No air

Topic: No air (Read 1026 times) previous topic - next topic

No air

January 03, 2022, 10:14:59 pm

Left for Whistler last night. First thing I got a code saying intake temperature. Then this
morning the air pressure was down to 30 PSI and it wouldn't build up air. Found air coming
out the governor exhaust so I put a new governor on and the same thing happening. If I can't
figure out what's wrong I will go and take a electric compressor and feed it in the connection
I have before the drier and bring it home. If anyone has an idea I all ears.

Re: No air

Reply #1 – January 03, 2022, 10:53:23 pm

Problem #1: Can't help with the intake temp code.

Problem #2: Governor leaking air out the exhaust port & can't build air pressure in wet tank.

I am thinking the problem is in the line that goes from D2 to air dryer, or rather in the air dryer where that line connects. Trying to figure out what malfunction in dryer control valves would produce your symptoms.

Something stuck in the air dryer? Purge valve frozen or stuck? Heater not working? Getting kinda late at night for clear thinking. Sorry.

Google search turned up links below:

D-2 Ports

https://talk.newagtalk.com/forums/thread-view.asp?tid=447428&DisplayType=flat

Air Dryer is Purging Air through Unloader Port (Line to Governor) - School...

Re: No air

Reply #2 – January 03, 2022, 10:59:07 pm

I'm heading back up tonight and right now I just want to get it home. No skiing this
week. To bad as there is a lot of new snow.

Re: No air

Reply #3 – January 03, 2022, 11:32:33 pm

Does sound like purge valve malfunction. I replaced with rebuilt and was planning on rebuilding next cycle. Seems never ending. I do carry a dryer bypass fittings for emergency. Was there a code associated with inlet temperature, high?.

Re: No air

Reply #4 – January 03, 2022, 11:44:58 pm

Might look at check valve. Freeze shut? From dryer line to tank . Fire it up, and pull drain cords, check for flow.?

Re: No air

Reply #5 – January 03, 2022, 11:52:54 pm

Thought about it some more while taking a shower.

The line that goes from the D2 to air dryer should only be pressurized when the dryer purges and the air compressor cuts out. At cut-out pressure, the D2 sends a pressure signal out the unloader port to the air compressor and down that air line to the air dryer.

If something (?) in/on the air dryer sticks and/or malfunctions, you could get continuous reverse air flow from the dryer to the D2. That air may exit the exhaust port on the D2. If so, then you can't build pressure in the wet tank because your air pressure is going out the D2 exhaust port. The exhaust port on the D2 will not close until you build pressure in the wet tank. Catch 22.

If you have a 1/8" pipe thread plug, you could try temporarily plugging the exhaust port in the D2. If this allows your air pressure to build to the normal cut-out pressure, then you have found the source of the leak.

Unfortunately, you may have to bypass the dryer (or replace/rebuild it) to get back on the road.

Anyway, that's all I can come up with, FWIW.

Good luck.

Re: No air

Reply #6 – January 04, 2022, 09:12:12 am

Your in Canada what is the temperature outside ? a line or governor or valve is frozen take the line off the compressor ,put a bit of methyl hydrate In it or take a heat gun around the governor and line it just takes a bit of condensation in the line to freeze it Specially a valve , this mostly happens when it's cold and damp outside make sure your air dryer is working properly the air dryer takes the moisture out of the air. That's why we have to service the air dryer there is a filter on it it's supposed to be serviced every two years this is a common problem with air brakes in the winter for trucks a lot of truckers carry a bottle with them .
CAUTION use a small amount of methyl hydrate it is very hard on the valves . This is why it's very important to have a good air dryer and drain all air tanks we have three of them in winter months especially in freezing conditions.in the second picture you can is the filter it is a screw on filter black

Re: No air

Reply #7 – January 04, 2022, 09:32:04 am

Quote from: Chuck & Jeannie – January 03, 2022, 11:52:54 pm

Unfortunately, you may have to bypass the dryer (or replace/rebuild it) to get back on the road.

If you suspect the dryer purge valve is malfunctioning, you may be able to replace just the valve. I don't know what type dryer you have. On my coach with AD-9 dryer, the purge valve and heater assembly is easily swapped out - just 3 bolts. There are 3 different types, so you need to be sure you get the right one. See .pdf document below:

https://www.napaonline.com/en/p/MBI109686X

Re: No air

Reply #8 – January 04, 2022, 06:31:33 pm

I got it home and it is the Drier. Air is coming out the purge valve. If I can find parts
I would like to service the drier. I took a compressor and pipe and brass fittings up
and I used that to come home. I was lucky that I had the right fittings to do the job.
It worked quite well after I found all the things I needed to plug. I forgot my camera
as I would have taken a picture of me snowed in. There was a foot on the roof. Good
snow tires work. I wouldn't have gotten out without them without a lot of shoveling.

Re: No air

Reply #9 – January 04, 2022, 07:07:22 pm

If it is the purge valve I have a new one for sale that my coach doesn't need. I will sell for 75% of what a new one costs.

Re: No air

Reply #10 – January 05, 2022, 03:39:55 pm

Thanks Chuck but I want to do a complete service or get a rebuilt one. When I had a
Monaco I couldn't find parts locally so I put in another kind that I could get the parts
locally.
Rick thanks for the advice, had that problem with the Monaco and I heated the line with
a heat gun.

Re: No air

Reply #11 – January 05, 2022, 03:52:52 pm

Quote from: oldguy – January 05, 2022, 03:39:55 pm

I want to do a complete service or get a rebuilt one.

I've had good luck finding factory rebuilt dryers at NAPA stores. You got those stores in BC? If they don't have what you need in stock can usually get it next day.

Re: No air

Reply #12 – January 05, 2022, 04:04:54 pm

Yes, I am a STRONG believer in factory (i.e. the factory that made it) Reman air dryer.

NOT, a "replaces" unit which means a Chinese knockoff of dubious quality.

And, not rebuilt by "the lowest bidder".

Re: No air

Reply #13 – January 05, 2022, 04:17:06 pm

Quote from: oldguy – January 05, 2022, 03:39:55 pm

When I had a Monaco I couldn't find parts locally so I put in another kind that I could get the parts
locally.

If you go this route make sure that you get a dryer that is compatible with the Holset compressor you have, this is one place one size fits all won't work.

Mike

Re: No air

Reply #14 – January 05, 2022, 06:45:13 pm

I don't find Napa up here that good. From what I have found so far the model that
I have in my coach is discontinued and I can only get parts or rebuilt ones. Mine is
a Midland N4250. If someone has something else that fits let me know.
Thanks Mike I know about that as the compatibility problem from a post within the
last couple of months.

Re: No air

Reply #15 – January 05, 2022, 07:03:26 pm

I am guessing that the purge valve is just frozen. Some models have a heater, wonder if that is not working or yours does not have one. I am sure you can replace it without replacing the whole thing. Post some pics if you can that will help.

Attached is the haldex replacement that is listed for the N4250.

Do you have any big truck part shops near you? They might be able to get you a new purge valve/heater if it's bad. I am also curious if there is power going to the heater, maybe it's just not getting power?

Re: No air

Reply #16 – January 05, 2022, 07:10:55 pm

oldguy
peter, before we left for yuma I ordered the rebuild kits
for my air dryer from amazon.ca

Re: No air

Reply #17 – January 05, 2022, 07:15:58 pm

Peter I've had good luck get parts from Traction Heavy duty truck parts also Parts For Truck we have in Nova Scotia don't know if there in BC. Fleet Brake truck-trailer parts 902 468 1396 B C Heavy Duty Truck Parts

Re: No air

Reply #18 – January 05, 2022, 08:43:15 pm

I think I may have found the parts I need at CBS parts here. They are a truck parts store.
I took the drier apart this afternoon and the purge valve and it is definitely shot.

Re: No air

Reply #19 – January 14, 2022, 08:01:32 pm

I put the the air drier back in and I couldn't figure out where this valve went so I called
Haldex and couldn't get an answer. Started up the coach and still no air so I called back
to Haldex and this guy had me do a few things and the problem was this valve I couldn't
figure out where it went was shot. It's called the Turb-saver Valve. He said the purge valve
was probably OK. I can tell this guy knows these valves. I have it all back together and
will put the drier back in the coach tomorrow.

Re: No air

Reply #20 – January 15, 2022, 02:25:33 pm

I bought an intake air temperature sensor and the the Silverleaf cleared the fault.
The dryer is back in and everything is working. I now know a lot more about air
dryers now. I was planning on servicing the dryer and now it is rebuilt.

Re: No air

Reply #21 – January 15, 2022, 03:56:04 pm

Quote from: oldguy – January 15, 2022, 02:25:33 pm

I bought an intake air temperature sensor and the the Silverleaf cleared the fault.
The dryer is back in and everything is working. I now know a lot more about air
dryers now. I was planning on servicing the dryer and now it is rebuilt.

So what fixed the leak problem? Intake sensor was affecting air production?

Re: No air

Reply #22 – January 15, 2022, 05:49:31 pm

No I had 2 problems. The intake air box sensor happened first. And the no air
happened the next morning which turned out to be the air dryer and it was a
blown turbo-saver valve. The sensor wasn't a big deal but no air is.

Re: No air

Reply #23 – January 16, 2022, 06:34:37 pm

I was very curious what that part is and did a little research. Found this pdf and quickly learned a lot about the way this system operates!

Air Drier System

Re: No air

Reply #24 – January 16, 2022, 07:37:47 pm

That's a good write up, it would have been handy when I rebuilt my dryer. Got the Coach
ready to load up and I will drive part way to Whistler tonight.

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