Water heater stops when boiler fires

bruce_21

I just changed out an old peerless steamer for a new one. Now the Bock water heater beside it looses its flame when the boiler kicks in. They have been working fine for years until now. The nozzle in the boiler (Beckett AFG burner) is now a 1.50gph, it had been a 1.25gph in the old boiler. The Bock has a Carlin EZ with a .75gph nozzle. Both are two pipe since the tank is outside underground. The oil line is 1/2" O.D. from the tank into the basement then a tee and 1/2" od to the boiler and 3/8" to the water heater.



I put a new nozzle and filter on the water heater, because it was shutting down. That's when I noticed that it would fire nicely until the boiler kicked in. Then it will loose its flame just like it had no oil.



I'm very puzzled by why this should happen now. I checked the lines carefully to see if we might have stepped on them during the new boiler install. they seem fine, we had gently bent them out of our way.



Thanks in advance for any help or suggestions.

Robert O'Brien

Don't waste

Don't waste your time with check valves,no need a for a check valve on any oil burner. A preference relay is the cheap way out,Tigerloops are the best way out

billtwocase

losing prime

I'd start with by checking the pump strainer in the water heater, if it is a Suntec pump. Next vacuum test the pump. Is there a common filter? Hopefully not a Fulflo installed, air leaks are common for those. Also i'd check to see if both pumps have the by-pass plug in if 2 pipe system. If all checked out, If it was my baby, I'd make it a 1 pipe system, make the return the feed for the water heater, remove the by-pass plugs, and return lines. Two pipe systems run high vacuum, and filter too much oil needlessly. If there are no air leaks, one pipe is all you need. Another thought is flare fittings should be present, check packing on any gate/globe valves, or even sloppy stemmed fireomatic valves. All will cause an air leak

Patchogue Phil_2

gph increase

The nozzle in the boiler (Beckett AFG burner) is now a 1.50gph, it had been a 1.25gph in the old boiler



Bruce I am curious,  why such a big increase in the nozzle gph?  Usually new systems have lower gph because of better windows,  insulation,  air sealing etc.  Unless load has been increased by additional sq feet to heat.



There might be a kink or restriction in the supply tube somewhere down the line,  and the old total gph of 2.0  (1.25 plus 0.75) is the max able to be sustained.   Maybe the old nozzle was smaller be cause of this?  You could be chasing an old issue.

icesailor

Two pumps:

A pump will draw product from where ever it has the least resistance. It will suck air through the old seal in the water heater pump.

I would add a Tigerloop to each burner, and use the other return line of the two pipe system for the other burner. Making both lines a primary suction line for each burner. If one line has  a air issue, you will see foam in the affected tigerloop a lot. Not so with the good one.

You don't want to be running all that return oil back to the tank. And filtering gallons and gallons of oil that you don't use.

Put in the Tigerloops.

I've had all kinds of problems with having two burners off the same outlet of basement tanks and that was gravity.

What you have is nothing but a box of trouble.

bruce_21

Thanks

for everyone's thoughts and suggestions. I had had the 1.25 nozzle that came installed from the factory, but the unit wouldn't build any steam pressure and was always shutting off on the t-stat being satisfied. I wanted to be sure that the new header piping was steam tight before insulating it so I put the 1.50 in and got it tested and insulated and then more "interesting troubleshooting opportunities" arose. So the 1.25 is back in the unit now and we'll see whether the HW heater will still be dragged down or not.

bruce_21

Thanks

for everyone's thoughts and suggestions. I had had the 1.25 nozzle that came installed from the factory, but the unit wouldn't build any steam pressure and was always shutting off on the t-stat being satisfied. I wanted to be sure that the new header piping was steam tight before insulating it so I put the 1.50 in and got it tested and insulated and then more "interesting troubleshooting opportunities" arose. So the 1.25 is back in the unit now and we'll see whether the HW heater will still be dragged down or not.

icesailor

Consider this:

Bruce,

Consider this.

If the filter was dirty on the water heater, and you changed the filter on the water heater to a new one, that is what caused the problem. Remember that a vacuum is just lowering the atmospheric pressure locally. If the pump on the boiler needs say 10 (out of 100, say) units of suction to suck from the tank, and the dirty filter provides 12 units of restriction that the vacuum must overcome. The boiler pump must overcome that 12 units or it will get product from the tank. If you clean and change the filter and it then only provides 4 units of restriction, the boiler pump will apply 10 units of suction to the whole pump. It will then allow atmospheric pressure to enter the suction system by any way it can find, Usually through the water heater pump shaft seal.

At least, that is how I figured it out.