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View Full Version : Oil Hot Water Heater Shuts off every two days! Help!



truthfreesyou
12-10-2008, 10:19 PM
Hi, I am new to the forum, and I am very frustrated with my problem:

Every two days, my oil fired hot water heater shuts down. I have to hit reset manually, and then it works perfectly for two days. Then it shuts down again.

(I don't know if this is related, but I also have the problem of hot water coming out of the cold faucet for the first 15 seconds from every sink in the house, but I am not worried about this right now, unless these two problems may be related.)

BUT MY MAIN CONCERN IS THAT I GOTTA GET THIS BOCK OIL HEATER TO RUN CONSTANTLY, AND NOT TURN OFF EVERY TWO DAYS!! ANY IDEAS????

Gary Swart
12-10-2008, 10:23 PM
If it was gas, I'd suspect the thermocoupler, but I don't know if an oil fired heater uses one.

Cass
12-11-2008, 01:24 AM
It sounds like you might have a bad thermostat and the high temp cut off is working and shutting it down...if it is over heating and you don't have a expansion tank your thermal expansion may be the reason why you are getting hot water on the cold side of the faucets for 15 seconds...

nhmaster
12-11-2008, 04:08 AM
If you're hitting the re-set button to get it started then there's a problem with the oil burner and you need to call a service tech. It could be any one of about 20 different things.

Redwood
12-11-2008, 06:33 AM
I would concur with NH Master that you need an oil burner service tech.

The hot water for the 1st 15 seconds is hard to say why. Do you have a hot water recirculation system?

truthfreesyou
12-11-2008, 09:22 AM
i have had multiple service calls to deal with this. they have all tried different things - cleaning the lines, pumping oxygen through the fuel lines, etc. but it hasn't worked.

the interesting thing about the problem is that it usually happens when the heating furnace goes on. (i.e. it doesn't happen over the summer, only during the winter months when i am also using oil heat)

i suspect that somehow the two machines are competing for the same supply of oil, and the furnace "wins" the fight, therefore causing the water heater to shut down as if it didn't have fuel.

does this make sense? i am not a tech, but i suspect this...

anyone??

wallyworld
12-11-2008, 11:00 AM
i have had multiple service calls to deal with this. they have all tried different things - cleaning the lines, pumping oxygen through the fuel lines, etc. but it hasn't worked.

the interesting thing about the problem is that it usually happens when the heating furnace goes on. (i.e. it doesn't happen over the summer, only during the winter months when i am also using oil heat)

i suspect that somehow the two machines are competing for the same supply of oil, and the furnace "wins" the fight, therefore causing the water heater to shut down as if it didn't have fuel.

does this make sense? i am not a tech, but i suspect this...

anyone??
There is a single oil line that tees off to each unit? That doesn't seem right, if one was on and the other off it could suck air from the off unit. Must be some check valves in there?

Cass
12-11-2008, 11:08 AM
Chech the gal. / hr. rating on the furnace nozzle and the rating on the WH...add them together and then see if you can figure the amount that will gravity feed through the line...Do you know what size the feed line is coming from the oil tank?

nhmaster
12-11-2008, 03:05 PM
If you have two appliances teed off the same oil line there is a very real possibility that the oil line is not large enough for both units, especially if it's only 3/8". One unit will pull through the other and if both are running they can pull enough suction to cause cavitation in the oil line.

truthfreesyou
12-13-2008, 09:23 AM
If you have two appliances teed off the same oil line there is a very real possibility that the oil line is not large enough for both units, especially if it's only 3/8". One unit will pull through the other and if both are running they can pull enough suction to cause cavitation in the oil line.

i think this is the problem. the service tech is coming today to install a preference switch, (or something like that,) which automatically gives preference to the water heater when both are pulling at the same time.. he said this will prevent the shut-downs. have you heard of this?

truthfreesyou
12-17-2008, 09:48 PM
help!!!!! the service tech came and installed a preference switch which temporarily shuts off the furnace when the hot water heater activates, so the furnace wouldn't suck the fuel from the heater....

IT DIDN'T WORK!!!!! THE THING HAD TO BE RESET THE NEXT DAY, AND THE DAY AFTER, ETC....

could the problem be electrical?? i am at my wit's end, because nobody can figure this problem out.. the machine is running perfectly, has been cleaned, serviced, etc.. just this damn shutoff problem.

could the problem be that the machine is tripping the electrical fuse and therefore shuts down? i don't think so, because i never have to change the fuse or flip the switch, just hit reset... but i just don't know what to do!!!

help!!!!!

Cass
12-18-2008, 04:16 AM
What kind of reset is it thermally activated or strictly electrical...has the reset button been replaced?

truthfreesyou
12-18-2008, 06:58 AM
i am not sure, but the reset button works. the unit goes back on, then shuts off later.

Cass
12-18-2008, 07:22 AM
If it is thermally activated and it is going bad that may be the problem...is the water ever super or excessively hot before the reset shuts off?

Verdeboy
12-18-2008, 12:19 PM
It sounds like you might have a bad thermostat and the high temp cut off is working and shutting it down...if it is over heating and you don't have a expansion tank your thermal expansion may be the reason why you are getting hot water on the cold side of the faucets for 15 seconds...

I agree 100% with this answer.

truthfreesyou
12-18-2008, 12:48 PM
so are you saying that after the machine fills up with hot water, the thermostat is kicking it off? interesting.

also, i do agree that these two problems are related, and therefore this could be kicking off the machine..

i am going to print this out and when the tech guy comes tomorrow (again), i will make sure he reads this...

more updates tomorrow!

thanks so much,
mitch

truthfreesyou
12-18-2008, 01:26 PM
If it is thermally activated and it is going bad that may be the problem...is the water ever super or excessively hot before the reset shuts off?

one thing i know is that when the cold water faucet turns on, the first water that comes out is usually scalding hot... then it gets cold... this could support your idea that the problem is the thermostat, and that is why the unit is shutting itself down.

but would this make it go to reset or just temporarily shut down??

- mitch

nhmaster
12-18-2008, 03:21 PM
Neither the thermostat nor the high limit have anything to do at all with the primary control safety circut. They are totally separate circuits. Not sure what a prefrence switch is, never heard of one. If the oil lines are 3/8," switch or no switch, there is too much restriction there and the oil line is cavitating. In fact, installing check valves may have worsened the suituation due to the added restriction of the ball check.

Verdeboy
12-18-2008, 04:14 PM
so are you saying that after the machine fills up with hot water, the thermostat is kicking it off?

I think he is saying that the thermostat is no longer working properly, and the water is getting so hot that a safety high limit switch is turning it off.

Redwood
12-18-2008, 04:34 PM
The high temp will not cause the burner to go out on reset!
As NH Master stated they are separate controls.
The high limit and aqua stat interrupt the 120 VAC supplied to the burner assy.
The oil burner primary relay recieves this voltage and distributes it as needed for the burner to operate unless the burner fails to fire at which time it goes out on reset.

Take a read here...


Before teeing into any existing oil line, check the vacuum
on the existing burner by installing a vacuum gauge in the
1/4” inlet port or the vent opening. On a two-pipe system, a
single stage pump should not exceed 8” Hg. vacuum and a
two-stage pump should not exceed 15” Hg. vacuum. If the
vacuum readings do not exceed these limits, the new water
heater can be connected to the existing lines.If the heater
performs poorly, recheck the vacuum reading with all units
in the system operating. A high vacuum reading indicates
too much resistance to proper fuel oil flow, possibly caused
by a clogged filter, restricted shut-off valve, kinked tubing,
obstructed oil line, excessive lift, too long a horizontal run
or an undersized oil line (see Tables 8 and 8A).

Bock Water Heaters Engineering Manual (http://www.bockwaterheaters.com/technical/engineering_PDFS/2-GeneralInformation_8_06.pdf)

truthfreesyou
12-20-2008, 04:41 PM
update: my service guy came and installed a new transformer. he said the porcelain insulators over the wires were cracked, or something like that.. either way, it has now been working perfectly for two days!!!! hooray!! (so far...)

does this make sense? or am i lucky it is working?

Verdeboy
12-20-2008, 05:12 PM
Are you still getting scalding hot water out of your cold tap?

truthfreesyou
12-23-2008, 11:05 AM
Are you still getting scalding hot water out of your cold tap?

we are still getting hot water for the first 10 seconds or so, so i have to say yes to your question. however, the machine is not shutting itself down anymore, so the main problem is fixed.

i think these are separate issues, and the new transformer fixed one...

and my tech told me that the machine does not have a thermostat, so it couldn't be a bad thermostat.

WV Hillbilly
12-23-2008, 11:26 AM
You said you have had multiple service calls for this problem . If the problem is now solved the first service person should have found the problem . Cracked porcelain on the transformer or electrodes is not hard to see .

Verdeboy
12-23-2008, 11:29 AM
The only thing I can think of is that heat is escaping from the tank to the cold inlet, and that hot water is mixing with your cold water supply for the rest of the house. Ask your maint. tech about installing heat traps on the tank.