Wet bay heater question

[Chuck H]

I'm pretty sure my Back Seat Heater Plus in the wet bay gave up the ghost because it won't come on via normal operating procedures. I tried using a jumper wire at the snap disc to check if the heater would come on and that didn't work. The switch on the left that controls heat and fan operation is really hard to move. When turning the thermostat knob I can hear a clicking noise which is the same noise I heard when bypassing the snap disc with a jumper wire. My question is does the same snap disc operate both the bay heater and the tank heating pads simultaneously? The on off switch inside at the control panel  comes on but not the light next to it. Considering using thermostatically controlled light bulbs. Any ideas or suggestions would be greatly appreciated. Thank you in advance!!!

1 hour ago, Chuck Hefti said:

I'm pretty sure my Back Seat Heater Plus in the wet bay gave up the ghost because it won't come on via normal operating procedures. I tried using a jumper wire at the snap disc to check if the heater would come on and that didn't work. The switch on the left that controls heat and fan operation is really hard to move. When turning the thermostat knob I can hear a clicking noise which is the same noise I heard when bypassing the snap disc with a jumper wire. My question is does the same snap disc operate both the bay heater and the tank heating pads simultaneously? The on off switch inside at the control panel  comes on but not the light next to it. Considering using thermostatically controlled light bulbs. Any ideas or suggestions would be greatly appreciated. Thank you in advance!!!

Sorry for the duplicate pics

Edited October 12, 2021 by Chuck Hefti

[Dr4Film]

Chuck,

You can remove the extra photos by clicking on the three horizontal dots in the upper right corner of your post and choose EDIT.

Then delete the the extra photos leaving the ones you want, then click on SAVE.

In regards to the heater, there may be a fuse inside the heater. Mine was DOA when I first bought the coach. It had been removed and it was sitting in one of the storage bays. Tossed it in the trash and installed a custom RoadPro heater using the same wiring but had to add one relay to replace the relay that was inside the old rusted bay heater.

Your System Heat switch consists of a switch and an adjacent indicator light. When you turn on the switch it activates the Tank Heater Pads and sends power to the snap disc. Once the temp drops to the snap disc setting the snap disc will close and send power to the relay which in turn activates the heater. When the disc closes the indicator light should light up.

I have attached a wiring diagram of the Bay Heater and Tank Bay Heating Pads.

Hope this helps.

Bay Heater.pdf

Edited October 12, 2021 by Dr4Film

[Chuck H]

Richard,                                                           Thank you for your reply!      Why and where did you install a relay? I'm electronically challenged so please bare with me.

[Dr4Film]

I mounted the relay on the side of the Service Bay. The relay is used to transfer 12 VDC power to the RoadPro heater with larger gauge wires due to the amps that the heater draws when on. The wires used for the System Heat Switch are a much smaller gauge plus they travel a long distance to the Service Bay.

[jacwjames]

Richard

My 2002 Windsor came with wet bay heater but not the tank heat pads.  It appears though that it came prewired for the tank hear pads,  I found a 10 awg wire tucked up the black water tank. 

I looked at the diagram and the way I read it is that the snap disc controls both the wet bay heater and the tank heat pads.  Am I right???

I am contemplating installing the heat pads, do have them.  The ones on the drawing show 9 amp, so ~+100 watt each.   I think it would be pretty easy to install on the fresh water tank as I can lift it up enough to slide them underneath.  Not so much on the black and grey tank as the plumbing on top would restrict how much I could lift them up.  Any thoughts on whether it would be worth installing the tank heat pads???

[Chuck H]

Thanks Richard for the pics. Great idea for a replacement heater,  looks smaller too.

[Dr4Film]

21 hours ago, jacwjames said:

Richard

My 2002 Windsor came with wet bay heater but not the tank heat pads.  It appears though that it came prewired for the tank hear pads,  I found a 10 awg wire tucked up the black water tank. 

I looked at the diagram and the way I read it is that the snap disc controls both the wet bay heater and the tank heat pads.  Am I right???

I am contemplating installing the heat pads, do have them.  The ones on the drawing show 9 amp, so ~+100 watt each.   I think it would be pretty easy to install on the fresh water tank as I can lift it up enough to slide them underneath.  Not so much on the black and grey tank as the plumbing on top would restrict how much I could lift them up.  Any thoughts on whether it would be worth installing the tank heat pads???

Most likely the wiring harness used in building our coaches is pretty similar. Just depends on the options asked for at the time of purchase.

The Tank Pads are not controlled by the snap disc. If you look closer at the wiring diagram the 12 VDC positive for the pads is a RED wire that goes over to a relay PRIOR to going through the Snap Disc. What is not shown on the diagram is the relay which is inside the Service Bay heater.

When you turn on the System Heat switch, power is sent to the Snap DIsc and also to the Tank Pad relay. The relay closes powering up the Tank Pad heaters. The Service Bay heater will not get power until the Snap Disc located in the bay closes.

Does this make sense?

I will leave the decision up to you as to whether they are worth installing or not. It really depends on where you like to travel. Since we go to Alaska due to my sons and grand-kids living there, I have used the System Heat on occasions in Canada & Alaska. We get there early in May and leave just before snowfall in late September. If the temps are in the low 40's I will turn the System Heat switch on.

Also, we have Aqua-Hot which has a Heat Exchanger just for the Tank Bay. So we have a secondary heat source for keeping the tanks in good shape.

[Scotty Hutto]

As someone who doesn’t have an Aqua-Hot (😢), the wet bay heater and tank pads are a lifesaver.  

It took a while to get everything operating correctly. The biggest culprit on mine was the thermal fuse inside the heater.  There is a great write-up on how to repair that. I bought a pack of those fuses and crimps; let me know if you need a couple. 🤣

As anectodal info, it doesn’t get *that* cold in Atlanta, so we don’t winterize.  The coach stays plugged in to a 15a circuit and I have temp sensors in the coach and wet bay that send me a text if it’s getting too cold. The wet bay heater keeps the wet bay in the high 40’s low 50’s down to about 20°F. Maybe lower, but I haven’t experienced lower temps since getting everything fixed. 

[jacwjames]

Thanks Richard

Makes sense that the tank pad heaters wouldn't be controlled by the snap disc since it will go on/off pretty quickly and not let the tank pad heaters get warm long enough to do any good.   I'll have to do some testing on how mine is set up and see if I can actually get power to the wires I found above the black tank.  What was funny is that they did not cap them, they were just cut wires inside the protective loom. 

Since I don't have a secondary heat source it might be worth while to get tank heaters in place.  I could look at installing a second switch in the bathroom to turn just the tank pads on/off if the system heat is on. 

Looking at other options for a backup heating system if I do make this cold weather trip. 

I will probably look at installing the Reflectix R-21 insulation in the windows and maybe some of the cabinets, every little bit helps. 

[Chuck H]

Update:  A friend of mine told me he actually found by accident while at one of our local RV Dealers the exact wet bay heater that is in our Coach, so I purchased it($123 plus tax). I had to lengthen the wires on the new unit because they only stuck out about 2" from the back and had 1/4" spade connectors. I added 4" on each of the wires( white,red and black) using the same wire that came with the heater using 1/4" spade connectors to attach to the heater wires on the back. I then cut off the old snap connector and soldered it to the other end of the spade connectors and snapped it to the coach wiring. I tested the snap disc operation by setting it on an ice cube and everything works like it should except it seems the wiring is getting a little to hot for my liking. Is that normal? Any thoughts would be greatly appreciated. Thank you!

[jacwjames]

So wife got back from her dog show and got a chance to check the wiring for tank heaters. 

Turned the system switch on and tested voltage across the circuit breaker to the relay.  That was all good but no power through relay, the blue wire that is for the system heat was not triggering the relay.

So I jumped the snap disc and that closed the relay and sent power to the wires for the heat pads.  So mine is wired differently then the schematic that Richard posted.  On mine the heat pads will only come on when the snap disc closes.  Not sure if that is good or bad.  I could look at rewiring so the tank heaters will come on with the system heat switch.  I'll have to think about that.  Most of the tank pad heaters I've seen have internal temp sensors and will only come on when it is cold enough to it may be a mute point.  

It does not show any fuses to protect the pads like one Richard posted, which I will add. 

Here is a screen shot of the wiring for my coach, hit CTRL5 if it is blurry

2002 Windsor wiring wet bay heater.pdf

[Jim McGarvie]

4 hours ago, jacwjames said:

 ...hit CTRL5 if it is blurry

I give up, what is "CTRL5" in Mac lingo? It is not legible as is.

Thanks.

 

[jacwjames]

2 hours ago, Jim McGarvie said:

I give up, what is "CTRL5" in Mac lingo? It is not legible as is.

Thanks.

 

Not sure, I'm Windows

I have to hit the CTRL   &  5 keys at the same time to clear up the picture,

[Jim McGarvie]

9 minutes ago, jacwjames said:

Not sure, I'm Windows

I have to hit the CTRL   &  5 keys at the same time to clear up the picture,

What program are you viewing it with? And do you know what it calls that shortcut? Something in the View menu or something?

[jacwjames]

This is a PDF file, I received the original from Monaco Tech support years ago.  Most of the pages are normal, when you zoom it they are clear/readagle.  This page is shrunk down and I have to zoom in at 800% to be able to see/read, but it is blurry until I hit CTRL 5. 

So to have the view saved I just "print view" to a PDF file but it is blurry when you first open. 

Not sure what the solution would be.

Edited October 19, 2021 by jacwjames

[Deepseated]

Hello, new to this site after troubleshooting the latest issue with our coach.

Headed up to the snow and found the bay heater not working. Tested the snap switch, failed, found a replacement on Amazon: Senasys Snap Disc Thermostat Switch - Circuit On At 35°F and Off At 45. Number 2511L002-2132. In bench testing the heater, I discovered the fuse in the picture was open. I pried the cover off and closed the copper tabs until reading .2 OHMS across on a meter, the heater then functioned properly on the bench. 

My bench test setup, from the plug on the heater unit was red and white to positive, black to negative. The heater ran down a 12v motorcycle battery in 30 seconds. 

This website helped a bunch so I wanted to post my findings.

 

Chris

[Deepseated]

Success! 

Thanks again for the terrific guidance I found here.

Chris

[cbr046]

I replaced the original internal thermal fuse with one from Newark Electronics SKU 39T4439

https://www.newark.com/thermodisc/g5a01184c/fuse-thermal-184-c-20a-250vac/dp/39T4439

that was rated for 20A and 184C and replaced it back in April.  It's blown again.  Fortunately I ordered multiples, and replaced it (again), but is there a better / higher rated thermal fuse?

- bob

[Deepseated]

Bob,

If the heater is blowing fuses, likely the heating element is pulling too many amps maybe from age.

I would bypass the thermal fuse for a second and measure amp draw if you haven't already.