Warning on using Sid Harvey's day tank P239-1 pressure switch P239-11
Don't know how many people still have a day tank in their system using the Sid Harvey P239-1 system but I recently had the pressure switch P239-11 failed on me. The pressure switch, which is a simple diaphragm connected to an electrical switch, is poorly made such that when it fails, the heating oil spews out of its opening and floods the area of day tank. Worse yet, when the switch fails, it fails so that the electrical pump is turned constantly on, pumping more and more of the oil to the area, and it never stops. The system is poorly designed and should have been setup so that when the switch fails, the pump is turned off. I have since redesigned the system, and if there's any interest, I can posted my setup on this forum.
Comments
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Know this is dated but came here looking for day tank info…
The system is designed to return to the tank if the switch gets stuck…if I recall correctly.
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I just had the diaphragm with on my system and I would love to see how you reworked it.
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Sorry, my switch failed. Oil everywhere.
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Any diaphragm switch can fail. Any switch can fail but anything with a diaphragm when it fails can leak any fluid or gas (whatever is in the system out) so can gas regulators. This is less likely with other types of switches.
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The simplest fix may be redundant switches. You could have a timer to limit the pumps run time and only to run when you are typically home.
You could turn the pump on when you get cold, but that may cause other issues.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Sorry, didn't check this board in a while.
Yes, the system is suppose to return the extra fuel into the main tank. But, in my case, the return is so long that I think its prob plugged or kinked. The pressure switch is also super sensitive at 5 inches of water pressure, which is almost like breathing on it and it will turn on/off. So any return line resistance will make the system fail or blow the switch. Another poor design is the switch not being leakproof. I spoke with an engineer at techmark, the maker of the switch, and he said the switch was not made to be leakproof, as spec by Sid Harvey. So the trick is not to use the crazy expensive $650 switch and find a diesel resistant leak proof diaphram switch that triggers at 5 inches of water. The diaphram switch will also have a decent hysterises character so that it doesn't turn on or off too quickly. Also, like a previous reply above, use a timer which will shutoff the pump at about 10-15 min of run time, in case the switch fails again. Plus use a large catch basin at the bottom of the tank setup, in case anything happens. I am trialing different automotive pressure switches to find a cheap and good alternative to the sid harvey switch. I have found two switches which may fit the criterion and they're both at about the $30 price point. I am currently testing it out now and will report back.
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have you contacted Sid Harvey’s with these allegations?
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Good luck with that! Sid Harvey does not even want to sell you the switch unless you have an account with them or be a licensed professional.
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Because there Whole-Sale only.
How did you get these components?
If you feel there's an issue with their product report it, they would like to know!
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Were all instructions followed?
P239-1 Supply Pumper Instructions
MOTORIZED TRANSFER PUMP (MTP) Mount the MTP under cover and protected from water and the weather (i.e. inside a building or pump house). Choose a location that facilitates priming and service, and is as close to the main storage tank as possible. Vertical lift should not be more than 25 feet above the bottom of the main storage tank.
SUPPLY TANK Install the diaphragm switch in the branch of the supply tank return tee using the ¼” NPT street elbow and ¼” NPT x 8” nipple supplied (see Diagram 1). These fittings must be used and the switch positioned with the diaphragm horizontal, electrical connections on top. The switch settings are sealed and no adjustment should ever be made.
SYSTEM PIPING All system piping must be ½” OD copper tubing using flare fittings. Compression fittings are not to be used anywhere in the system.
RETURN LINE The return line is a very important component of this system! It must run directly between the return line fitting in the bottom of the supply tank and the main storage tank. It must be pitched down toward the main storage tank to allow any return oil to flow back to the storage tank by gravity and must terminate at the top of the main storage tank. It must have no “traps” in it and be run such that any condensation collecting in it will not freeze during cold weather (see Diagram 1). The return line must also be a dedicated line. If another return line is plumbed it must have a separate termination at the main storage tank. Under normal circumstances the return line carries no oil. It is connected to a standpipe inside the supply tank and provides the overflow path for oil should a component failure or wiring defect cause continuous MTP operation. Therefore, for safety reasons the return line must be clear, leak tight, properly pitched, and in perfect condition to provide this overflow path for the surplus oil.
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I am not sure if anyone has ever seen a day tank pressure switch fail before, but the switch is located at the lowest point in the tank system. It has a certain lifespan of two years. When it fails, all the tank oil drains out and more! One may hypothesize that the switch is failing earlier than it should and that maybe I have a block in my return line. Same can be hypothesize about how poorly the switch is made, which BTW, should not even be able directly turn on of off a 120V many amps AC motor. The point of my post is to find an economical solution and a safe solution so that we don't get heating oil all out in the open. I do have to apologize about the delay in posting the solution since I don't have an "elegant" bulletproof solution yet, as I am still finalizing the details.
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BTW, I know more about the engineering of the day tank system than I care to. I didn't setup this system as it came with the house when we purchased it. None of my local professionals seem to know or want to debug the system. They all want to rip it out and move the main tank closer to the house. So I had to resort to my DIY engineering ways. The way the Sid Harvey day tank system setup is filled with problems and prone to failure causing oil spillage into basements, crawl spaces, etc.
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Is this your basic system ? If so, I think I would try having redundant switches piped so they are above the Day Tank's fuel level line, and also on opposite sides of the Day tank or separate pipes from below the fuel line. Since if both switches are on the same pipe above the fuel level line a compromised diaphragm in one would render both useless. Is your Day tank above the Main tank as pictured here so if the Day tank over fills it would gravity drain back to the Main tank ?
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Redundant switches are a good idea in theory. However, if one fails how do you know? The system will appear to run normally on the remaining good switch. Redundancy is good for overall system reliability if there is a monitoring system to warn of a single failure. Don't ask me how I know this.
John
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Hello JDHW,
The Day Tanks I once worked on were much more sophisticated and were not used for residential oil heating service.
With yours, am I assuming correctly when the fuel level drops (pressure drops) the switch closes turning on the pump ? Pressure opens the switch. No relays or other electrical equipment ? Is the pressure where the switch changes state adjustable ?
I would put the switches above the fuel level line, so a compromised diaphragm can't leak fuel out.
The redundant switches would be wired in series. If one fails closed (compromised diaphragm, no pressure) the other will still be open. Possibly neon lamps could be wired as a status of each switch so you know which switch is closed when it should not be.
If you really want to get fancy Dwyer Magnehelic Gages (one gauge for each switch or one gauge in differential configuration) can monitor the pressure applied to the fuel side of the switch's diaphragm.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Yes the diagram shown above is the setup to the Sid Harvey system that I have. Those are all good ideas but I hate to have to modify more of the system than necessary and introduce more variable to debug. Right now, the plumbing is all the same except I have added a shutoff valve in front of the pressure switch so I can remove the switch during testing without draining the system. The only modification I have done is to change the switch and added an additional timer to only let the motor run for maximally a certain amount of time, thereby limiting the amount of fuel leaked out by a failed switch. I have also added a catch basin so that any potential leaks are caught. I have also setup remote temperature monitors on my boiler to detect a cooled down situation due to fuel delivery issues.
One would think that a day tank should not be so difficult to engineer!
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Regarding the switch being adjustable, the default one is not adjustable. As stated above, when the system fails, the system is failing so that the motor is kept running. Also when the switch fails, the fuel will not only leak out from the switch, it will leak out from the tanks top vent, which I have now connected to my catch basin. Another problem I am having is diesel fumes that is coming from venting the tank to atmosphere. So my DIY solutions are far from perfect, at this point.
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I'm assuming the system is engineered to a price point, so fail safe features are limited. They do make alarm systems to monitor if a fuel tank is compromised and flooding the secondary containment structure. They are found in commercial facilities all the time. I don't know if they make an inexpensive version for residential service.
Is your Day Tank above the Main Tank ?
The Day Tank vent possibly could be extended outside, the Day Tanks I have worked with are vented outside.
If you had a flood of fuel the smell may take a while to dissipate since the oil probably soaked into the floor a bit.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
i’m still curious, was this system installed the manufacturers requirements
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I will have to vent it outside, thanks for the advice. Have to find a suitable hole in my foundation for that purpose. Regarding installation to manufacture specifications, one can only hope that any plumbing is inspected before home certification, but I doubt it. I have a home generator (using a 6bt cummins engine) that also have its own separate tank outside the property with a double wall tank and alarm sensor on the outer walls for detection of tank leakage. I agree that it is very likely that the day tank is designed with a certain price point, but a failure with the pump kept on is inexcusable.
This is actually a switch I will plan on testing:
https://www.ebay.com/itm/333389712202
Let me know what you guys think. Seems very robust, high burst pressure, has two levels of adjustment in the low pressure range of few inches of WC), many different electrical configurations (normally closed, normally open, close and open outside and inside the two dial ranges that one can easily read without a special meter) with a membrane, I think, made up of a diesel tolerant material.
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I realized that link is gone, try searching for this:
NEW UNITED ELECTRIC PRESSURE SWITCH TYPE H402 MODEL 441 STOCK 8850 0-10" WC
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I see its not cheap at $375. Still better than the rip off $700 one I guess and much better made.
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Looks like it has a Buna-N diaphragm, do you know what the P239-11 had ?
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
No idea. The engineer said it was safe to use with diesel. I did blow into a good Sid Harvey one and it really is very wimpy sounding. Had an almost paper thin crumbling sound as it went from open to close. The diaphram has a very small diameter about a little over one inch, where as the United electric one is about 2.5 to 3 inches in diameter and almost 1mm thickness. It was securely mount with six screws all around the diaphram which appears to be leakproof when it breaks, although I don't really know that.
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With the larger diameter diaphragm the material can be thicker. When working with low sensitivities, inches of Water Column the diaphragm has to be fairly agile. I would be surprised if there is a second seal on the switch side of the diaphragm.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Look at the quality of this united electric piece vs the Sid Harvey
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Well worth it for $360 bucks vs $700 for the sid harvey
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That's about $2100 worth of plastic right there!
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Then don't shop at Sids!
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Even though those plastic microswitches are rated for the motor, I wouldn't trust them turning on/off repeatedly. The United Electric one is super heavy-duty industrial type. I think we all can see the engineering that went into that switch. I believe there's even a little weep hole by the 12 o'clock fastening nut.
Also looking at the United Electric switch, I would not be surprised if there is a gasket there by the little metal rod which activates the switch. I think it is probably leak proof, or at least very little diesel will get thru there.
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The problem with a second layer of sealing things up like the switch actuator shaft is drag resistance. With working at such low pressures any extra resistance to parts that have to move can make the device unreliable or erratic with time as parts age. The diaphragm is always against the pressure, even so, if it stiffens up with age or leaks the calibration would change.
The quality does look much better, so with any luck you will get a good service life out of it. It has microswitches and they fail, but probably could be replaced with minor disassembly.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Makes sense! Thanks for the input.
0
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