MarkHymer Posted February 3, 2020 Share Posted February 3, 2020 Hi All, First post, Hope this helps someone in the future. First time i think someone has posted the PCB fix, in English at least! Had a problem with my 1998 Hymer B544 Truma boiler and had a frustrating time with service/spares, so managed to fix it myself. Please find below the thread i posted on another forum for anyone who has the same problem. I've posted only my half of the conversation so you can get a picture of the full problem if troubleshooting yours :) Link to comment Share on other sites More sharing options...
MarkHymer Posted February 3, 2020 Author Share Posted February 3, 2020 Recently bought a Hymer B544 1998 (My Dream Machine) and quickly found the salesman had lied on many points, Found the dash had rotted, roof was leaking, water pipes were leaking - most things were shot really - I understand second had motorhomes have a few things wrong, but this took the cherry on the cake. Jumped in and started reno's, as been the MH i always wanted - decided just to make the best of it and also allowed me to put a stamp on it, so: -Made a new Dash - New Sound proofing -Cut new carpets -Replaced skylights - Sealing all external joints - Began spray painting all plastics, walls - Rebuilt the cupboard, passenger side - Fixed External door locks The list goes on, Then.............. The boiler failed I'd saved up such a long time and reno's have cost so much despite doing the work myself, this really was the cherry on the cake! Now the colds coming in, i can't continue to work and my holiday is just about done If anyone can help with this i would be very grateful! So the problem: Boiler was working fine on both Blown Air heating and Water. Gas: Propane Regulator fitted: 30Mbar Boiler: C3402/6002 Boiler: Gas only Gas at the cooking hobs - No loss in pressure when i turn the boiler on Boiler exhaust fan blowing: Checked the outlet for pressure Igniters sound to be clicking: Unsure about spark Gas valve 'sounds to be opening' Fuses on PCB are all checked and fine If anyone has ANY thoughts at all i would greatly appreciate it - Maybe you know the startup sequence sounds, or know its jippy if its cold outside etc everything helpful. If you can find the solution, when we meet somewhere in MH land, i'll by you a pint or two! Best Regards Mark Link to comment Share on other sites More sharing options...
MarkHymer Posted February 3, 2020 Author Share Posted February 3, 2020 Just an update + future reference for anyone else, Replaced the gas regulator and no change. Will try and get time tomorrow to take the boiler apart and see whats going on, Link to comment Share on other sites More sharing options...
MarkHymer Posted February 3, 2020 Author Share Posted February 3, 2020 Afternoon all, Many thanks for the responses, its really appreciated. An update. The gas is Propane - Bought a new cylinder with the regulator to make sure there was no issues that side of things Put the voltmeter over the igniter transformer and all good there, but haven't visually checked inside the chamber yet. Also attached a battery onto the boiler and no change: But thanks for the suggestion, was a great thought. Took out the Gas valve....and... In its run up sequence i blew down the valve to see if it opens - NO. Which means hopefully one of two things : Gas Valve or PCB... Tested the PCB for voltages on the solenoid terminals as i find it hard to believe that pretty much both 'solid state' solenoid devices would fail (From what i understand the two solenoids are for Low and High demand, hence sequential) . I tried to put something ferrous into the solenoid to see if it moved but no result... The PCB drives the solenoids so if there not working its most likely the PCB which is around 400 pounds i believe) I've ordered a new gas valve and will fit and update- just hoping its not the PCB, a bit pricey. I'm sure looking at it if we could get a PCB diagram it would just be a 50p relay that controls the solenoids... Anyway the gas valve is 75 pounds so i'll eliminate that first and keep all updated for future reference. Spare supplied by : https://www.leisureshopdirect.com/ga...trumatic-c3400 (Also for others with the same problem or troubleshooting and found this through google, The run up sounds are - Exhaust fan (Also Blower fan if on air heating only), then solenoid valve opening (Click), then the igniters clicking. But what through me, was the igniter makes a loud CLICK before starting its sequence of sparking, that i mistook for the gas valve opening) Link to comment Share on other sites More sharing options...
MarkHymer Posted February 3, 2020 Author Share Posted February 3, 2020 Also for future reference, if some one finds this googling and is non technical: Picture of the Gas valve - The grey boxes on either side are the solenoids: They create a magnetic field to move the internal valve. One is for Low gas demand and the other comes online also for High demand. - Can't get the picture in :( won't allow the upload. Google the above words to find the original post guess - Link to comment Share on other sites More sharing options...
MarkHymer Posted February 3, 2020 Author Share Posted February 3, 2020 OK SO......................! If your following this thread because your from the future and have the same/similar PCB problems please go to the bottom for the solution and save a lot of money hopefully So it wasn't the gas valve - Found that the solenoids weren't energizing by putting something ferrous in them like an iron nail, Ordered a new PCB - this is where the saga began - Got next day delivery...Waited for one week, rang them and..... Me: Hi, did you manage to post the PCB? Shop: No, Me: Have you got it? Shop: Yes, lots of them, Me: I paid for next day delivery.... Shop: Sorry were in 'Holiday mode' right now Me: Whats that? Shop: We just haven't posted anything Me:......... Right i'll come down and pick it up then, 3 hour trip and turns out it wasn't the right part at all.... not even remotely to do with the boiler.!....a simple power supply. After the guy had tried to tell me that the pictures of the items can be different and it IS the part i ordered (Keep in mind how different these things are - Like a bike and a plane) i promptly showed him the boiler PCB, his Ebay PCB picture (The same thing) and the idiotic power supply he was holding. I was so mad that they'd just wasted one week and were so arrogant and idiotic i walked out, i got home and decided to just fix the dam thing! 2 pints of Guinness, - jiwawa the GREAT BEVERAGE and one night with the multi-meter, went through the PCB and found the component that failed. I'll post a pic so people know what i'm talking about, I'm without a circuit diagram, so presuming some of this and proved some of it with the fix... Please correct if i'm wrong, always happy to understand things more! There's 5 relays on the board, i've proved the 2 for the solenoids (One each), the other 3, i presume one for the air supply fan, one for the gas chamber fan, and one for the igniter. (The Relays are the white boxes for the uninitiated into electronics ) The solenoid relays are the two next too each other, I've marked the one that failed with a pencil X in the picture. Also i guess the capacitors below them are to counteract the inductance in the solenoid relays. Found that one of the relays was not switching on one half of its legs. Googled the relay to find the switching pattern and used a multi-meter on the beep or resistance setting to test. Don't be put off , this is easy to do! Researching the relays i found an updated version, indicating this version must not of been so reliable.... I would bet that most 'PCB' failures on these boards are 90% relay faults as their the only moving part! Find the updated replay part number below in the solution. If you want to know how to test a relay its probably easiest just to google/youtube. Also google the part number to get the data sheet to find the latching arrangement. ++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++ GENERIC SOLUTION FOR PCB FAULTS ON TRUMA 3402/6002 ++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++ If you've been told its your PCB and replace it, i would recommend doing a few simple things first to save up to $400, don't feel overwhelmed its all simple logic by definition If you know whatever part of your boiler hardware works, i.e. Fan, Igniter, combustion fan, solenoid by just putting 12v dc direct to it, then your fault is more than likely on the PCB, On the PCB its more than likely a relay which is $3 max to replace, Youtube how to test a relay ( I did it using a 9V battery and a multimeter) just checked for vids and there are some on youtube The two relays close together are for the solenoids so if your problem is not the gas valve then you have 3 to test. If you find a relay not switching/latching you've got it. De-solder and replace. IF ITS NOT THE RELAY THEN ITS EASIER TO FIND, THIS BOARD IS DIODES, RESISTORS and CAPACITORS on the whole. Just Youtube how to test them A little patience and you might just enjoy it! will go a long way. THERE'S NOTHING ON THESE BOARDS THAT CAN"T BE REPLACED For the relay: Order this relay: Finder 30.22.7.012.0010 https://uk.rs-online.com/web/p/non-l...elays/4926596/ (Make sure its this EXACT code, there's one very similar that only does 1.2A instead of 2A) If your happy to de-solder the relay then bottoms up! your done! if not then..... ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- JUST FIND A LOCAL ELECTRONICS SHOP AND THEY SHOULD DO IT FOR $50 EITHER WAY YOU'VE JUST SAVED A HEAP OF CASH AND LEARN'T SOMETHING! ++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++ ------------------------------ Alternatively - If your uncomfortable with this ------------------------------ Just ring an electronics shop - These boards are simple, cheap non surface mount components. I bet any electronics shop could check through the whole board and replace the part for around $50, DON"T GET FLEECED FOR $400 TO BUY A WHOLE NEW BOARD, I hope this helps others in the future and saves lots of $$$ for people, any questions please just send a message - Feel like i know these boilers rather well now! Actually very simple once you understand them. ++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++ TRUMA BOILER GENERAL TROUBLE SHOOTING TIPS! ++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++ THE SOUNDS OF STARTING UP! -Gas combustion chamber fan starting - a small whirring noise, this is the small fan at the back of the boiler - Main Air Distribution fan, if on AIR heating mode - This is a louder fan that will drown out the Gas chamber fan noise. Fwd of and next too the gas combustion fan. - Gas valve opening noise - NOW this is a loud METALLIC TWANG noise NOT A CLICK! the CLICK! is a relay latching. IF YOUR UNSURE OF THE GAS VALVE PUT YOUR FINGER ON IT AS IT OPENS YOU WILL FEEL THE CLICK. - Igniters sparking - a series of clicking sounds. GENERAL HARDWARE TESTS - Gas chamber combustion fan - Check the outlet, outside the vehicle- is it blowing air. Contrary to popular belief, on other forums there is not air mix register in the boiler! I've CHECKED! so if its blowing its working! Also you can take it off and put it straight to a 12v battery to check operation. - Air distribution fan, same as above, checking the air inlets in the vehicle, or you can physically see this fan work situ, its down the aft side of the boiler near the combustion fan. - Igniter: Put a 12 V battery to it. Its the blue thing fastened to the fwd front leg of the boiler. You'll need to open the chamber to check for sparking. NOT VERY HARD TO DO don't be put off, - Gas valve (My problem) ISOLATE ALL GAS! Undo the gas inlet, and take the valve off. Run up the boiler and blow down the valve. If it opens air will pass through: wink2: If not, take off the solenoids and put something ferrous in them (Anything iron). start the boiler again and see it it moves. If it doesn't create a magnetic field to move the item, its the PCB, and therefore most likely the relay. ----------------------------------------- How the boiler works on demand ----------------------------------------- - The gas fan blows clearing the chamber and supplying air and clearing combustion fumes, after approx 60 secs,one gas valve opens letting the gas in and the igniters, ignite it. Inside the boiler is another metal strip which when hot tells the PCB that a flame is lit. When more demand is required of the boiler it opens the second valve and lets more gas in (The gas valve is actually gas valveS - There are two operated by separate solenoids - It's just integrated into one unit. Common problems it seems, - Combustion fan not running, hence do to gas overload the boiler will not light - Check outlet outside for blowing of air, Check with separate 12v supply to see if it runs. Check PCB Relay. - Boiler runs fine on start up then fails when i turn it up or it requires more heat: Most likely its the second solenoid valve relay! i.e. Check the PCB Relay adjacent to the one i marked in the pictures. ' Could be the physical valve' - Hot air is not distributed to the van. Makes how water fine and not hot air: Most likely the fan on top of the boiler, check with separate 12v supply and if it works check PCB relays - Boiler ignites but then shows red light after a minute or so - The temp sensor in the combustion chamber is not working. - No clicking sound to ignite the boiler - The igniter has failed - the blue unit tied to the leg, OR the Igniter relay on the PCB, check the igniter by putting a separate 12v power supply to it. - Does not ignite, fans working, valve working, igniters sound to be clicking. Open the gas chamber and visually check the igniters. Most likely insulation around the igniters has broken down - Boiler just not starting up, check Leisure batt voltage, most things on the boiler work 12V -20% + 20% - If its cold outside check your using Propane of LNG not Butane, - Low gas pressure due to regulator - Ignite all 3 burners on your stove then start the boiler, it the burners go 'down' a notch and the boiler fails to light it could be the regulator. Ok GODSPEED FELLOW MOTORHOMERS! & hope this helps someone in the future! Please add to the thread if it helped with your problem or you found something else and how you solved it, i bet it won't be long until these PCB prices are SKYHIGH due to stopping of manufacture or just general human greed. If your in doubt with this, again just find a local electronics shop and i bet they can fix your PCB for $50! Unfortunately no one won a pint this time! But if i meet any of you on the road i'll still get you one P.s. Photos, Zoom in 'IMG_20200129' to find the relay with the pencil X on it, this is the primary low demand gas opening solenoid relay, the one right next to it is the high demand gas relay. The last pic is the card back in place. ++++ COULDN'T"T UPLOAD THE PHOTOS, SO I GUESS GOOGLE THE ORIGINAL POSTS IF YOU NEED THEM++++ Link to comment Share on other sites More sharing options...
MarkHymer Posted February 3, 2020 Author Share Posted February 3, 2020 OK hope this helps someone in the future :) Link to comment Share on other sites More sharing options...
Alanb Posted February 3, 2020 Share Posted February 3, 2020 Mark, Many thanks for the detailed post. I only hope that I do not have to make use of it, as it seems that the first step in removing my Truma PCB, would be to remove the complete boiler. When posting photos, basically reduce to 100K. Attach after ticking the appropriate box AND posting. Link to comment Share on other sites More sharing options...
John Allen Posted February 3, 2020 Share Posted February 3, 2020 Mark It's people like you who make this sort of effort and share your knowledge that makes this such a great forum to be a member of. Thanks John Link to comment Share on other sites More sharing options...
witzend Posted February 3, 2020 Share Posted February 3, 2020 MarkHymer - 2020-02-03 7:18 PM OK hope this helps someone in the future :) Many Thanks from me as well for sharing this info hope you have some good trips with the Hymer now Link to comment Share on other sites More sharing options...
Derek Uzzell Posted February 4, 2020 Share Posted February 4, 2020 Mark originally asked for advice about his Hymer motorhome’s boiler on the MotorHomeFacts forum on 20 January 2020. The thread was headed "Thule C3402/ 6002 Boiler Help Needed Please! Pint to be won!” and the discussion in its entirety can be found here https://forums.motorhomefacts.com/220-water-sanitation-heating/237963-thule-c3402-6002-boiler-help-needed-please-pint-won.html Within that thread Mark provided five images, but it will be necessary to register/logon to MHFacts to view them. Fairly large files can be attached to MHFacts postings and all of Mark’s attached images exceeded 400kb in size. As Alanb has said, to attach those images here it would be necessary to reduce their size to 100kb or less. Link to comment Share on other sites More sharing options...
MarkHymer Posted February 4, 2020 Author Share Posted February 4, 2020 Hello again all, didn't expect any replies! Very friendly forum! , To Alanb - No Problem and many thanks Alan. I'll give uploading the pics a go for completeness. The PCB is on the front of the boiler in the black box, easy to get at - You don't need to remove the boiler. If you do- in the HYMER it's only mounted with 3 small bolts, all easy to undo - Its really not hard to pull it out. 15mins work. To John Allen, Many thanks for the good words John, Its always nice to share info and help others as I've been helped in the past. Hopefully get people out of a dilemma! To Witzend, No problem at all Sir, hopefully it comes in handy, and many thanks for the good wishes for further travels! To Derek Uzzell, I'll give uploading the photos here a try, i'll try and find away to reduce them from 400mb to 100mb good spot! Best Regards Mark P.S. I've been renovating the HYMER, completely ripped out and re-did the front from engine up, New soundproofing, made new wood dash, made new carpets, put in USBs, fixed the passenger cupboard, Spray painted all the A/C vents and window trims, painted the walls etc. Also done other jobs - Skylights, plumbing, refitting mirrors in bathroom, got GASLOW fitted, replaced external door catches and lights, Sealing external joints, engine clean etc but the front was the big one. If anyone is interested or wondering about doing the same, i could post some pics with a how i did it, tools, materials, methods etc... Or just drop me a message if your wondering what to expect or help if your already doing it! She's looking like new now (All most! (lol) ) Link to comment Share on other sites More sharing options...
MarkHymer Posted February 4, 2020 Author Share Posted February 4, 2020 Ok worked out how to shrink the photos! Link to comment Share on other sites More sharing options...
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