Found a fix for "No Alde heat" when all fuses are good

db_cooper · January 2022

@Tabulating
Boards are about $300 last time I checked, and the go to answer from Alde when the thermal fuse goes.

I think the problem is thermal fuses degrade and it's hot enough under the benches to slowly degrade the low melting point of the thermal fuse. Instead of a spare board, I carry a jumper (2 alligator clips on a wire) to bridge the fuse in an emergency. Haven't had to use it, but we camp in extremely cold temps occassionally, so I want the backup option.

ChanW · January 2022

@Tabulating, I don't know which Alde you have (what year is your Tab?), but the only member I can think of that replaced the main-board was with an earlier Tab.
I don't recall it being inexpensive. Considering the very few reports of failed main-boards that I've seen, I'm not sure that carrying a spare makes that much sense.
You might contact a dealer, or better yet, contact Alde directly, to find that info.

Sharon_is_SAM · January 2022

IIRC, @Verna replaced an Alde 3010
circuit board on her 2014 TaB.

Tabulating · January 2022

Thanks for the responses.
We have a 2018 T@b 400 with an Alde 3020.

I might still consider buying a spare board if I can get a part number.

Then I could replace the thermal fuse at my leisure. We really enjoy a hot shower at the end of our day. So, the board would be reasonable insurance.

Thanks

Bill

ChrisK · October 2022

Well, looks like my turn is up. We have one of the first Aides installed. Our T@b is officially a 2014 but was made in the fall of 2013. We woke up this morning at 2:30am to no heat, Alde panel not working. First, made sure we had working 110v and 12v in the camper. Fuses looked good but changed both fuses just in case. Nada. Unplugged 110v and 12v plugs to reset it just in case. Nada. Checked the the source 12v line in to the Alde with my multimeter and it read fine. Checked the outgoing 5v pins on the display connector on the board and nada. Then, I found this thread again. Set my meter for continuity check and put it across the thermal fuse and nothing. Guess I'll be ordering fuses today and pulling the board when we get home. Luckily, this is our last night of camping so I can just fix it at home. I'll be looking into a better way to mount the fuse to make it more replaceable or possibly getting a thermal switch.

My overall theory on thermal fuses is that, over time, they get "worn out" from general use and become less effective causing them to blow at a lower temp. We have 9 years and MANY miles and uses on ours.

What sucked is we carry a backup electric heater but when we turned it on, its thermostat was faulting. We could trick it in to staying on but that made the camper too hot. Fortunately, my wife is an excellent quilter so we had plenty of warm quilts to keep us warm.

ChrisK · October 2022

Finally had a chance to look in to fixing this. A stent caused a stint in the hospital first.
OK, so on to the repair. Like I said above, through testing, I determined the problem was probably the thermal fuse. Today, I found one of my jumper wires and bypassed the fuse and the Alde came right on (yes, I had reconnected it all first). Yup, bad fuse.

Image: https://us.v-cdn.net/5021717/uploads/editor/58/8wrkok5j5kq7.jpeg

First step was to remove the board. Sorry, forgot to get pics of this. Pretty easy though. Remove the cover and 2 screws hold the plastic board cover on. Unplug all the connectors up top. Take pics of them so you know what goes back where. There are 3 more connectors at the lower right part of the board (you can kind of see them in the second pic below). ChanW mentioned you have to have small hands to reach them but like he said, once you free the board from the housing, pull the board up and then unplug these then. Mark these 3 lower connectors well. 2 of them look identical and can be plugged in to each others' socket. I marked one with a silver sharpie as well as its location on the board. **Note** in the first pic, immediately below, there are 5 wires but there are 7 places they can plug in to. Note where you unplugged them from.

Image: https://us.v-cdn.net/5021717/uploads/editor/ma/pz1bkwtk89xg.jpeg

There are 3 plastic clips (2 on the right and 1 on the left as you are looking at the board) and 1 screw on the left side holding the board in. The screw is hard to get to but an extension from a ratchet and the proper torx bit had it out in no time. Yup, the cover for the board and the board itself are held in by Torx screws, not the usual square screws. Slide the board out and unplug the lower 3 plugs. I know this isn't a common failure fuse but I didn't want to go through all this again so I went with a similarly rated replaceable thermal fuse (noted in one of the posts above) so it was time for a little reworking. I clipped out the old fuse bu kept its "pigtails". I removed them from the board and soldered these to some wires that will go to the replaceable fuse.

This is the old fuse still in place.

Image: https://us.v-cdn.net/5021717/uploads/editor/uu/ba4yd3owu6tf.jpeg

Clipped

Wires soldered on to the pigtails. I did this to make soldering them to the board easier. Yes, I did put heatshrink on the connection. Even though it looks like I just soldered the wire to the side of the pigtail, they were folded over each other before soldering. More secure connection.

Soldered to the board

And routed, connectors installed and the new thermal fuse attached with Magic Tape. I did have to clearance the plastic housing a bit allow it to go back in place with the wires there. I thought about putting heatshrink over the connectors but there is almost 0 percent chance of something getting in there to short them out.

And the final result!

This really wasn't that difficult to do. Had I just replaced the thermal fuse with the same thing (I bought some of those too in case the replaceable one didn't work), it would have been even shorter. I wouldn't have removed the board completely, just leaned it forward to access the solder joint on the back side. Like I said in my post above, I think these things just wear out over time and eventually fail. It is not indicative of a true fault but a component that got faulty over time. I have the camper on to test it overnight to make sure it stays on.

MuttonChops · October 2022

ChrisK said:

. . . determined the problem was probably the thermal fuse. I found one of my jumper wires and bypassed the fuse and the Alde came right on. . . Yup, bad fuse.

This really wasn't that difficult to do. Had I just replaced the thermal fuse with the same thing (I bought some of those too in case the replaceable one didn't work),

Excellent, Well Done, and Thank You for providing some issue closure.

ChanW · October 2022

Nice details @ChrisK.

Only thing I wonder about is locating the thermal fuse right on top of the boiler.

I'd think the temperature of the circuit board area would be what the fuse should be monitoring.

ChrisK · October 2022

ChanW said:

Nice details @ChrisK.

Only thing I wonder about is locating the thermal fuse right on top of the boiler.

I'd think the temperature of the circuit board area would be what the fuse should be monitoring.

But is it the external or internal temp of the fuse that triggers it? I always assumed it was the fuse temp itself generated by the temperature of the circuit. As circuits fail, they get hot. 91C is almost 200F degrees. That's pretty hot even for a heater compartment.
One other thing is that location is not on top of the boiler. It is on top of the electronics compartment. Where the wires come out is where the fuse was. Should be about the same heat or even less as it is slightly insulated by the plastic housing.

Tabaz · October 2022

Nice write-up Chris (as are ChanW's). Can you guys think of a quick fix that could be done in the field maybe using alligator clips? If so, then that might be something we could have on board in case of an emergency.

ChrisK · October 2022

Tabaz said:

Nice write-up Chris (as are ChanW's). Can you guys think of a quick fix that could be done in the field maybe using alligator clips? If so, then that might be something we could have on board in case of an emergency.

@Tabaz Yes, a jumper wire with clips would be a good thing to keep around for a quick fix for this. I'd caution not to use it as a permanent or long-term fix. You can access the fuse without having to take the entire housing off. You can see it with just the plastic lid removed.

ChrisK · October 2022

@ChanW Looks like I was incorrect. This video shows how a thermal fuse works.

https://www.youtube.com/watch?v=ulEd-zmfcPM

It says "when the thermal fuse it heated from the external source". Thanks for the heads up. I'll move mine under the housing closer to the circuit board.

Tabaz · October 2022

What is the volt and amp rating for this fuse? Also, do you guys have a link to purchase one? Sorry, too lazy tonight to read the entire thread.

ChanW · October 2022

Here you go @Tabaz - Digikey:

https://www.digikey.com/en/products/detail/cantherm/SDF-DF091S/1014756?s=N4IgTCBcDaIMwEYDsBaBCyoHIBEQF0BfIA

ChanW · October 2022

@Tabaz , for an emergency, I'd be sure to have one or two of these fuses in my fuse stash, and then, yeah, I suppose alligator clip jumper wires would work, though I'd really want something more secure than alligator clips. Alligator clips seem to slip off at just the wrong moment, and then you've got an alligator clip falling into your circuit board area, which just might make toast out of everything!

If you're going to have the fuses on hand, you might as well make sure you also have some butt crimp connectors that fit the leads on the fuse. You could probably squeeze them 'just enough' to get a good friction fit, if you don't want to just crimp it onto the leads permanently.

This is all assuming one knows to disconnect all power to the Alde beforehand, of course!

A general NOTE! I take no responsibility for anyone attempting to follow my advice, and then burning up their Alde, their dear Tab, or even worse!

Tabaz · October 2022

Too late Chan. I used your advice and the alligator clips fell out and shorted the circuit board which then caused a fire in the pedestal. As the T@B caught fire, it ignited the jerry cans of spare fuel next to the trailer in my carport. Which then exploded the spare propane bottles next to the jerry cans. Then the natural gas meter next to the propane bottles ignited. Thankfully I was away buying supplies at Walmart for my next camping trip. Time to "Lawyer Up" big guy as Saul Goodman would say.

dragonsdofly · October 2022

@Tabaz haha! With no disclaimer on your part there's gonna be someone who reads this and freaks because they believe it! Xoxox
-Denise

Tabaz · October 2022

Denise - obviously my post is an attempt at humor and nothing more. While I'll always have "bad" feelings about Chan for discovering a fuse I missed in my "Fuses for Newbies" post, I grind my teeth, gird my lions, and attempt to get through each day knowing he bested me. Having this "ChrisK" person enter the discussion arena on Chan's side has not helped my ego one bit.

ChanW · October 2022

I just got a ticket to Mexico.... I'm outta here!

ChanW · October 2022

No fair @Tabaz you've clearly had your coffee already.
Mine just went out my nose!

Tabaz · October 2022

If there ever was a "ChanW" fan club, I'd be the Arizona chapter president. All your posts are insightful, helpful and sometimes downright brilliant. Every now and then (but not often), they are even funny.

pthomas745 · October 2022

"I'll just use this jumper I made! What could go wrong?"

ChanW · October 2022

Aw @Tabaz , I know all that. But darn it! You shouldn't have mentioned it.
Now that my wife knows it, she's going to expect a whole lot more from me!
(T hanks!)
And they'd be funny-odd, more likely, eh???

ChrisK · November 2022

Tabaz said:

...gird my lions...

How does one do this?

Tabaz · November 2022

I see the problem - it should have been "loins" not "lions." I have no lions to gird.

Image: https://us.v-cdn.net/5021717/uploads/editor/u1/pq8gpwt3mwyu.jpg

Going with this set-up. Resettable fuse. Will cut the jumper wire and solder the alligator clips to a few spade connectors. Will keep on board in case of emergency.

ChanW · November 2022

Girded lions.... Hmmm!

@Tabaz , interesting solution.

Is that resettable fuse thermal activated? (Otherwise, it seems it would be equivalent to only a jumper wire...)

Tabaz · November 2022

My tech friend picked it out based on your prior post:
https://www.amazon.com/dp/B08RBLRZPP?psc=1&ref=ppx_yo2ov_dt_b_product_details

ChanW · November 2022

Nope, I don't see anything in the Amazon description indicating it will protect your circuit when the temperature gets too high.
I wonder why they call it "thermal" in their description.
You'd want to find something that protects up to a specific temperature - in this case it's 91°C you need as the protection point.)
It seems that this one is only designed to pop when the amps get too high, same as a fuse or circuit breaker.
See if you can find the manufacturer's spec sheet for the device. Maybe it's in that.

RCB · November 2022

As explained this fuse either fails from excessive heat or in time loses its thermal resistance as a result of ambient heat in the Alde compartment. What is curious the UK manual states the system will reset if the control panel is turned off for a period of time. There is no such reference in my 2018 (2019 installation) manual.
Perhaps the ambient temperature in the Alde compartment can be somewhat reduced by leaving tge exterior access pane ajar or installing an operable vent in the door ie: a rotating ss butterfly type.

Denny16 · November 2022

We left our Alde running on low temp setting (50F) last winter, so the glycol was heated during the night, and we have not had any issues with the thermal fuse or the Alde unit/compartment getting too hot. We also ran the Alde for hot water on our summer camping trips, one of which was in 90+F temps, without any overheating issues.

Cheers

Found a fix for "No Alde heat" when all fuses are good

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