Aux tank/boost pump help

JoshNJ

I have 3 forced air furnaces and two oil burning water tanks for a total of 5 burners on my system. 

1 furnace (new) and 1 water heater are installed far from the main tank and have a tiger loop setup (no return feed to main tank)

The main furnace room has the primary oil tank as well as an auxiliary tank that is near the furnaces and water heater. 

It seems the auxiliary tank has somehow lost prime. I suspect when the techs were installing the new furnace in the other room. 

The furnaces and water heater that run off of the aux tank are all in lockout and have air in their lines when I bleed them, the aux tank seems to be empty (from knocking on it, no way to visually tell) and the boost/transfer pump runs nonstop until its thermal breaker trips (takes a long time). 

Here are a few pics. Any help or guidance on how to prime this system would be very much appreciated!

JoshNJ

Here is a poor diagram to try to help explain. Part of me wonders if that aux tank is even needed. All of the units are on the same level as the main tank

STEVEusaPA

First make sure all of your firomatic valves are working and opened. Work the one in front of the filter and the one after the pump, making sure the wheels havent failed and they aren't open.
Then I would fill that filter with clean oil, replace, and try to get it pulling that way.
If that didn't work, I'd probably try to connect a push/pull pump onto the outlet of the filter, and see if I can get some oil up past the filter. Then close the valve before the filter, then reconnect and turn the pump back on.
Hopefully someone didn't smoke your booster running it dry.
Also, keep in mind that pump may not be able to keep up with the 3 furnaces, especially if the day tank level is low.

JoshNJ

Is it feasible to eliminate the pump altogether do you think? The furnace and water heater that are clear on the other side of the house don't even rely on it. I'm somewhat surprised this type of a setup is in place given the tank and all burners are on the same level (all in the basement).

JoshNJ

One other thing I failed to mention, when we purchased the home it was shortly after a sale had fallen through because the prior buyer was insistent they remove a buried oil tank and replace it with an above ground tank. They did that work after that sale fell through. I can tell the pump was installed BEFORE that work was done, I'm curious if it wouldn't be needed with an above ground oil tank.

Is there a rule of thumb regarding a number of burners that can feed off a 1/2" primary feed line (branched to smaller lines) before needing some kind of booster?

JoshNJ

I found this diagram in an old box, it very well sums up the system that runs off the aux tank and pump  

Jamie Hall

Ah. Now the day tank (auxiliary tank) makes sense. With that tank priming the various burners would have been rather simple -- without it, frankly a pain in the neck. You don't really need it.

Someone else will comment (I hope) on the capacity of the feed lines. My own opinion, though, is that I'd much rather see independent feeds to each burner, each with their own shutoff and filter at the tank.

JoshNJ

What is interesting is that the burners all pre-date this lift system. My working theory is at some point they had issues with that underground tank and priming and put this in. Then when they had the underground tank removed and replaced with the one now in the house they just hooked it up as it was to make the job easier. What’s so weird about it to me is the burners that have the longest run to pull oil don’t actually get support from the aux tank. Only the ones right in the room which have very short runs. 

See this picture I marked up
Green: Feed from primary tank.
Red: Return to primary tank
Blue: feed from AUX tank to 3 burners in the same room/area as the AUX tank
Unmarked: is from the pump outlet up to the AUX tank
Yellow: feed from this room all the way across the house to two other burners on a single tiger loop. Notice that this is BEFORE the AUX tank! 

Why would they have this aux tank here supporting the burners with the least pull distance?? Have to assume it was from when the tank was buried and this room actually had the longest pull distance. 

Only question in my mind is if this room can function without that thing and without extra lines being added

STEVEusaPA

What is the relationship between the fuel pump and the bottom of the oil tank on each unit?
If everything is gravity and/or, not too much lift, I’d probably come out of the tank in 1/2”, with a large general filter with vac bolt, into a home made manifold near the tank made out of 2” pipe. For each branch, 3/8” copper, a spin on filter, and if gravity, an OSV no more than 3' above each burner.
And only because of run distance, ease of bleeding, and reducing nuisance lock outs, tiger loops on every burner.
Of course piped to code with all appropriate valves and accessories.
Then you could ditch the day tank booster pump. But if you do, sell that control and tank on eBay (or send it to me for helping), as they’re good as gold.

I agree with your theories. The day tank was only because of the underground tank to eliminate problems with high vacuum.
If any of those far away burners need more capacity, you could bump them up to 1/2” and/or use a 2 stage pump.
If you show me a linear line drawing of each fuel line, tank to burner, showing measurements and elevations, I could check capacities.
Are all burners drawing off on one tank? If so, what kind, how many gallons?

EBEBRATT-Ed

I would keep the booster pump. With a Roth tank pulling off the top and feeding multiple burners I think you will have issues without it. JMHO. In you second picture down near the firomatic valve on the pump you will see a 3/8 hex barbed fitting. You open that with a 3/8 box wrench to bleed the pump.

If the pump has been running dry with no oil going through it the pump could be toast by now.

JoshNJ

The pump itself is fine, that's confirmed. The challenge is oil flow with the pump not supporting everything... This chart I found seems to suggest that even at 40gph of No 2. heating oil I'd be ok with 1/2" pipe (assuming OD but it doesn't specify?) in my system. Most of the burners are 1-1.25 GPH which even with them all running at once would only be 5-6.25 GPH of draw through every burner. All of the pipe in the house is 1/2" then steps down to 3/8" through various manifolds to feed the burners directly (which I assume is standard):



If I think about the old system that was in place when this pump was installed it was installed at the farthest point from the underground tank.

I'm not an expert on any of this by any stretch but this pump and aux tank seems like an unnecessary complication I'd love to eliminate (especially since it acts up) currently I believe the pressure switch on it is failing.

JoshNJ

STEVEusaPA said:

What is the relationship between the fuel pump and the bottom of the oil tank on each unit?
If everything is gravity and/or, not too much lift, I’d probably come out of the tank in 1/2”, with a large general filter with vac bolt, into a home made manifold near the tank made out of 2” pipe. For each branch, 3/8” copper, a spin on filter, and if gravity, an OSV no more than 3' above each burner.
And only because of run distance, ease of bleeding, and reducing nuisance lock outs, tiger loops on every burner.
Of course piped to code with all appropriate valves and accessories.
Then you could ditch the day tank booster pump. But if you do, sell that control and tank on eBay (or send it to me for helping), as they’re good as gold.

I agree with your theories. The day tank was only because of the underground tank to eliminate problems with high vacuum.
If any of those far away burners need more capacity, you could bump them up to 1/2” and/or use a 2 stage pump.
If you show me a linear line drawing of each fuel line, tank to burner, showing measurements and elevations, I could check capacities.
Are all burners drawing off on one tank? If so, what kind, how many gallons?

Tank and all burners are on the same floor of the house. There is "lift" as the 1/2" feed line coming out of the main tank is going in from the top, that said, once primed most of the burners themselves would be below the fill line of the tank until it's down about 1/3 to 1/4 of the way full (which rarely happens) - I'd assume this ineffect creates a siphon so oil should WANT to flow to the burners when they call for it and would not be much of a heavy lift even when the tank is low. The highest above the main tank floor any burner is would be no more than 3 feet, some are actually slightly below it.

The lift pump (not sure the right name by suntec seems to have specs that say it can generate up to 300psi. The Aux tank it lifts to appears to be in the realm of 5-8 gallons capacity but I would assume is at most half full at any given moment. (pressure switch seems to be set around 6" water column, although I think it's failing)

I relabled my poor diagram with pipe sizes and approx distances. Hopefully that's helpful?

All burners off one tank it's a Roth 400 gallon tank.

JoshNJ

Sorry forgot the updated diagram

JoshNJ

For those interested I've removed the pump and aux tank and set up each appliance with a tiger loop of it's own. Everything is now functioning without issue.