaters supplied as specials with 3ph motors ensure

that the fan direction of rotation corresponds with the
direction of rotation arrow on the fan guard or case. If
necessary reverse the direction of rotation by interchanging
any two of the motor live leads at the terminal strip in the
electrical panel.
1. Disconnect the fan motor electrical leads from the heater

terminal strip (Refer to the Wiring Diagram supplied)

2. Remove the upper and lower side panels on one side of

the heater.

3. Remove the two set screws, one on each side of the fan

mounting flange, the secure the fan to the fan shroud.

4. Withdraw the fan from the slide rails.
5. Reassemble in reverse order.

7.5.4 Fan and Limit Thermostat (Honeywell L4064N )

1. Release the single screw securing the fan and limit

thermostat cover and remove cover by pulling forward.

2. Release wiring from clamp terminals by pushing a small

screwdriver into the clamp release holes adjacent to the
clamps.

3. Remove the 2 screws securing the thermostat to the heater

panel and withdraw thermostat.

4. Reassemble new unit in reverse order refering to the

heater wiring diagram to ensure correct wiring location.

Important:

As supplied by the Manufacturer this fan/limit

thermostat is fitted with a brass jumper between the bottom
fan terminal and the bottom limit terminal (situated in the
slot between the two terminals). This MUST be removed, by
using a pair of thin nose pliers, before the replacement
thermostat is installed.
5. Ensure that the fan and limit settings are as follows:-

Fan ON

50°C

Fan OFF

30°C

Limit

110°C

Connections to Powrmatic External Controls

8.1

Powrtrol

NCA-G

connect to

Powrtrol