Do You Use 420E and Heated Hose?

Geocom · Post by **Geocom** » Thu Feb 09, 2006 6:38 am

Recently, I've been having a problem with my Puritan Bennett 420E abruptly shutting off, jolting me awake, leaving me gasping for air. When I would inhale deeply, it would trigger my 420E to shut down for the duration of a couple breaths. This was happening several times a night--and needless to say, is a bad thing.

After posting my problem on this site, Rested Gal mentioned that she had heard anecdotally that others have had the same problem when using the 420E and the heated hose that has the piggyback connector.

This prompted me to look deeper into the possibility that the heated hose with the new piggyback connector was the culprit. I did an experiment with my heated hose plugged in, and with the heated hose unplugged. With the hose plugged in, the machine would stop when I inhaled deeply. With the hose unplugged, the problem went away. I repeated this several times, getting the same result each time.

Last night, with the heated hose unplugged, the problem went away completely for the entire evening.

Since this problem only started once it got cold here in Virginia, I suspect static electricity may be the culprit; but that's only an intuitive hunch.

We all know that Don at Sleep Zone in Australia provides a terrific product that, for many of us, has made our therapy much more tolerable. I never miss an opportunity to tell people how much I love my heated hose. Let's hope Don can determine why this is happening, and provide a good solution to this problem.

If you have the same configuration, and experience this problem, I'd suggest you send Don an email at don.fischer@optusnet.com.au

Guest · Post by **Guest** » Thu Feb 09, 2006 8:08 am

I had that problem, sent him an emial, he instructed I bend the center pin off center, I didn't help. I wrote again, he replaced my hose with another piggyback, which did the same thing!! I solved the problem by using the radio shack adapter, and not routing it thru my 420E.
In his letter to me, he stated he had never had this problem reported "B4"
So wasn't I surprised to see a post at least 6 weeks later,that cut and pasted a letter from Donl..stating he had never had this problem reported
"B4". HUH!! He was also instructing that cpaper to bend the center pin for better contact. Hey, I sleep at a high pressure, and that adapter just won't power both the hose and machine consistently!!
It will cause the 420E to loose power intermittently!! A little jiggle or deep breath or power increse can trigger it. He DOES know it is a problem...has known for at least a year!!
The heated hose is a good product, the piggyback was a nice idea..just didn't work.

WAFlowers · Post by **WAFlowers** » Thu Feb 09, 2006 1:12 pm

The US power supply for the 420E is marginal (amperage is low) to run both the machine and a piggyback hose. I don't remember the numbers (amp ratings for 420E and heated hose) but search around this forum and you'll see them in some posts.

It is working for me but I'm at relatively low pressures (7.0-9.0 APAP).

I'm guessing, but I suspect that at higher pressures the 420E would draw more current. Plus, when you take a breath the unit works harder (spins its turbine faster) to maintain the pressure as you are drawing down the air already pressurized in the hose and mask. Pulling too much current out of a wall wart (one of those transformer plugs) will cause it to heat up and for the delivered voltage to drop. If the voltage drops too far, I'd expect the CPU in the unit to crash.

Going to a seperate power supply for the heated hose or one bigger power supply for both would solve this problem, if that is the problem.

snork1 · Post by **snork1** » Thu Feb 09, 2006 5:08 pm

The petite power supply for the 420E is 12V 2 amps.
The HUGE 12v power supply from Radio Shuck is only 1amp, oddly enough.

I don't have the numbers for the current draw for the 420E and heated hose, but its apparently somewhere slightly above 2 Amps at higher pressures. Its a bummer our Aussie friends didn't anticipate and check this out. That is more than a little sloppy on their engineering work.

I would think there MUST be a 2-3 amp 12VDC power supply out there somewhere that would be worldwide voltage, compatible with this system, and be a size smaller than the two power supplies combined and maybe somewhere between the size of the 420E stock supply and the Radio Shack monster. (why IS that Radio Shuck one so BIG????)

ozij · Post by **ozij** » Thu Feb 09, 2006 8:57 pm

Same for me, with the Eurpean version of the power supply.

PB sells different power supplies on different continents, and the original Australian one seems to have been strong enough to handle piggy backing.

Don knows of the problem with European one from me since the end of August 2005.

viewtopic.php?p=35675#35675

Note nev's important info on that thread.

Guest doesn't give date in his/her letter - it would have been nice for her/him to be more specific.

I am reposting that thread under its own heading.

O.

Firehorse · Post by **Firehorse** » Thu Feb 09, 2006 10:05 pm

A reminder for anyone tempted to buy one large 3 amp power supply to safely run both their 420e and heated hose. The 420e comes equipped from PB/Tyco with what is called a "switched" or "switching" power supply. That is a very clean, digitally regulated type of power supply.

Many people here have purchased a Radio Shack transformer to run their heated hose. That kind of power supply is actually a lesser grade "linear regulated" power supply. It is just fine for running a heated hose, but even a 3 amp or larger "linear regulated" power supply should NOT be used to power the 420e (with or without heated hose).

So if you plan to buy one large power supply to run both heated hose and the 420e, then you must meet the 420e's power requirements. That means you should buy a 3 amp or better "switched" or "switching" power supply---and not the 'linear regulated" type.

In summary:
=========

1) The heated hose can use either a lesser grade "linear regulated" type power supply or the better grade "switched" or "switching" power supply

2) The 420e cannot reliably use the cheaper "linear regulated" power supply. Its microprocessor-based circuitry requires the superior "switched" or "switching" type power supply to run reliably.

Firehorse · Post by **Firehorse** » Thu Feb 09, 2006 10:25 pm

That is a very clean, digitally regulated type of power supply.

Oops... It's not digitally regulated. It's switching-circuit regulated and it's typically employed in digital/microprocessor-based circuitry that requires cleaner, better regulated power.

snork1 · Post by **snork1** » Fri Feb 10, 2006 12:20 am

Firehorse wrote:
That is a very clean, digitally regulated type of power supply.
Oops... It's not digitally regulated. It's switching-circuit regulated and it's typically employed in digital/microprocessor-based circuitry that requires cleaner, better regulated power.

Nev · Post by **Nev** » Fri Feb 10, 2006 12:45 am

As noted in previous posts, I can run a 420E with a "piggy-backed" heated hose no problems with a Powertec MP3240 power supply rated at 100 to 240V input and 12V 4A output that came with my 420E purchased in Australia. That power supply would work quite happily in the US too. It's made in China so there's no reason why it shouldn't be available in the US. Maybe you guys should try asking for it when you buy a 420E?

WillSucceed · Post by **WillSucceed** » Fri Feb 10, 2006 8:57 am

2) The 420e cannot reliably use the cheaper "linear regulated" power supply. Its microprocessor-based circuitry requires the superior "switched" or "switching" type power supply to run reliably

OK, Firehorse, now I'm confused (even moreso than usual) and need some clarification.

I don't have a heated hose, but I do have my 420E plugged into a UPS. I know that the UPS has adequate wattage to run the 420E and the heated humidifier but, it is not producing a pure/true sine wave. It is producing a modified sine wave. I've been using this for many months and have not noticed any problem with my 420E.

Should I be concerned about this? I know that the juice coming from the wall outlet is a pure sine wave. Will the modified sine wave coming from the UPS damage my 420E?

Firehorse · Post by **Firehorse** » Fri Feb 10, 2006 9:08 am

Any after-market high quality "switched" or "switching" 12 volt power supply rated at 3 amps or better can be used to piggyback the 420e and the heated hose---as long as the connector plug happens to physically fit with the correct polarity.

For the sake of the 420e you must avoid using linear regulated power supplies (they usually employ large transformers with copper windings and one or more linear voltage regulator ICs). Worse yet, are the transformers or wall warts that use transformers and don't even bother to regulate the voltage at all. They simply drop or step the voltage down with transformer windings, then change the voltage A.C. to D.C. using simple rectifier diodes. As unreliable as the linear regulated power supplies would be for the 420e, these latter totally unregulated transformers would be even worse. It is the transformers that make both of these power supplies or wall warts so large. They are not bad power supplies for their correct applications---such as a heated hose.

The Aussie analogue heated hose is much less picky about its power supply than the microprocessor-based 420e, which is why that heated hose would be more than happy to piggy-back onto a "switched" or "switching" type power supply along with the 420e (as long as there was enough current capacity for both devices). I bet someone on the message boards will eventually find and post a third-party link to a nice cost-effective 3 or 4 amp switched power supply that the 420e and heated hose can happily share!

Now I just need to figure out why my 420e very rarely glitches out when I take a sudden and deep breath. I don't piggy back anything on mine.

Firehorse · Post by **Firehorse** » Fri Feb 10, 2006 9:41 am

WillSucceed wrote:OK, Firehorse, now I'm confused (even moreso than usual) and need some clarification.

I don't have a heated hose, but I do have my 420E plugged into a UPS. I know that the UPS has adequate wattage to run the 420E and the heated humidifier but, it is not producing a pure/true sine wave. It is producing a modified sine wave. I've been using this for many months and have not noticed any problem with my 420E.

Should I be concerned about this? I know that the juice coming from the wall outlet is a pure sine wave. Will the modified sine wave coming from the UPS damage my 420E?

Everything is A-okay with your setup, WillSuceed!

Think of the 420e's "wall wart" as the true "power supply" in your configuration and the UPS that you use as a "substitute source" of A.C. when the power company's A.C. is unavailable. The confusion is that the term "power supply" is used by manufacturers and the general public for two pieces of equipment that do not server the same purpose.

The 420e's "wall wart" serves the purpose of making your 110-120 volts a.c. wall voltage a good useable 12 volts D.C. that the 420e circuitry needs. The UPS, on the other hand, serves the purpose of delivering 110-120 volts A.C. when there is none coming out of your wall (in addition to wave filtering that A.C. when it is available from the public utility company). Yet these two functionally different pieces of equipment are both referred to as "power supplies".

The term "modified sine wave" in relation to a UPS means that when the UPS does happen to source A.C. (during a black out for instance) that A.C. waveform will be squared off or stepped---not a true sinusoidal waveform as you would get from the power company. The 420e and just about all digital or microprocessor-based circuitry is very happy to receive that squared off or stepped A.C. voltage versus the sinusoidal voltage normally sourced from the electric utility company.

By contrast that squared off or stepped A.C. voltage waveform (sometimes called a "modified sine wave") can be a problem for certain heated humidifiers. the problem is that the squared off or stepped A.C. voltage waveform contains vertical edges in each voltage cycle. And those vertical edges in turn contain way more energy harmonics than any sinusoidal waveform---enough energy harmonics to gradually deteriorate the triac I.C.'s that were employed in some of the older CPAP heated humidifiers. To my knowledge, most CPAP heated humidifiers sold today are compatible with UPS power sources that yield squared off or "modified sine waves".

WillSucceed · Post by **WillSucceed** » Fri Feb 10, 2006 10:08 am

Thanks, Firehorse, for the reply. I appreciate the help.

Firehorse · Post by **Firehorse** » Fri Feb 10, 2006 10:38 am

Now I just need to figure out why my 420e very rarely glitches out when I take a sudden and deep breath. I don't piggy back anything on mine.

My best guess is that the same thing is happening with my 420e that is happening with the piggy-backed 420e machines. Here's what I think is happening:

1) Very deep, very sudden inhalation causes a sudden pressure drop as measured by the 420e,

2) The 420e suddenly increases impeller rotation in an attempt to restore target static air pressure,

3) That sudden dramatic "on-demand" impeller rotation in turn causes an instantaneous surge in current demand,

4) That sudden increase in current demand cannot cleanly and reliably be sourced by the 420e's own 2 amp power supply---especially in the case of a heated hose being piggy-backed onto that power supply

5) The 420e's microprocessor crashes (exactly as WAFlowers stated earlier) for lack of stable power during that instantaeous "deep-breath-originated" current draw.

The 420e's 2 amp power supply is more than adequate for stable breathing or "steady state" circumstances. Depending on certain factors (pressure already being delivered, how deep-and-sudden your inspiration happens to drop that pressure, and whether anything is piggybacked onto the 42oe's power supply) your 420e power supply may or may not have an adequate margin of instantaneous current-delivering capacity. The 420e will usually have an adequate margin of instantaneous current-delivering capacity to avoid a "deep-breath-driven" microprocessor crash.

That's my best guess and I'm sticking to it! Forget that hyperventilation story that other Firehorse wondered about. That poster should have been nicknamed Crazy horse, not Firehorse.

Guest · Post by **Guest** » Fri Feb 10, 2006 11:24 am

Ozij,
I am from the united states.
I originally wrote to Don Fisher about the piggyback problem on July 10, 2005...He replied on July 11, the he had never had the problem B4

He did send a replacement hose, which I advised him did the same thing,

Mask	Humidifier

Do You Use 420E and Heated Hose?

Do You Use 420E and Heated Hose?

Crucial Power Supply Differences

420E and Heated Hose