1983 MC9 - Ex NJT - Coach heat MIA

[TedCalvert]

I, too feared that one of my supply valves was broken.  But they are brass gate valves, not much to go wrong on them.  One of them turned normally, 5-6 turns from open to close; but the other seemed to take many turns and still didn't feel like it bottomed open.  But upon disassembly, I could find nothing wrong.  If I had to replace it, I would have tried to get an OEM valve and only replace the guts, leaving the body in place.  No soldering.  Anyway, if yours is stuck open that's a good thing.

Rebuild your control valve and see what happens.

HTH

[gumpy]

I, too feared that one of my supply valves was broken.  But they are brass gate valves, not much to go wrong on them.  One of them turned normally, 5-6 turns from open to close; but the other seemed to take many turns and still didn't feel like it bottomed open.  But upon disassembly, I could find nothing wrong.  If I had to replace it, I would have tried to get an OEM valve and only replace the guts, leaving the body in place.  No soldering.  Anyway, if yours is stuck open that's a good thing.

Rebuild your control valve and see what happens.

HTH

What normally happens is the gate corrodes in the slot and sticks. Then, someone tries to force it and breaks the stem that connects from the handle to the gate. The gate
remains in the slot and the handle and stem turn but nothing happens.

[Melbo]

The handle turns and nothing happens --- kind of like the lights are on and no one is home.  BUT to replace the guts you have to have the same brand and vintage valve because nothing else will work.  I have seen stripped threads inside the valve on the handle shaft and I have seen the gate stripped inside.  I have seen them seized in both the open and closed position. You can try to heat them if they are seized BUT unless you drain them the water will keep you from getting much over 200 degrees.

Good luck Phil I hope you get this solved and thanks for your work on this forum.

Melbo

[Gary Hatt - Publisher BCM]

Phil, I think it is time to consider a Kimberly Stove.  Check them out at UnforgettableFireLLC.com or see their ad in our Service Directory.   

Click here UnforgettableFireLLC.com

[ArtGill]

I agree the NJT is a strange animal.  I have a Eagle Model 20NJT.  It is an 12 volt coach, BUT it also had a 24 volt generator just for the fans in the coach heating and cooling. This generator was removed when the coach AC was removed.  I found that the circulation pump for the drivers heat was also 24 volt.  The circulation pump was located under the aisle floor.  I also have a cable controlled valve in the driver's heater supply hose in the top of the spare tire compartment.  My Eagle is newer at 1989.   Not sure if any of this will help.

Art

[plyonsMC9]

Thanks all for the help!  All the responses have been quite helpful.  The current status is basically 'on hold'.  The last steps we tried were to test the relay.  First, swapped relays as Craig suggested.  Still no-go. Specifically, the relay would never activate when the bus was aired up & the heat was turned on or off.  However, in continuing to test, we discovered that the ground was loose to the relay.  It appears that the screws were loose and we could jump it - and in a brief moment of glory - the relay clicked!  However, the joy was short lived as the test probe then hit the wrong surface and with a large spark, the whole test went dark.      Soooo - I've since ordered a new socket for the relay from Luke.  The relay has arrived and we're waiting on better weather.  Currently snowy, rainy, windy, cold.  Taking a week off for the Quartzsite rally.  And at the next warm weather we'll see if putting in the new socket, properly grounding it, will fix the heat issue.   I'll continue to update, and kind regards to all - hope to meet some of you at the rally.

- Phil

[plyonsMC9]

Well, I did meet some of you at Quartzsite and it was a real treat for me.   

For the heater repairs, we've repaired the relay socket (driver side, outside panel).  We've tested the valve in the middle bay by heating the temperature sensor in the middle bay (removed it from the center wiring chase/ airway) with a heat gun on low temp.  Valve functions - or, it is magnetized and we can hear it activating.  Sooo - all systems appear to be operating properly.  One of the two valves is frozen open (supply valve) back from when this all used  to work.  BTW - this is how I know it is stuck open.  This whole system worked flawlessly a couple years' ago.  The valve was always frozen - so it must've been open since I've never been able to move it more than an inch.  Next order is to replace that valve guts w/a used valve.  Luke @ US coach will hopefully be supplying soon.   I been told by Bill they can pull from another MC9.  Will validate Monday. Once the valves are both functioning, we'll shut 'em off & rebuild the valve assembly in the middle bay (thank you Clifford for that suggestion). Possibly something is broken in the valve even though it is activating?  I have the rebuild kit - also from Luke @ US Coach.

I feel like I'll know the entire heater system pretty well after all this is done.   

Kind Regards, Phil

[gumpy]

My money is still on one of the two gate valves in the engine compartment.

BTW, did you try bleeding the heater core to make sure you don't have an air lock in it?

[plyons]

Thanks Craig - yes, we did bleed the heater core up by the driver.  As soon as I loosened the "cap" on the top of the core I had coolant coming out.  Later had DD mechanic do the same (don't always trust myself) and he validated - no air pocket.

We'll know soon enough on those valves.  I'd love this mystery tour to come to an end.   

Kind Regards, Phil

[plyonsMC9]

Yes still working on the gate valves so I can fix the coach heat.   

To replace the gate valve on the driver side of the bus up in the engine compartment, is there an issue w cutting the valve off at the pipes then putting in a new valve with 1 1/4 pipe nipples on either side. Then using heavy hose & hose clamps to attach the valve?  This would be to ease the installation of the valve - much like some of the radiator hoses are attached.  It's in a pretty difficult place to reach.

Thanks!  Phil

[buswarrior]

That will work, but be sure the pipe ends all have a rib for the clamps to bite into...

otherwise there is a danger of one of them sliding off and catastrophic overheat shortly afterwards.

Some mechanical external securement in order that the parts don't slip apart is also an option.

happy coaching!
buswarrior

[plyonsMC9]

Excellent advice -  Thanks buswarrior!!

Kind Regards, Phil

[eagle19952]

Excellent advice -  Thanks buswarrior!!

Kind Regards, Phil

is there room for hose nipples ?

[eagle19952]

[Oonrahnjay]

is there room for hose nipples ?

     I think I've seen those called "hose barbs".  Hose ends nor hose clamps slip off of those.