IR H15T4 Help

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benha

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Messages
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Location
California
# of dives
200 - 499
Hello!

I have an H15T4 that I acquired - believe it or not - from a junk yard. The machine is in very nice shape, but had the misfortune to be installed in a fire truck that blew its motor and I guess they just scrapped the whole vehicle. Go figure...

Anyway, I took it home and cleaned it up a bit, and have it hooked powered up and proved it's not seized up or anything. Unfortunately, however, the plumbing seems to have been configured in a manner that's not what I would expect looking at the documents, and the docs aren't specific enough for me to be able to figure out what's correct.

Does anyone have one of these and could send me some photos?

The particular area of interest here is the unloader circuit. If I understand correctly the fitting front and center on the block, aligned with the crank, should be plumbed into the auto-drain system.

In mine, it's capped off, and it looks like the auto-drain is actually fed through a line coming from the 2nd stage outlet, routed through a solenoid valve (presumably for triggering auto drains during operation).

If there's an expert out there that can help me get things back in fighting trim I'd be very appreciative.

-Ben
 
Fair enough. Here we go.

This is the front of the compressor block. By my understanding, that capped off fitting should be connected to the auto drain valve system. When the compressor is running it's pressurized and keeps everything sealed up. When the compressor shuts down the pressure loss cascades through the drain system causing all the stages to depressurize. So the fact that it's plugged up is confusing.



This is the control inlet side of the auto drain block. The red-hat is on top of a 3-way solenoid valve. The side that feeds the auto-drain is connected either to that hard line running off to the right, or to a vent line depending on the state of the solenoid.




The solenoid valve is connected to a tube coming off the second stage moisture separator. It's a little hard to tell but in this photo there are two tubes going down toward the ground. The one that's to the right of and in front of the other is the tube that feeds to auto drain.

So it looks like they're controlling the auto-drain with the second stage instead of the first, which is super weird because the centrifugal control is on the first stage.

I'm actually having a minor epiphany as I write this. It could be that the solenoid is NO instead of NC. In that case and that it's supposed to be energized when the compressor is in operation (presumably via a timer switch that unloaded it on an interval). Then turning off the compressor would de-energize the solenoid and substitute for the mechanical unloader valve.

I'll have to test that...
 
the first picture looks like the oil breather tube. I assume it was plugged since it was on a truck instead of stationary as oil can splash out of it. You'd have to find the repair manual to check where it's supposed to go.

Solenoid should be NO for the drain. It is usually a pilot assist system where the solenoid is a low pressure solenoid from the first stage and it uses the first stage pressure to keep the other drains closed. On the timer or shutdown it opens and the whole system purges
 
the first picture looks like the oil breather tube. I assume it was plugged since it was on a truck instead of stationary as oil can splash out of it. You'd have to find the repair manual to check where it's supposed to go.

Solenoid should be NO for the drain. It is usually a pilot assist system where the solenoid is a low pressure solenoid from the first stage and it uses the first stage pressure to keep the other drains closed. On the timer or shutdown it opens and the whole system purges


Looks like a breather, but it's not. Or at least not according to the parts manual. But regardless, if that solenoid is NO then that's probably my answer. I haven't hooked it up to anything since I wasn't concerned about auto drains at this stage in commissioning the unit. So if I need to energize it to close the pilot circuit then that'll probably be the issue.

Still not at all clear why they'd bypass the mechanical unloader AND move everything from the first stage to the second, but it looks like that's what's happening.


Screen Shot 2020-08-10 at 11.57.15 AM.png
 
https://www.shearwater.com/products/teric/

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