Williamson-Thermoflo PMP-112, Manual

PMP-112 Multiposition 

Oil Furnaces

 – 

Furnace Manual

14

11/13 

3.1

CLEANING THE HEAT EXCHANGER 

It is not generally necessary to clean the heat exchanger or flue pipe 
every year, but it is advisable to have the oil burner service 
technician check the unit before each heating season to determine 
whether the cleaning or replacement of parts is necessary. 
If a cleaning is necessary, the following steps should be performed: 

1. 

Turn OFF all utilities upstream from the furnace; 

2. 

Disconnect the flue pipe; 

3. 

Remove the flue collar panel located at the front of the furnace; 

4. 

Remove the heat exchanger baffles; 

5. 

Disconnect the oil line and remove the oil burner; 

6.  Clean the secondary tubes and the primary cylinder with a stiff 

brush and a vacuum cleaner; 

7.  Before re-assembling the unit, the heat exchanger and 

combustion chamber should be inspected to determine if 
replacement is required; 

8.  After the cleaning replace the heat exchanger baffles, flue 

collar plate and oil burner; 

9. 

Readjust the burner for proper operation. 

3.2

CLEANING THE BLOCKED VENT SHUT-OFF 
DEVICE (BVSO) (IF INSTALLED) 

For continuous safe operation, the Blocked Vent Shut-off device 
(BVSO) must be inspected and maintained annually by a qualified 
service technician. 

1. 

Disconnect power to the appliance; 

2.  Remove the two screws holding on the BVSO assembly cover 

and remove the cover; 

3.  Remove the two screws holding the control box to the heat 

transfer tube assembly. Sliding the control box in the 
appropriate direction will unlock it from the heat transfer tube 
assembly; 

4. 

Carefully remove any build-up from the thermal switch surface; 

Do not dent or scratch the surface of the thermal 
switch. If the thermal switch is damaged it MUST 
be replaced. 

5.  Clean and remove any build-up or obstruction inside the heat 

transfer tube; 

6.  Re-mount, lock and fasten the control box with the 2 screws 

removed in step 4; 

7.  Re-attach the assembly cover with the screws removed in step 

2; 

8. 

Re-establish power to the unit. 

3.3

CLEANING OF THE BURNER HEAD 

Once annually, remove the retention head and electrodes from the 
drawer assembly and remove all foreign matter, if necessary. Also 
clean the extremity of the burner tube, if necessary. 

3.4

CHANGING THE NOZZLE 

Change the nozzle once a year with the one specified in Table 11. 

3.5

CHANGING THE OIL FILTER 

Tank Filter 

The tank filter should be changed as required. Follow the 
manufacturer’s instructions. 

Secondary Filter 

The 10 micron, or finer, filter cartridge should be changed annually. 
Follow the manufacturer’s instructions. 

3.6

CHANGING THE AIR FILTER 

Dirty filters have an impact on the efficiency of the furnace and 
increase fuel consumption. Air filters should be changed at least 
once a year. Very dusty conditions, the presence of animal hair and 
the like will require more frequent changing or cleaning.