What's this? (blower found in bay)

Topic: What's this? (blower found in bay) (Read 934 times) previous topic - next topic

What's this? (blower found in bay)

June 10, 2016, 06:24:54 pm

I have 2007 Nimbus 336 Foretravel. I heard something running and traced it to the compartment where the inverter is located along with the hydraulics. Here are pictures of a thermostat and a fan. What setting should the thermostat be set and what is the function of the fan?

[edited topic title to be more descriptive - Michelle]

Re: What's this?

Reply #1 – June 10, 2016, 06:40:47 pm

It is a bay heater. Set the thermostat to 40° or so. Looks like it is at 80°.

Re: What's this?

Reply #2 – June 10, 2016, 06:54:54 pm

Roger may be correct, Ive only looked at a handful of older FTs, but Ive been RVing for a long time, Looks like just a ventilation fan, to remove heat, to me? could be a heater, but the fan is running into a plain hose.. I dont see any way for it to make heat. The thermostat doesnt even go low enough for your average freeze protection settings.

Also dont know why the hydraulic/electrical bay would need to be heated.. especially since the inverter generates a lot of heat.

Re: What's this?

Reply #3 – June 10, 2016, 06:55:13 pm

If I set it on 40 it keeps running. If I set it on 85 it cuts off.....

Re: What's this?

Reply #4 – June 10, 2016, 07:18:19 pm

I would leave on 80 as it looks like it's there to keep that area from getting to warm.

Re: What's this?

Reply #5 – June 10, 2016, 07:22:50 pm

The squirrel cage fan in to remove heat from the compartment. Gets quite warm in there with all the electronics. Looks like someone added the adjustable thermostat. The gray box attached to the fan housing has a preset thermostat in it. Possable the previous owner installed the other one

Re: What's this? (blower found in bay)

Reply #6 – June 10, 2016, 07:41:30 pm

What Richard said. In that bay it's ventilation due to the inverter and other electronics being there. It is not a bay heater - that would be in the wet/plumbing/tank bays.

Now, the thermostat is not something I've seen before and operating the way it does, it definitely seems backwards. Perhaps a DIY attempt by a previous owner that wasn't done correctly?

Re: What's this? (blower found in bay)

Reply #7 – June 10, 2016, 07:50:30 pm

Possibly an added thermostat hay wired by the P.O. That should be a preset temperature cooling fan that turncoat on above the preset. It appears to be turning off above 85 when the knob is set to 85. This is how a heater thermostat would work.

Can you feel the outlet hose? Does it get warm or stay cool? It doesn't look like a heater. And where does it lead? Is he taking waste heat to some other bay?

I can think of no reason to ever heat this compartment?

Re: What's this? (blower found in bay)

Reply #8 – June 10, 2016, 08:36:12 pm

There are two types of thermostats. One thermostat, switch, closes on temperature rise, this is a cooling thermostat. Another type of thermostat closes on temperature drop, this is a heating thermostat.

Re: What's this? (blower found in bay)

Reply #9 – June 10, 2016, 08:37:22 pm

Second look ... I agree, most likely for exhausting heat from the bay. Interesting thermostat add-on.

Tom, in MN when it is -30° every bay needs heat.

Re: What's this? (blower found in bay)

Reply #10 – June 10, 2016, 08:58:26 pm

Quote from: Roger & Susan in Home2 – June 10, 2016, 08:37:22 pm

Second look ... I agree, most likely for exhausting heat from the bay. Interesting thermostat add-on.

Tom, in MN when it is -30° every bay needs heat.

It looks to be exhausting heat from the bay, but that is acting like a heat thermostat.

Even in MN, waste heat from the electronics in that bay precludes any need for a heater. Mine only has a cooling fan for the electronics.

Re: What's this? (blower found in bay)

Reply #11 – June 10, 2016, 09:11:07 pm

Quote from: Beerslayer_24 – June 10, 2016, 08:36:12 pm

There are two types of thermostats. One thermostat, switch, closes on temperature rise, this is a cooling thermostat. Another type of thermostat closes on temperature drop, this is a heating thermostat.

Quote from: dixie flyer – June 10, 2016, 06:55:13 pm

If I set it on 40 it keeps running. If I set it on 85 it cuts off.....

These thermostats are brain-teasers. To state Bob's explanation another way, when you turn "down" a cooling thermostat, it will turn on to attempt to reach the colder temperature requested. This is what Dixie Flyer said was happening. In summer temperatures the 40 degrees will never be reached without some type of additional cooling, so the fan would run continuously.

When you turn "up" a cooling thermostat, it will turn off when the temperature matches the ambient temperature (85 degrees in this case) - because cooling is no longer being requested. Again as Dixie Flyer stated was happening. When set at 85 degrees and fan off, if the temperature would rise above 85 degrees, the fan would turn on, as stated by Bob, to try to reduce the temperature back to 85 degrees, and then shut off again.

This is the way the kitchen Fantastic vent thermostat works, this is also a "cooling" thermostat.

Re: What's this? (blower found in bay)

Reply #12 – June 10, 2016, 09:24:25 pm

I agree with Tom, the blower is exhausting the hot air at the top of the electronics bay.

Not knowing what the ambient temperature is, a cooling thermostat will energize when the ambient temperature rises above the set point. It may seem counter-intuitive, but lowering the set point on a cooling thermostat once it is energized has no effect. One would have to raise the set point to above ambient to open the contacts, on a cooling thermostat.

Some thermostats include both functions, that is another discussion.

Bob

Ah, I see Peter has posted as well, thanks.

Re: What's this? (blower found in bay)

Reply #13 – June 10, 2016, 10:01:30 pm

This is an exhaust fan. Leave it set for 80 degrees. Also, up high on the back wall where the transfer box is mounted, you will notice the wall has openings to the other side cabinet. Be sure these areas are not blocked with items from the other side. The exhaust fan will draw air in from those cabinets. The unit vents to the underside of the coach. There is a screen on the vent below to keep bugs and rodents out. I have found when in areas that the outside temp reaches near 100 degrees, to open the bay door an inch. I have made a tool to place in the opening to allow the door to remain open an inch. The inverter makes a lot of heat and it needs to be vented.
Bob

Re: What's this? (blower found in bay)

Reply #14 – June 10, 2016, 10:08:15 pm

Quote from: bobnkathy – June 10, 2016, 10:01:30 pm

This is an exhaust fan. Leave it set for 80 degrees.

The inverter makes a lot of heat and it needs to be vented.
Bob

Bob,

Doesn't it seem to you that the installed thermostat is an incorrect one - as Peter and the other Bob (Beerslayer) have mentioned, if it's to exhaust heat as we all believe, the fan should run whenever the temperature is above the setpoint and shut off below it Richard (Dixie Flyer) is reporting it's shutting off when he raises the setpoint, which is not what a cooling fan's thermostat should do.

Re: What's this? (blower found in bay)

Reply #15 – June 10, 2016, 10:31:08 pm

This is where it gets confusing...when you raise a cooling thermostat above ambient temp it shuts off - as noted. When you raise a heating thermostat above ambient temp it turns on...

Re: What's this? (blower found in bay

Reply #16 – June 10, 2016, 11:17:03 pm

I suspect the original owner incorrectly added a heating thermostat. I'd bypass it so the OEM thermostat and fan can work as intended.

Re: What's this? (blower found in bay)

Reply #17 – June 10, 2016, 11:23:22 pm

Quote from: Tom Lang – June 10, 2016, 11:17:03 pm

I suspect the original owner incorrectly added a heating thermostat. I'd bypass it so the OEM thermostat and fan can work as intended.

But, Tom, I respectfully beg to differ, it is working like a cooling thermostat should work...

Re: What's this? (blower found in bay)

Reply #18 – June 10, 2016, 11:50:35 pm

It appears that the temperature in the bay is less than 85 degrees.

Re: What's this? (blower found in bay)

Reply #19 – June 11, 2016, 12:02:57 am

Quote from: Tom Lang – June 10, 2016, 11:17:03 pm

I suspect the original owner incorrectly added a heating thermostat. I'd bypass it so the OEM thermostat and fan can work as intended.

To set the record straight, what you are seeing here is original to the coach. I have the same model, two build numbers before this coach. We are original owners and have had this thermostat since the day we purchased the coach from FOT. Thanks
Bob

Re: What's this? (blower found in bay)

Reply #20 – June 11, 2016, 12:09:05 am

If I set it on 40 it keeps running. If I set it on 85 it cuts off.....

That sounds like a heating thermostat to me. Perhaps the wrong one was installed.

Re: What's this? (blower found in bay)

Reply #21 – June 11, 2016, 12:19:41 am

Quote from: dixie flyer – June 10, 2016, 06:55:13 pm

If I set it on 40 it keeps running. If I set it on 85 it cuts off.....

Are you sure the fan is going off when you lower it? If so, then the wiring is reversed. Need to wire to low side instead of high side connectors.
We had this when we first purchased our coach from the factory. That was only one problem, we had fan blades mounted backwards, two belt engines installed with the grove side up, the hoses going to air compressor reversed, the ECM not programmed to the transmission, and much more. I was told when the coach was started to be built in mid 2006 and they had some disgruntle workers and some coaches suffered their anger. Possibly starting to find some of the same issues. Are you finding the coach overheating (running at temps over 205) at times especially in warm weather or making a noise like ball bearings rolling around in the engine area when idling?
Bob

Re: What's this? (blower found in bay)

Reply #22 – June 11, 2016, 12:28:29 am

Quote from: bobnkathy – June 11, 2016, 12:19:41 am

Are you sure the fan is going off when you lower it? If so, then the wiring is reversed. Need to wire to low side instead of high side connectors.
We had this when we first purchased our coach from the factory. That was only one problem, we had fan blades mounted backwards, two belt engines installed with the grove side up, the hoses going to air compressor reversed, the ECM not programmed to the transmission, and much more. I was told when the coach was started to be built in mid 2006 and they had some disgruntle workers and some coaches suffered their anger. Possibly starting to find some of the same issues? Are you finding the coach engine overheating (running at temps over 205) at times especially in warm weather or making a noise like ball bearings rolling around in the engine area when idling?
Bob

Re: What's this? (blower found in bay)

Reply #23 – June 11, 2016, 12:55:17 am

Quote from: Michelle – June 10, 2016, 10:08:15 pm

Bob,

Doesn't it seem to you that the installed thermostat is an incorrect one - as Peter and the other Bob (Beerslayer) have mentioned, if it's to exhaust heat as we all believe, the fan should run whenever the temperature is above the setpoint and shut off below it Richard (Dixie Flyer) is reporting it's shutting off when he raises the setpoint, which is not what a cooling fan's thermostat should do.

This is a vent fan to pull heat out. Exact same setup on my '07. Set the T-Stat to 80.

Re: What's this? (blower found in bay)

Reply #24 – June 11, 2016, 12:58:25 am

Quote from: Tom Lang – June 11, 2016, 12:09:05 am

If I set it on 40 it keeps running. If I set it on 85 it cuts off.....

That sounds like a heating thermostat to me. Perhaps the wrong one was installed.

If it is set on 40 it is trying to get the bay to 40 which would be making the fan run. When set on 85 it turns off as that is probably the temp in the bay. Same as turning air conditioning thermostat to 60 and air comes on until it reaches the setting.

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