Sunstrand two stage pump

nevele

I have a sunstrand pump that is losing oil pressure and cavitating mostly on high fire. (H3PB-B100-6) Does anyone know if a pump can be operating good on the suction stage and not being able to maintain pressure on the second stage.

Don_197

any restriction in the fuel line can cause that (plugged inlet strainer or plugged inline fuel filter or sludged up oil line.) those are just the most obvious culprits......@Icesailor is one of the many older than dirt oil burner experts here (wink wink) .....I'm sure there are many more conditions that can cause that

EBEBRATT-Ed

Put a vacuum gage on it and see what you get. Anything over 12" or so could be a problem depending on pipe size, tank location and oil level. Check the oil filter. The vacuum should be rock steady, if not you could have a suction leak. You can also pull the cap off the pump and clean the strainer inside. You may want to be sure to have a spare gasket.

Starved on high fire is usually a restriction or a suction leak

icesailor

Is it single pipe or two pipe? What burner is it on? You have a pressure gauge on the supply/outlet to the nozzle? Its OK on low fire but drops on high fire?

Cannister type filters on the supply? Spin-On types are a wonderful thing with their 1/8" NPT tapping for a vacuum restriction gauge. You have a vacuum gauge on the supply> Restriction and high vacuum will cause outgassing of the fuel and pumps don't like to pump air. What's the GPH on Low and High Fire?

If it starts and runs fine, goes to high fire, and runs fine for some period and starts dropping off, it is usually a restriction. Vacuum leaks are a form of restriction because the pump needs more energy to create higher vacuum levels to overcome the form of resistance that the leak is. Another common place for vacuum leaks is at pump shaft seals. If there is any sign of fuel vapors at the face of the pump seal, look for a leak. It won't show up on a vacuum gauge unless it is a two pipe system and it is loosing prime while off.

If all else fails, a Tigerloop can be a wonderful thing. They will run at over 40 GPH when you twin them up properly.

nevele

Its a carlin burner 801CRD . Low fire nozzle is 5.5 gal high fire nozzle 4.0 gal pump pressure 150 psi firing rate 11.5 gph. There is a tiger loop on the system . The old one was completely full with oil so I put a new one in . New oil line from the tiger loop to the pump. I have the pressure guage installed where the bleeder is normally threaded in. The vacuum guage is installed on the pump in the alternate suction port. (left side top). I opened up the 1/2 " copper line from the tiger loop back to where it tees into a large line coming from the oil tank ,blew through it and its clear.I checked the firomatic valve just before the tiger loop and its wide open. Where the 1/2" copper tees in there are two more burners connected beside it the same way and they are working fine. A large filter is on the main coming from the oil tank and it serves all three burners. This setup has worked for many years. There are no signs of oil leaking anywhere. I replaced the strainer in the pump also. Could the pump be faulty even though its creating a high vavuum?

Thanks a lot for your comments.

EBEBRATT-Ed

What's the vacuum?

EBEBRATT-Ed

You need to put vacuum and pressure gages on this and tell us the readings and how steady they are. The only way to troubleshoot without guessing

nevele

The pressure guage reads 150 psi until it starts to act up and then it drops to 125 100 etc until the flame goes out. The vacuum is 15 or 16 inches on low fire and closer to 20 just before the flame goes out.

EBEBRATT-Ed

Vacuum is way to high. I don't know what is going on can you check the vacuum at one of the other burners that are running??

You need to find what and where the restriction is at. Your never going to run properly until you find it. It's not the pump. The pump is trying to do it's job. If the vacuum is high at the other burners then the main line is restricted as you said they are teed together.

The other burners may be taking the oil from this burner, the oil will take the path of least restriction. This pump is probably ok but the other burners may have less piping, fewer elbows so when you reach a " crisis vacuum--which you have" they are fighting each other for oil.
need to get the vacuum under 12 if possible

icesailor

""" There is a tiger loop on the system . The old one was completely full with oil so I put a new one in . """

How many Tigerloops on the system? There can be ONLY ONE Tigerloop for each burner. They can't be ganged up and one serve for multiple burners. The top is supposed to have some oil in the top. Sometimes, it is full, sometimes not.

""" New oil line from the tiger loop to the pump. I have the pressure guage installed where the bleeder is normally threaded in. The vacuum guage is installed on the pump in the alternate suction port. (left side top). """

On a 2-ppipe system with a Tigerloop, that is not a good location for a vacuum gauge. It belongs outside the Tigerloop where it is marked "From Tank" where the Firomatic goes.

How old is this Tigerloop?

Does the Tigerloop being used look like the one in this PDF photo with a cap on the top or does it just have a clear plastic top with a point of plastic on the top and no covering cap? If it doesn't have the cap, it might be a very old model. They had some years ago (way out of warranty) that had a problem with locking up on a vacuum lock. It would do exactly as you describe. It would run for a period and stop. Sometimes, you had to leave it off for a while and then sometimes, break a line to release the vacuum. You have to replace the Tigerloop.

http://www.westwoodproducts.com/images/Tigerloop_is_reliability_US.pdf

If you read the PDF for the single Tigerloop, it explains how they work. They're good for 20 GPH and 30 GPH returning back. But they can't run more than one pump burner. They can probably all suck off a common supply, but individual suction supplies would be best.

nevele

The tiger loop is brand new and the same as the one in the pdf with the black plastic disc on the top.
Each of the three burners has its own tiger loop.
When the other two are running the oil in the tiger loop for that burner is steady as can be.
They are all setup the same with 1/2" copper to each burner, tiger loop ,firomatic valve. The burners are close together so there's no long runs or anything.
The burner that i'm working on acts the same whether the others are running or not.
When I get back to it ill try installing a vacuum guage outside the tiger loop .
The three burners are connected to the main line into three black iron tees side by side with a ball valve off each tee and the 1/2" copper tubing that runs to the firomatic valve ,to the tiger loop and then to the fuel pump.

billtwocase

This would have been best posted in the oil heating section. Your high vacuum is telling you restriction. That is why your pressure is dropping off. Pics would be a big help of your fuel supply, filters, lines, valves, lift, runs, etc. You mentioned a ball valve. Check to make sure it isn't broken inside. I have had that happen oil or water. Was the Tiger Loop installed due to previous problems with fuel supply? Where is the "T" that branches off to supply the other units? What valves and filter at the tank? Tank size, out of tank nipple size for supply, etc?

icesailor

One filter at the tank for all three burners? When all three are running, that's almost 35 GPH. If you have a Fulflo, it needs to be a 10" filter. Does the misbehaving burner do this all the time? Or just when the other burners are running? Any possibility that the by-pass screw came loose? (I've never seen one do it, there's always a first time). If there is only one line from the tank, and only one pump gets high restriction vacuum, its a scratcher.

You sound like you know what you are doing to be working on those bomb proof 801CRD burners. Any possibility that the offending burner oil feed has a high spot and is getting air/gas vapors that cause a Vapor Lock and high vacuum?

Photos?

I was called to look at something similar once that sounds similar to yours. Just not all the big burners.

nevele

Ill try and get some pics the next time I get back there. It's the first time I worked in this building. The tiger loops have been installed for years and as far as I know it was all good until a month or so ago. Other people have checked it out before me.
I was expecting to see a restriction somewhere so I replaced the tiger loop and the flex line from the tiger loop to the burner pump. I removed the firomatic valve and its wide open I disconnected the 1/2" copper oil line and blew through it with no problem. The only thing left is the ball valve where the 1/2" copper is connected . There are three 3/4" black iron tees side by side and each has a ball valve and from there the 1/2" copper to each burner.I plan to install the vacuum guage near the ball valve to read the vacuum at that point (thank you ice sailor)and then I might get a five gal. bucket of oil and put the copper into the bucket and see how it works. The filter is about six inches long screw on type.I don't want to do anything to interfere with the other burners they are working good and its an extreme winter here and there are a lot of older residents in the bulding.

EBEBRATT-Ed

That screw on filter may not have enough flow rate for all three burners.

I am going to say something that doesn't make a lot of sense. You may find that all three burners have a high vacuum and the two that are running are "hanging on a thread" I know it make no sense but if your running that close to the "end of the string" it could be one or two extra fittings or something slightly different in the piping geometry that pushes that one burner over the edge. There fighting each other for oil and the trouble burner is the loser

icesailor

"" I was expecting to see a restriction somewhere so I replaced the tiger loop and the flex line from the tiger loop to the burner pump. ""

You replaced only one line? There are two from the Tigerloop to the oil tank. Where's the other line? Did you check the by-pass plug to be sure it was tight?

It is still possible that you have a bad fuel pump. You need something like a Mitco "Qwik-Chek" pump tester, although interesting to connect.

You need to figure out how to by-pass the controls ( you can) and fire the burner so it thinks it is running. Have both low and high fire lines pointing in to a bucket and run the burner. On low fire, notice how much is being pumped. Then, when it goes to high fire, watch it drop. Either the pump is bad, or the pump strainer is dirty. If not, and you put a vacuum gauge on the inlet of the Tigerloop, and the vacuum goes up as the volume goes down, you have a restriction somewhere. Most have a low/high fire switch. Switch it into low fire. Then, switch it into high fire when you want. Its the same pump that just by-passes more fuel when on low fire.

Two Stage pumps are different than single stage pumps. I had a Suntec Pump Manual that showed the difference. Without having the manual, and because the burner ran properly for so long, it is more likely that the part that brings the second stage has an issue.

Post a photo of the burner and Tigerloop connections.

nevele

I put the supply and return lines from the burner in to a bucket of oil and it worked great. Low vacuum and steady oil pressure. So I did install a vacuum guage outside the tiger loop right next to where the copper connects to the black iron tee and the vacuum reading was 15 or more. (same as at the burner with the tiger loop and everything back in place) There was already a vacuum guage installed on the other side of the filter and it was stuck at 1 so I replaced it. So the vacuum was up to 20 with the burner running on high fire and at 4 on the other side of the filter .I put in a new oil filter and the problem was solved. The vacuum on both sides of the filter is low (4). Burner is working great.
The other two burners are a big weishaupt on a unilux boiler and a riello on a new Yorker for domestic hot water. Total firing rate is probably around 40 gph when they are all running. I don't know why these other two were working perfectly with the same high vacuum and plugged filter.
I left the two gauges on either side of the filter in place so they will know when the filter starts to plug up.
Many thanks for your comments and suggestions.

icesailor

Do yourself or someone else a favor. Replace those filters with spin-ons with restriction gauges on every filter and burner. The restriction gauge shows you the health of THAT filter, and no other.

When you get up into equipment as expensive and advanced as that, its no time to start getting cheap. That equipment adds to the gross profit of the company, whatever they make. Add that up, and what the company would loose if all those boilers went down because of dirty filters. Quality filtration is a cheap date. And doesn't ask for anything in return.

EBEBRATT-Ed

As I posted earlier, oil like steam or water takes the path of least resistance. Why two burners will run and the other one wouldn't--different pumps, different piping, different flow rates???? Working with oil lines in a vac is different. Things don't always act like we think they should. Glad you found the problem.