clean burn 525 oil pressure fluctuates

[vinnies auto]

Hi I have a cleanburn 175 with a CB 525 gun. Installed it in 09 and ran trouble free for the first 5 years.  Now   the unit will run forever but the oil pressure creeps downward with time.    setting it back at 2 psi  i find that when the unit reaches temp then restarts later the pressure is too high.  the longer its off the higher it may be. 5 psi will make the unit sputter and smoke and go on safety . but pressure is steady.  lowering it to 2 psi gets it running fine, but after a several hours  pressure goes as low a a half pound.       set it a 2 psi and we are good as long as the unit never cycles.  This is an on going problem and  I have changed the regulator, Nozzle. cleaned the heater block and all filters.  Pump  maintains 25 psi at all times.  With an open bleeder there is a full flow of oil without a bubble  any Ideas would be helpful

[ShopSpecialties]

Ok just to be clear you have a CB-1750 with a J-pump ? We have a couple of things I would look at first. #1 would be a burner rebuild. I am very picky about this and do not like my customers attempting it since they usually get frustrated and quit early before getting the inside of the block and nozzle holder spotless. #2 pump to pickup screen. There is a screen inside the pump head that should be cleaned every 2 years or so. Replace the pump cover gasket and do not use any kind of sealant. When oil pressure is dropping down how much vacuum are you pulling at the Lenz filter ? I have seen only a couple of times a rag or a big glob of something slowly plug the pickup screen, vacuum goes up on long run times causing oil pressure to drop. When the heater would shut off the rag/glob would fall off the screen.

[vinnies auto]

First thing  is a Thank You for trying to help.    Yes its a 1750 with a J pump.   I've cleaned the block, every plug removed and soaked and scrubbed until spotless.  all three filter screens cleaned.    installed a pressure gauge  on j pump pressure line and its always 25 lbs,  vacuum is close to zero at lenz filter.    there are 2  oil tanks plumbed together  and same exact reading  on either tank.   the unit ran last night no problem and pressure stayed just under 2psi. being it was 20 degreesout  it never stayed off for long.  when it sits and cools down for a few hours, it will start and light instantly, but pressure rises to about 5psi.  this makes the  flame sputter and  usually caused a lock out. with consistant  pressure and vacuum at J pump i cant imagine what can make pressure so erratic.  new oil regulator also. What is involved in a burner rebuild?

[ShopSpecialties]

When I do a burner rebuild I totally tear it down and scrub out each passage until spotless. Regulator and solenoid bodies cleaned spotless. Nozzle holder scrubbed out. On some preheat blocks I have had to clean up passages with a drill bit. The oil solenoid has some small passages on both the body and block that need to be checked closely. Every burner rebuild gets a service kit installed.

Sounds like things are good from pump to tank so that leaves the burner. What is your preheat block temp set at ?

[vinnies auto]

 Im quite sure all is well with plumbing as it worked perfectly for 5 winters.   The temp is at 140,  but ive raised it up and no changes.   i always kill the power to unit if its not being used, as i was told this keeps the block from plugging up.  Doesnt  quite add up how pressure at the gun varies so much.   seem like the longer the unit is off, the higher the pressure on start up.  once it settles to  about 2psi all is well.   I guess a rebuild and re clean all passages again is a good starting point
P.S.   one thing i did notice today.  units been running pretty much non stop, oil pressure holding steady at 2.  If i quickly raise air pressure to 20 psi   the oil pressure rises to 2.5 ,   if i lower the air to 10psi the oil drops a little too.  is there a connection between the two?

[ShopSpecialties]

I just did one a month ago with the same exact issue and after burner rebuild it is all good.

Another thing to possibly think about is have there been any changes to your oil storage ? Is the oil cold, room temp, etc ? With the oil in block being being 140* it will flow easy and the longer the heater is not running the colder the oil is in the tank. Hot oil flows easy and flame grows while cold oil flows slower and flame shortens. The more the heater runs the more consistent the oil temp is and the oil pressure stays steady. The heater only burns a hair over 1 gallon per hour so it will take a significant amount of run time to empty the block.   

[vinnies auto]

i have 2 tank, one outside, and one buried ,   switching them really makes no difference to the problem.  the buried one has slightly more vacuum on the lenz gauge. 

[ShopSpecialties]

Im quite sure all is well with plumbing as it worked perfectly for 5 winters.   The temp is at 140,  but ive raised it up and no changes.   i always kill the power to unit if its not being used, as i was told this keeps the block from plugging up.  Doesnt  quite add up how pressure at the gun varies so much.   seem like the longer the unit is off, the higher the pressure on start up.  once it settles to  about 2psi all is well.   I guess a rebuild and re clean all passages again is a good starting point
P.S.   one thing i did notice today.  units been running pretty much non stop, oil pressure holding steady at 2.  If i quickly raise air pressure to 20 psi   the oil pressure rises to 2.5 ,   if i lower the air to 10psi the oil drops a little too.  is there a connection between the two?

I just noticed your PS. Oil pressure should not change when adjusting the air. Bad o-ring on the nozzle ? Has the nozzle ever been changed ? Also make sure the nozzle t-stat is functioning properly. I have had them fail closed then the nozzle heating element stays on constantly baking the nozzle o-ring.

[ShopSpecialties]

Any updates ?

[vinnies auto]

I double checked the temp setting, even though its set at 140, it was more like  120.  I  raised it up so the block is actually 140.    the pressure is still  high on cold start up, But its been pretty cold here so it doesn't stay off for long.    i've been trying to watch it when it restarts and pressure still hits 3.5 psi  when it light up.  flame flickers a few times but keeps running.   takes a minute or 2 and pressure settles at 2psi.     seems a little better  but still not right.  i'll do the rebuild when we get a little warmer weather

[ShopSpecialties]

If you have no problems with ignition leave the preheat block temp at 140* on the t-stat. Higher temps will just bake the oil faster and make o-rings hard.

[vinnies auto]

   I found it locked out the other morning, unit was cool so it had been off for hours.    block was actually 140 , and unit lit up instantly,    and pressure shot to 6 psi.  within a few seconds flame sputters but pressure is stable.  if you can lower pressure fast enough it will keep running all day.    i lowered temp back to where it was. i'm still confused LOL