Strangest pump problem ever

Unknown

Bumping this up.

Has anyone else ever run into this and been able to figure out what the problem was?

- Norm

Unknown

Here is the situation:

A unit heater suspended from a ceiling approx 12 feet above the floor. This unit has a Suntec-B pump with 1/2" supply and return lines. No heat.

My troubleshooting steps;

1. Point the jet line into a bucket and observe oil spraying from the jet line before a brief cavitation type noise is heard, and fuel stops spraying from the nozzle line.

2. Prime pump through the prime port and observe good flow with no air. Repeat step #1 with the same results.

3. I hook up 1/2" flexible oil lines into my 5 gallon oil can and repeat step #1. Same results. I observe good flow from the return line.

The pump is pumping oil, yet nothing is going to the nozzle port. Except briefly on start-up.

4. Replace the pumb with a new Suntec-B pump. Repeat step #3. Same results.

This iw where I sit on a 5 gallon pail and think for awhile.

%. Just for fun I remove the return line and bypass plug, and plug the return port. Prime the pump through the prime port and fire the unit. With this one pipe set-up I have continuous pressure to the nozzleport and the unit runs fine.

5. I hook up the old supply line and observe proper operation.

And this is the point where I scratch my head in wonder.

Heres my thinking;

The old pump must still be good if I am having the same problem with the new one.

The existing return line cannot be the problem because the problem existed with my flexible line in the 5 gallon oil can.

The motor and burner coupling are fine because under the one-pipe system I have adequate pressure.

So what on earth can the problem be?

- Norm

Donny

air

could you be sucking air in someplace?

John@Reliable_10

How about..............

the amount of oil in tank? If return line is above the oil level in tank air could get into pump, when you removed return line you solved the air problem.

Unknown

The return line I had on the flexible line in the 5 gallon oil can was definately in the can all the way, also when I pulled it out to check the flow through that return line the nozzleport still had no pressure.

Unknown

in the 5 gallon can test both the supply and return lines were completely in the oil. the only fittings that existed between the lines and the pump during that test were a couple of 1/2" flare fittings and some IPS piping to the pumps inlet and outlet.

Unknown

B pump flow chart

I am currently looking this flow chart over, paying much attention to the bypass plug and the diaphram valve.

But I cant help but remember that at some point in time the old pump with the original supply and return were working.

If there was anything wrong with the pump, a new one should have solved the problem,... but it didnt. That leads me to believe the problem is elsewhere.

Then I think about my 5 gallon can test. I eliminated the old fuel lines but still had the problem.
But if that wasnt madening enough, everything works fine with single-pipe.

Its driving me crazy

- Norm

http://www.suntecpumps.com/PDFs/Form 2720 - Model B Two STage Flow Diagram.pdf

Al Gregory

Is there another burner running off the lines coming out of the tank too?

Unknown

Nope. One tank, one burner.

Weezbo

Funky solenoid...

Weezbo *~/:) For sure.

Unknown

There is no Solenoid valve on the top of this B pump, or the old one.

Rich P.

Total Gear Suction Capacity

Just a thought, when using a two pipe system the fuel pump moves its total gear capacity roughly? 17 gallons per hour
when you get to a one pipe you only move the firing rate.
I have converted many a two pipe to a one pipe just because of what you say( dribble out of nozzle line) it always worked.
Of course the question is why the new pump?
maybe pumps not new? Or possible restriction in suction line?
Leave it one pipe see how it does
Good luck

Rich P.

EBEBRATT-Ed

Sounds pretty strange-what about hooking it up with a pressure and vacum gages and running it on one pipe and then two pipe and then compare

Ed

Unknown

Ill definately hook up a vacume guage to the oil line, thanks. Im suprised I didnt do that already.

One thing comes to mind about the pressure though. I dont think Ill get eny reading on the pressure port of the pump since I get no pressure in the nozzleport on the two pipe set-up. Its worth a try though. More information to figure the problem out with.

Anyone know if any vacum issues at all can affect fuel being sent to the nozzleport?


Also the kicker to this whole thing,.. the unit has been running fine with its currrent set-up for years. This isnt a new installation. Just one day, all of a sudden, no heat. Enter Norm: stage right

John@Reliable_10

Norm, high vacuum can cause.............

the oil to "vaporize" in the pump, which may cause vapor lock in the pump or line. But with what you have said you have done, and me rereading all posts it really sounds like a bad coupling ,shaft or motor maybe. Did Mark give you this call? P.S. If all else fails I would leave it one pipe and install a tigerloop. John

Unknown

The coupling is new, I replaced it when I put the new B pump on.

If the motor isnt quite comming up to 3450RPM is there any kind ove valve in the pump that requires centrifugal force to open and send pressure to the nozzle port?

Looking at this pump flow chart I see a diaphram valve that has a connection to the nozzleport. Maybe the motor comes up to 3450 on start up but then drops down in RPM enough to close the diaphram valve?

Does the diaphram valve work this way? I have never gotten into the guts of a pump like this before.

That explination sounds good, if that diafram valve works on centrifugal force.


After the holiday I will try changing out that motor.


Edit: Just thought,.. if it works on single pipe and not on double, and the motor not maintaining 3450rpm is the issure,... it shouldnt work on single pipe,.. shoult it?

According to this flow chart, From the pump inlet If I were oil I can go through the second gearset, through the cone valve and into the nozzleport that way,.. but to be honest I dont have enough intimate knowledge of how a pump really works to make any real sense of this flow chart. Right now I just sound like a crazy person.

Norm Harvey
Independent Burner Service
Weymouth, MA

EBEBRATT-Ed

Motor not up to spped is definatly an issue. Pressure reg in pump wil not let oil go to nozzle if not enough pressure. Usually takes about 80 psi to open reg when set at 100 psi--what are you set for -maybe to high. Maybe this is why pump will deliver oil on one pipe system but not on two pipe. on a two pipe the pump must deliver more oil and possibly cant build pressure. I suspect a high vacuum condition.

Ed

steve_93

Had the same problem with a motor... not staying at 3450 and dropping the pump out.

joe_14

just had same problem

with a new furnace we installed. old one ran for years with two line system.new on wouldnt run called suntec they said to run on line we did it works but running high vaccum. suntec said problem when two line is the total gear suction capicity. they sugested to us to use a booster pump which we did, problem soloved

joe.g

Wayne_16

plugged supply or return line?

> Here is the situation:

>

> A unit heater

> suspended from a ceiling approx 12 feet above the

> floor. This unit has a Suntec-B pump with 1/2"

> supply and return lines. No heat.

>

> My

> troubleshooting steps;

>

> 1. Point the jet line

> into a bucket and observe oil spraying from the

> jet line before a brief cavitation type noise is

> heard, and fuel stops spraying from the nozzle

> line.

>

> 2. Prime pump through the prime port and

> observe good flow with no air. Repeat step #1

> with the same results.

>

> 3. I hook up 1/2"

> flexible oil lines into my 5 gallon oil can and

> repeat step #1. Same results. I observe good

> flow from the return line.

>

> The pump is pumping

> oil, yet nothing is going to the nozzle port.

> Except briefly on start-up.

>

> 4. Replace the

> pumb with a new Suntec-B pump. Repeat step #3.

> Same results.

>

> This iw where I sit on a 5

> gallon pail and think for awhile.

>

> %. Just for

> fun I remove the return line and bypass plug, and

> plug the return port. Prime the pump through the

> prime port and fire the unit. With this one pipe

> set-up I have continuous pressure to the

> nozzleport and the unit runs fine.

>

> 5. I hook

> up the old supply line and observe proper

> operation.

>

> And this is the point where I

> scratch my head in wonder.

>

> Heres my

> thinking;

>

> The old pump must still be good if I

> am having the same problem with the new

> one.

>

> The existing return line cannot be the

> problem because the problem existed with my

> flexible line in the 5 gallon oil can.

>

> The

> motor and burner coupling are fine because under

> the one-pipe system I have adequate

> pressure.

>

> So what on earth can the problem

> be?

>

> - Norm

Wayne_16

plugged supply or return line?

If the system has been operating for some time and now will not work. I would check the supply line for an obstruction, plugged filter at the tank, debris in the intake pipe/shutoff valve.

The difficult takes more time, thats why you are the professional.

Wayne