| Author |
Message |
David (Davidinwilmnc)
Registered Member
Username: Davidinwilmnc
Post Number: 189
Registered: 7-2005
Posted From: 75.180.200.138
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 21, 2007 - 12:50 pm: | |
My coach / OTR heater control valve isn't working on my MC-8. The green 'heat' dash light cycles on and off and the thermostat seems to control everything properly. I can hear the heater control valve clicking as 26.x volts are applied to it in response to the thermostat. Both the inlet and outlet ports are hot, which indicates that the valve isn't closing. Do people repair these or is it better to just replace them? With all the converters that remove the OTR heat and A/C, I'm sure that there are a few out there headed to the scrap pile! If anybody has one that works that they're not using, I'd love to hear about it and work something out. Also, the manual indicates something about 15 volts max being sent to this coil, but I'm reading full coach DC voltage here (and the valve is labeled '24 Volts'). Am I missing something... perhaps the 15 volts is from the sensor to the controller? It doesn't look like this will be much trouble to replace, as I've got to drain the water and add proper coolant anyway, but it'd be nice to have heat that's controllable some other way than from the rear shut-off valve! Thanks!
David |
Buswarrior (Buswarrior)
Registered Member
Username: Buswarrior
Post Number: 1090
Registered: 12-2000
Posted From: 76.66.19.177
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 21, 2007 - 10:11 pm: | |
Hello David.
Does it get too hot in the coach?
That valve doesn't just stay closed, it cycles, on its own, and at times that don't necessarily make sence.... rendering the heat on both sides of the valve a somewhat unreliable trouble shooting technique.
happy coaching!
buswarrior |
David (Davidinwilmnc)
Registered Member
Username: Davidinwilmnc
Post Number: 190
Registered: 7-2005
Posted From: 75.180.200.138
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 21, 2007 - 11:03 pm: | |
Yes, it's WAY too hot in the bus. Even with the temp set to the coolest setting, the heater core is getting hot water (as long as the rear shutoff valves are open). The valve is receiving power when the green light is off, indicating the system isn't calling for heat. |
John MC9 (John_mc9)
Registered Member
Username: John_mc9
Post Number: 535
Registered: 7-2006
Posted From: 66.217.101.123
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 21, 2007 - 11:45 pm: | |
Re:
"The green 'heat' dash light cycles on and off and
the thermostat seems to control everything properly. I can
hear the heater control valve clicking as 26.x volts are
applied to it in response to the thermostat. Both the inlet
and outlet ports are hot, which indicates that the valve
isn't closing."
As buswarrior said, the valve can open and shut so frequently,
that both sides can remain hot... It's just not a great troubleshooting
tool!
More often than not, the heat sensor gets stripped out during
the removal of the ductwork. Without that sensor in the direct
area of heat flow, it can get awfully hot, since it's not seeing
the same temperature that you happen to be feeling. Oh sure,
the system cycles fine, things click, and heat's produced....
Unfortunately, you don't have a way to control it....
You can "test" that valve by hot-wiring it to stay closed.
If you find that valve is working OK, you might want to consider
using a home type electronic thermostat to control the power
to that valve.....(?)
Lotsa' luck. |
David (Davidinwilmnc)
Registered Member
Username: Davidinwilmnc
Post Number: 191
Registered: 7-2005
Posted From: 152.20.216.103
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 22, 2007 - 9:38 am: | |
Hi John,
Yep, the valve clicks when power is connected to it (bypassing the control system), but it still allows coolant to flow, which it shouldn't do. I did relocate the sensor, as I'm using part of the return tunnel for the supply side of the system. I guess I just need to find a new valve. Thanks!
David |
John MC9 (John_mc9)
Registered Member
Username: John_mc9
Post Number: 536
Registered: 7-2006
Posted From: 66.217.107.200
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 22, 2007 - 11:37 am: | |
I might be mistaken, but doesn't that valve remain in the
closed position until it receives power? I thought it was due
to the need to keep the engine coolant from circulating until
the engine's up to temperature....
But yeah, changing that valve would cure the questioning of it...
OH, and.... please don't forget to post the final remedy to this
same thread? It'd be archived as a complete question and answer
for all us dummies to read in the future...
Stay sane. |
David (Davidinwilmnc)
Registered Member
Username: Davidinwilmnc
Post Number: 192
Registered: 7-2005
Posted From: 152.20.216.103
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 22, 2007 - 12:38 pm: | |
John,
The valve stays open (on) with no power applied. In other words, if the valve fails, it 'defaults' to on. I would assume that this is so there is heat to the coach in the event of a failure, but it has to be regulated by the hand valves in the back. The manual states that the valve is closed when power is applied to it. I think the final remedy is going to be replace / repair the valve. I haven't found any info on repairing it, but I haven't called Luke either! I'm hoping to find a working used one.
David |
Buswarrior (Buswarrior)
Registered Member
Username: Buswarrior
Post Number: 1091
Registered: 12-2000
Posted From: 76.68.121.110
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 22, 2007 - 6:04 pm: | |
Hello.
Sounds like the valve is bad.
Yes, they are normally open, powered shut.
Thanks for clarifying!
happy coaching!
buswarrior |
David (Davidinwilmnc)
Registered Member
Username: Davidinwilmnc
Post Number: 193
Registered: 7-2005
Posted From: 75.180.200.138
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 22, 2007 - 9:16 pm: | |
So, anybody got a spare they don't want or need? |