Hugh1959 Posted July 19, 2022 Share Posted July 19, 2022 I have low voltage to my water heater switches which indicates lose connection or damaged wire. My problem is finding how the power goes from rear 12v panel to control panel switches for 12v and 120v water heater . Anyone know? Does it go to water heater first? Link to comment Share on other sites More sharing options...
jacwjames Posted July 19, 2022 Share Posted July 19, 2022 Do you have a wiring diagram? What kind of water heater do you have? My water heater 120 volt circuit is controlled by a 12 volt switch located on the base kitchen cabinet near the stove. It sends voltage to a relay that is located behind my main electrical panel, hard to get to. The relay is a 12 volt/120 volt relay, when you press the 12 volt switch in closes the relay that sends 120 volt to the water heater. I found the relay when I was working on my EMS control board, when I checked the relay the 120 volt terminals showed signs of getting hot so I replaced the terminal connectors. I did buy a spare relay thinking eventually I'd need it. Last year I was working on my electrical again and check the relay again and found the terminals again showed signs of heat, so replaced terminal ends again. Link to comment Share on other sites More sharing options...
Bill R Posted July 19, 2022 Share Posted July 19, 2022 Hugh, My 12V relay is located in the bay behind the Hot Water Heater. My HWH gets its 120V from an outlet in the same bay. Check to see if yours is there. I had a similar problem and found a bad chassis ground connection for the 12V relay where it attached to the HWH tank ground. All the best. Link to comment Share on other sites More sharing options...
Hugh1959 Posted July 20, 2022 Author Share Posted July 20, 2022 I jumper my 12 v inside control panel to supply 12v to water heater which makes everything work. What im looking for is how the 12v normally runs to switches in control panel. Supply comes from bed room and is good. Power at switches low and goes to nothing when switches turned on, but ok with alternate 12v supply. Water herter in Atwood 2007 Link to comment Share on other sites More sharing options...
jacwjames Posted July 20, 2022 Share Posted July 20, 2022 Do you have the wiring diagrams for your coach, they sometimes provide a clue. If you go to the downloads section and look under electrical there is a set for a 2002 Knight. You may have to buy a tone tracer to be able to find the path of wires. You hook it up on the end you have access to and then start following the wires. I bought a cheap one that half way works, it did help me solve a problem with my coax cable in the BS. So if you buy one spend the $$$ to get a good one. Link to comment Share on other sites More sharing options...
RS lakeshore Posted July 20, 2022 Share Posted July 20, 2022 What would you consider a good tone tracer. I would like to purchase one but know nothing about them. thanks Richard Silcox Link to comment Share on other sites More sharing options...
jacwjames Posted July 20, 2022 Share Posted July 20, 2022 Can't comment, I needed one fast so ran up to Harbor Freight, the tracer works but not great. Maybe someone else can recommend a good one. I had looked at Triplett Fox and Hound, they have gone way up in price since I last looked at them. Link to comment Share on other sites More sharing options...
Ivan K Posted July 20, 2022 Share Posted July 20, 2022 I have been using this one since I retired and lost access to a commercial type. It works as it should but the rubbery coating got sticky after years. I know it can be cleaned up and it's good enough for me. Used it to find a wire break in ABS system and in many cars. Link to comment Share on other sites More sharing options...
RS lakeshore Posted July 21, 2022 Share Posted July 21, 2022 Thank you will check it out looks good. I have had 3 items that the rubber got sticky one was my heat gun handle. I ended up putting saran wrap on the handle. Cheap fix. Link to comment Share on other sites More sharing options...
Gsmentko Posted February 12, 2023 Share Posted February 12, 2023 On my 2007 Knight PDQ my toggle for 120 v hot water heating is on, but there is no power to the outlet the hot water heater plugs into. I took apart my main circuit breaker panel and looked behind it and no relays. I opened the hot water heater compartment and the romax goes through the wall with no relay in there either. I can't find the relay the 12v Switch operates for 120v to get to the hot water heater outlet. Does anyone have any idea where that relay is? My Circuit panel is in the back bedroom closet on the drivers side. I am heating my hot water with propane and want to switch back to AC powered 120v. Link to comment Share on other sites More sharing options...
jacwjames Posted February 12, 2023 Share Posted February 12, 2023 What Make/model water heater do you have? Link to comment Share on other sites More sharing options...
Tom Cherry Posted February 12, 2023 Share Posted February 12, 2023 38 minutes ago, Gsmentko said: On my 2007 Knight PDQ my toggle for 120 v hot water heating is on, but there is no power to the outlet the hot water heater plugs into. I took apart my main circuit breaker panel and looked behind it and no relays. I opened the hot water heater compartment and the romax goes through the wall with no relay in there either. I can't find the relay the 12v Switch operates for 120v to get to the hot water heater outlet. Does anyone have any idea where that relay is? My Circuit panel is in the back bedroom closet on the drivers side. I am heating my hot water with propane and want to switch back to AC powered 120v. Pull your prints. Look for your Energy Management System drawing. The first thing I would do is to pull ALL AC power….as in don’t be plugged in or have the Genny running. Remove the panel from the breakers. There will be a Printed Circuit Board on the lower left side. That is what MAY be your problem. There is a relay on this board that controls the Water Heater. Read page 159-160 and understand the functions. So it the relay is bad….no AC. The FIRST thing is to reset and say a small prayer. You will find 2 or 3 pigtails. There is a 3 Amp fuse. Pull the pigtails off and pull the fuse. If you have a Salesman switch near the door, turn it OFF….push the bottom of the button. This and pulling the leads and the fuse totally powers down the EMS. Let it sit for half an hour or so. Then put the pigtails back on and then the fuse, if you have turned off the salesman switch, turn it back on. That reset the EMS control. Now, see if you have power to the water heater outlet. If NOT, you have, most likely, a bad relay in the EMS PCB. You need to trace the power from the breaker. I can’t remember, but I think the breaker is powered off the Buss of the main panel. Then the positive or Black goes to the relay on the EMS. It is NOT uncommon to lose a relay on the EMS board. Do some circuit tracing, live 120..IF YOU HAVE THE SKILL SET and compare to the print diagram. Link to comment Share on other sites More sharing options...
Hugh1959 Posted February 13, 2023 Author Share Posted February 13, 2023 (edited) I have 2007 monaco knight 38pdq. And the relay is behind the water heater. There is also 120v plug into outlet located there. Access is inside bay besides the water heater. Open door, pull out drawer and squeeze into bay. 12v from the switch outside bathroom on panel operates gas and with the switch next to it operates with 12v thru 120v relay. All this 12v go thru the water heater control box first before the 12v relay. Edited February 13, 2023 by Hugh1959 Added year Link to comment Share on other sites More sharing options...
Solution Gsmentko Posted February 13, 2023 Solution Share Posted February 13, 2023 Tom, Thank you very much. I did the reset process (unplugged, turned off sales switch, turned off inverter on smart panel, then took 3 pigtails apart and the fuse). Waited 45 minutes and put it back together an no win. Started live checking the printed circuit board and found CB4 had power in, but Rly4 had no power out. All the others did. So I swapped Rly3 and Rly4. Then tested the power outlet behind the water heater and it was hot 124V! Yeah. I then put them back to original wiring. I then went to my control panel and took it apart and checked continuity on the 120V heater switch and found it tested out fine (It does light up when on too). I also jumped the 12v wire to the out 12v and it didn't make any difference on the output of Rly4. So, looks like a bad relay. So, Now, what are my options? It is a Intellitec distribution panel model 750. I can only think of these two options... 1) See if I can buy a new printed circuit board? Haven't found the exact one yet, but looking to be around $300 - $400. The bottom picture below says they don't sell the model 750 and I would have to change to Model 900. Does that mean I would have to buy all 4 items listed below? 2) Bypass the relay and go direct from the 20A circuit breaker? Then, turn the circuit breaker off when I don't want electric hot water in the main panel instead of at the control center? Anything wrong with that? It really just turns that outlet off or on remotely like the salesman switch, right? Thanks, Greg Link to comment Share on other sites More sharing options...
jacwjames Posted February 13, 2023 Share Posted February 13, 2023 When my EMS crapped out I upgraded to the 760 series and had to get a new load display and a couple wiring harnesses. At the time (2014) it cost ~$450. I bought what I needed from M&M Electronics. Where ever you purchase from you just have to make sure to get all the necessary components. Link to comment Share on other sites More sharing options...
Tom Cherry Posted February 13, 2023 Share Posted February 13, 2023 You are now an advanced EMS trouble shooter. GREAT JOB. As to what to do….I can’t tell you. I don’t have the prints….so, you need to make me “smart”. Is there a SEPARATE relay downstream that allows you to select 12 v 120….as in CUTTING OFF THE 120 and the WH then switches over. I HOPE you have the manual for the EMS….if not, download it. Then read it. Now understand it. Monaco CHEATED. They were supposed to use the three relays marked for the AC and run 12 VDC lines from each AC to each of the relays. your manual on page 160 or so shows the shed order…..top or first shed is this. Water Heater (rly 4), Rear AC (3), Washer Dryer (2) and Front AC (1). What they SHOULD have done is set Rly 6 for the Front AC (on the AC side) as last, then rly 1 (Washer Dryer), rly 5 (AC Side) for the Rear AC and then finally, rly 2 for the Hot Water side. YOUR issue…you have NO rear AC now. You have options….and this is the overview… Wire Nut your Water Heater to the breaker and put the Rear AC back on Rly 3. Since I assume you are on 50Amp service….you are good to go. Then consider the following…. Boards are hard to find and expensive, chase one down and buy it. Understand HOW to install….but keep it. James just chimed in and confirmed that. M&M did have to make custom harnesses…..as your post indicated. I will help you offline learn HOW to revise your existing board…to salvage it. You will need to purchase a 12 VDC coil relay with contacts rated, FLA, for 20 amps 120 VAC. Then you will hook up that relay, which will have to be in an electrical (plastic) junction or handi box and mount it somewhere. Maybe behind the main panel….I don’t know your space limitations. THEN the HVAC (for thermostat) rly 5 (or 6) will be used to shed that relay. So, then you are actually using the EMS as intended and the AC is being shed or controlled by the 5, 6 or 7 relay or switch that Intellitec originally designed it for. I have thought about this many times and finally “noodled it out” in my head. In theory, Intellitec wanted Monaco to turn OFF the thermostat signal to each unit….but they chose not to. But, turning off the AC using a secondary relay accomplished the same thing. So when you lose, as you did, a relay, you can salvage the board for less than $25. SOME folks have said they could not find a new relay to install on the board…..so they may chime in. This will work. Link to comment Share on other sites More sharing options...
Gsmentko Posted February 14, 2023 Share Posted February 14, 2023 Thanks Tom, Yes, I have the manual and going through it. I do have the AC connected back to Relay #3. Original wiring configuration. Schematic or Prints for my 2007 Knight 38pdq? Ha, Ha... Asked Monaco for them a few times and they are hands-off before the bankruptcy and reorganization. I downloaded quite a few from this group of close RVs in year or model but they are not helping much for past problems. I'm not sure one for mine with be 100% accurate... For example in my rear fuse panel I blew a 15amp fuse and took one out of one labeled "OPEN" to fix the blown fuse (assuming the OPEN ones are like spares). A day later I noticed some lights weren't working. So, after buying a new pack of fuses, and put it in the OPEN fuse that light worked again. I understand what you are saying about buying a new relay and wire that one and keep it separate. bypassing the EMS board for #4 Circuit. Yes, I will need some help to understand how to wire the signaling to it, so it will function as designed for both the on/off toggle on the control panel as well as for the EMS shedding. That will be hundreds of dollars cheaper than a board. I'd like to work through that. My email is: hsjasg@hotmail.com Please send me a quick message and we can talk. Thanks, Greg Link to comment Share on other sites More sharing options...
jacwjames Posted February 14, 2023 Share Posted February 14, 2023 I have read that some knowledgeable people have been able to replace the bad relay. But you have to have the right type of tool to be able to remove and then replace. Link to comment Share on other sites More sharing options...
Tom Cherry Posted February 14, 2023 Share Posted February 14, 2023 44 minutes ago, jacwjames said: I have read that some knowledgeable people have been able to replace the bad relay. But you have to have the right type of tool to be able to remove and then replace. Yes, So the average member here may not have that. Frank and Paul and a host of others can remove the relay and replace them. I MIGHT be able to...but I don't choose to learn that skill set. What I am proposing, and I will copy you on the PM explaining it, is that you purchase a 12 VDC coil relay with contacts rated for the FLA of the HVAC and have 120 VAC rating. I just found one on Amazon and it is very inexpensive. Then you power the relay from a 12 VDC (the EMS has power) and then you use the NC side of relay 5, 6 or 7. Those relays are actually DPST and NOT the SPST style of Relays 1 - 4....which are used for switching AC. Those contacts were supposed to be for non or lower inductive loads like the HWH or the WD. I don't understand WHY the HWH on Relay 4 failed....but it did. I am still noodling over this. In reality, the way I THINK it should be done is to use Relay 5 (the HVAC Thermostat contacts) and put in the new relay. THEN, move the rear HVAC 120 VAC load to that relay. That then reduced the risk of killing Relay #3 which is where his HVAC is now. Then you reprogram the EMS to shed in the same order. Right now, as long as there is 50 Amp, wire nutting or bypassing Relay 4 is acceptable..... EDIT. I used the word WIRE NUTTING. This is an ACCEPTABLE practice since he is at a CG and is a FT. If he was traveling, then the wires would have to be crimped as a Wire Nut is not an acceptable connection for a Motor Home It needs to be crimped or a terminal strip with a fastener or clamp....END OF EDIT That's it.... If one of our members had a spare board and and would use that as a "Core" or swap, that would be great. This is evolving.....I will copy you on the PM....as you I'd like your opinion..... I ran this by Frank and he said it would work. OF COURSE, he would repair the board....but that would then require wire nutting all the connections and running without it....which could be done..... Link to comment Share on other sites More sharing options...
Bill R Posted February 14, 2023 Share Posted February 14, 2023 23 hours ago, Gsmentko said: Anything wrong with that? Greg - I have heard of others doing this. You become your own EMS by knowing how many Amps your power source is and what demand you will be putting on the system. If you are plugged into 50A shore power the EMS shedding is mute because you should have enough power for the loads. It you are on generator/30A/20A you want to manage the other loads while running the 120V hot water heater. Link to comment Share on other sites More sharing options...
Gsmentko Posted February 14, 2023 Share Posted February 14, 2023 Thanks, And that is what I do now. I only turn on 120v water heater when I'm on 50A. Sometimes I forget and see the 120v light on and turn it off when I see it later in the day after I break camp that morning. I'm just unsure what would happen and my inverter is running (as I installed a residential fridge after my gas/electric died... and a full sign wave inverter!). Could I overload something before I remember to shut off the 120v WH. Im thinking it is low risk. Greg Link to comment Share on other sites More sharing options...
Bill R Posted February 14, 2023 Share Posted February 14, 2023 2 hours ago, Gsmentko said: Could I overload something before I remember to shut off the 120v WH. Greg - if you are not on shore power or running the generator, then the 120V panel is not energized and is separate from the 120V circuits supplied by the inverter. The red light is just showing the switch is on but no 120V to the hot water heater in this instance. It is fine. If you want hot water in this case you use the 12V switch for the hot water heater to use propane heat. I am sure you already know that. Link to comment Share on other sites More sharing options...
Happycarz Posted February 18, 2023 Share Posted February 18, 2023 My coach, built in early 2007, has the Intellitec 760 board. The relays for the 760 board are available from Amazon, albeit at a substantially higher price than the electronic supply houses. If you are good at desoldering and soldering the relays on the board, this is an alternative from the way mentioned above. Relays: Omron G8P-1A4P and G5LE-14 1 1 Link to comment Share on other sites More sharing options...
Tom Cherry Posted February 19, 2023 Share Posted February 19, 2023 1 hour ago, Happycarz said: My coach, built in early 2007, has the Intellitec 760 board. The relays for the 760 board are available from Amazon, albeit at a substantially higher price than the electronic supply houses. If you are good at desoldering and soldering the relays on the board, this is an alternative from the way mentioned above. Relays: Omron G8P-1A4P and G5LE-14 Thanks….these seem to be a little simpler than SMD. @Frank McElroy please include in the PL when you update and release again. This is great info. I thought the relays were more of a PITA to remove and replace..that is why I concocted Plan B. Good to know.. Link to comment Share on other sites More sharing options...
Gsmentko Posted February 26, 2023 Share Posted February 26, 2023 Update on my EMS board problem. I found the correct parts and they are on order and I am planning on taking the board out and replacing the relay... Eventually... So, since I'm bypassing the bad relay on the EMS board (direct from Circuit breaker to the outlet) I turned the 120v water heater switch off and the next day I had no hot water. I checked the 120v outlet behind the heater and it was live at 120v. Hmmm.... So, I'm guessing the 120v Switch turns off/on some component in the hot water heater itself. The EMS board is only for shedding and not controlled by the 120v water heater switch. Not how I thought it worked, but seems to be that way. Just passing this on, but I could of been the only one thinking wrong. Greg Link to comment Share on other sites More sharing options...
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