Beckett ADC 24Vdc - Manual (Page 10)

10
Section: Drive Component Maintenance
Figure 8. – Pump and Valve Assemblies
SK9810
C. Valve Coil and Stem Replacement
To determine if the valve coil requires replacement perform
the following steps.
1. Remove the cord set from the valve.
2. Place the leads from an ohmmeter across the coil.
3. A 24Vdc volt coil should measure between 60 and
75 ohms.
4. If the meter indicates an open circuit, replace the coil.
To check pump operation perform the following.
1. Check the operating pressure by removing the copper
tubing from the nozzle line and installing a pressure
gauge in the line. With the motor running and the coil
energized, check the gauge. The pressure should read
100 psig unless otherwise stated.
2. To check the cutoff function, deadhead the pressure
gauge onto the copper connector tube attached to the
nozzle port. Run the burner for a short period of time.
Shut the burner off; the pressure should drop and hold.
To replace the coil and/or pump assembly perform the
following steps.
1. Before servicing, turn off and/or disconnect all power
to the burner.
2. Remove the copper tube assembly when replacing
the pump or when removing the coil and the tube
blocks the coil.
3. Using a fl at tip screwdriver, press the fl at tip into the
spring washer to prevent it from rotating.
4. Using a 10mm wrench or adjustable wrench, remove
the nut and spring washer.
5. Remove the coil by lifting it straight up.
6. Remove the two base plate screws, then the base
plate by lifting straight up.
7. Remove valve stem assembly by pulling straight up.
8. To install the new stem and coil assemblies, follow
the above steps in reverse order, tightening each
part as you go.
9. Restore power, start the burner and perform
the combustion test described previously in this
manual.
10mm Nut
Coil
Base Plate
Stem Assembly
Nozzle Port
Fitting
Cordset
Pump Assembly
Bleed Valve
Spring Washer