AH not working on diesel

Topic: AH not working on diesel (Read 1275 times) previous topic - next topic

AH not working on diesel

November 24, 2023, 12:34:24 pm

Woke up to a cold coach this morning with AH blowing cold air. Outside temp 41 degrees and AH not up to temp (electric element on but couldn't keep up)>

When diesel switch is turned on, the light goes off in approx 20 seconds. In those 20 seconds no pump (correction, motor insde burner case) running as usual.

What I have done so far is removed cover over AH, checked that 12 volt (13.4) is good and checked all the 12 volt fuses including for continuity, and checked top left thermostat for continuity (should be the VDC control thermostat). Edit: also checked bottom left thermostat for continiuty.

Trubleshooting AH manual SECTION 8: DIESEL-BURNER COMPONENTS/TROUBLE SHOOTING said those were first steps.

Re: AH not working on diesel

Reply #1 – November 24, 2023, 12:39:18 pm

Wait for Rudy to reply but sounds like the controller to me. I always carry a spare and can switch quickly to see if that fixes the issue before going to more serious trouble shooting.

Re: AH not working on diesel

Reply #2 – November 24, 2023, 01:06:18 pm

Quote from: craneman – November 24, 2023, 12:39:18 pm

Wait for Rudy to reply but sounds like the controller to me. I always carry a spare and can switch quickly to see if that fixes the issue before going to more serious trouble shooting.

I'll be calling Rudy.

AH last serviced 2 years ago Nov 2021, but with the pump (correction, motor inside burner case) not running at all before light goes out it shouldn't be a soot or carbon issue. The controller was replaced with a rebuilt from Rudy July of 2018.

Re: AH not working on diesel

Reply #3 – November 24, 2023, 01:12:36 pm

5 years out of an aluminum one is a long life.

Re: AH not working on diesel

Reply #4 – November 24, 2023, 03:54:16 pm

Quote from: craneman – November 24, 2023, 01:12:36 pm

5 years out of an aluminum one is a long life.

Yep, you probably just need to get the new style. Should be better anyway.

Re: AH not working on diesel

Reply #5 – November 24, 2023, 05:31:03 pm

Problem resolved. The reason the diesel would not fire was the motor inside the case of the burner assembly was not working.

Without Rudy's guidance on the phone multiple times I wouldnt have been able to disasemble the burner assembly this far. The burner has to be removed, the outer case has to come off, the coil has to come off. Multiple wires to unplug. Tests with small plug on the controller off, then switch AH on and replug the controller to check motor.

Nothing was replaced. The clutch assembly and the motor looked good, and connecting the motor directly to a 12 volt source it worked fine.

Best guess corroded connector or pinched wire.

Update Edit: Bad motor, intermittent, has dead spots depending on where it stops after last run.

Since I had it all apart I cleaned the burner and put a new fuel nozzle in.

Hit all connections inside burner case and to motor with contact cleaner.

Re: AH not working on diesel

Reply #6 – November 24, 2023, 06:45:54 pm

When servicing the AH I was going to move the tempering valve both ways as oten advised. I got about 1/8 turn when the handle sheared off.

When replacing the tempering valve is all water drained from system first?

Pics from before service, and of sheared valve. Also pic of motor and clutch inside burner case.

Re: AH not working on diesel

Reply #7 – November 24, 2023, 08:31:57 pm

You only need to have the fresh water turned off so that there is no pressure on the water. You don't drain the aqua hot tank.

Re: AH not working on diesel

Reply #8 – November 25, 2023, 12:11:01 am

Dan funny I had the same problem this morning, here in Oklahoma City where it got down to 30°. It wasn't too bad and the coach showing a internal temp said it was 60 so the electric element was doing a fairly decent job of keeping me warm. Once it warmed up enough I pulled everything back out and when I pulled the burner off found that the photo sensor was sooted up. I cleaned everything up pulled the burner out and everything was carbonized which I expected after replacing the wiring. Brushed it all out cleaned it up put everything together and when I fired it up nothing happened. I'm sitting there scratching my head and then I realize that maybe I should call for heat so I turned all the thermostats up and the burner came on blue white smoke for a little while and then settled down. Oh by the way I had a stripped bolt on the side facing me and had ordered a new one and replace it which was kind of fun. I used a Bosch multi-oscalating tool with a very small blade to remove the old bolt. About 8 minutes per side the boat was out I put the new one in and all was good. Sitting inside right now and it's in the high 30s going into the twenties tonight here and I'm toasty warm. Hopefully this system should last again for quite a while. One of the things I really like about working on this system is how much you learn about it. Aquahot has a really good troubleshooting algorithm. And there's always Rudy who as we all know is a wealth of info. Glad you got it figured out. My system's 23 years old so with the new wire harness installed new grommets and now a new t-bolt to hold it down, hopefully it will last for a while. Of course I put a new racor fuel filter in, and nozzle. I also replaced my bearings as one of them was bad.
Nice to be warm, no?

Re: AH not working on diesel

Reply #9 – November 25, 2023, 08:34:11 am

It looks like the repair kit for the tempering valve won't include a fix for the sheared off adjustmant knob: Watts 1/2 in. to 3/4 in. Repair Kit for Lead-Free Tempering Valve - Amazon.com

So I think I will order the entire valve, then transfer the parts: https://www.grainger.com/product/WATTS-Mixing-Valve-LF70A-26X141?opr=ILOF

https://www.zoro.com/watts-mixing-valve-lead-free-brass-12-lf70a-f/i/G4531082/?gclid=f997618785fb13be6bb304e678982767&gclsrc=3p.ds&msclkid=f997618785fb13be6bb304e678982767&utm_source=bing&utm_medium=cpc&utm_campaign=ml_all_dyn_na_ssc_Bing%20core&utm_term=4585788126739859&utm_content=Core

And I may not actually fix it until next time it needs service, just have the parts on hand. Current inside water temp is good at both sinks and at shower.

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Re: AH not working on diesel

Reply #10 – November 25, 2023, 12:39:04 pm

That's what I did, bought the whole valve then swapped out the internal parts. Easy peazy!

Re: AH not working on diesel

Reply #11 – November 25, 2023, 06:06:45 pm

Dave
You mentioned the "new style" controller. Can you explain please. I have the black controller and have seen the silver ones. Also heard the silver one is solid state which I don't know.
Attached pic of my controller

Re: AH not working on diesel

Reply #12 – November 25, 2023, 06:30:42 pm

Peter you have the short lived replacement before Aqua Hot began making their own. The new ones are supposed to be trouble free. The aluminum ones had capacitors that failed frequently. I bought mine from Rudy.

Aqua Hot Webasto Controller — Hydronic Heating Warehouse

Re: AH not working on diesel

Reply #13 – November 25, 2023, 06:56:51 pm

Ok craneman. Is the unit any good?

Re: AH not working on diesel

Reply #14 – November 25, 2023, 07:06:24 pm

No problems so far and last I checked Rudy hadn't had any failures of the new one. It comes with instructions explaining the reason the light doesn't come on immediately. It checks all the components and if all is good the light comes on.

Re: AH not working on diesel

Reply #15 – November 25, 2023, 08:17:06 pm

Quote from: Peter – November 25, 2023, 06:06:45 pm

Dave
You mentioned the "new style" controller. Can you explain please. I have the black controller and have seen the silver ones. Also heard the silver one is solid state which I don't know.
Attached pic of my controller

Peter I had one of these( Still have it) and I was so proud when I found it but it only lasted about a year-- I finally figured out what to do to my old one and repaired it it's been working since been a couple of years
Chris

Re: AH not working on diesel

Reply #16 – November 25, 2023, 08:39:19 pm

I purchased the new controller from Rudy when we were in Yellowstone NP a few years ago! Knock on my head, it is still good to go! No issues! Then Chris fixed me up with the new and improved version of the silver one and I have it as a standby! Thank you again Chris!

Re: AH not working on diesel

Reply #17 – November 26, 2023, 09:45:16 am

Update: Problem still exists. Intermittent.

Temporary solution with outer metal cover off of the AH:

When it fails due to motor inside burner case not starting up.: when diesel switch inside the coach is first turned on, use a rubber mallet and tap on outer plastic burner case to break the motor inside the case loose and it starts running (has to be within 20 seconds or so). Can pull the smaller plug on the controller case and then plug it back in to re-start the 20 second (approx) window of tapping on the case.

Motor has flat spot now. AH will fire and motor works fine until motor stops on dead spot, which is not every time. Then tapping on case moves motor enough to restart.

Permanent solution: Need new motor, just ordered it from Rudy. Since I will have to dis-assemble outer case to replace the motor, I also ordered new clutches to replace at the same time. I figure time and heat may have degraded the clutches even though they looked fine when I had it apart 2 days ago.

It was a steep learning curve over the past 2 days, since I had never even serviced the AH myself before with new nozzle and cleaning combustion deposits (I had hired it out before).

Rudy walked me through troubleshooting via phone, and I searched hundreds of old forum posts. I now have a much better understanding of the system. I did cut and pastes from old forum posts to compile a bunch of information in a word document on the AH systems and troubleshooting.

Rudy is a amazing asset for the Foretravel community.

Re: AH not working on diesel

Reply #18 – November 26, 2023, 05:03:21 pm

Quote from: AC7880 – November 26, 2023, 09:45:16 am

Update: Problem still exists. Intermittent.

Temporary solution with outer metal cover off of the AH:

When it fails due to motor inside burner case not starting up.: when diesel switch inside the coach is first turned on, use a rubber mallet and tap on outer plastic burner case to break the motor inside the case loose and it starts running (has to be within 20 seconds or so). Can pull the smaller plug on the controller case and then plug it back in to re-start the 20 second (approx) window of tapping on the case.

Motor has flat spot now. AH will fire and motor works fine until motor stops on dead spot, which is not every time. Then tapping on case moves motor enough to restart.

Permanent solution: Need new motor, just ordered it from Rudy. Since I will have to dis-assemble outer case to replace the motor, I also ordered new clutches to replace at the same time. I figure time and heat may have degraded the clutches even though they looked fine when I had it apart 2 days ago.

It was a steep learning curve over the past 2 days, since I had never even serviced the AH myself before with new nozzle and cleaning combustion deposits (I had hired it out before).

Rudy walked me through troubleshooting via phone, and I searched hundreds of old forum posts. I now have a much better understanding of the system. I did cut and pastes from old forum posts to compile a bunch of information in a word document on the AH systems and troubleshooting.

Rudy is a amazing asset for the Foretravel community.

While you got it apart you may consider replacing the bearings to...

Keith

Re: AH not working on diesel

Reply #19 – November 26, 2023, 06:34:55 pm

Good thing I did expedited shipping ($$). Can no longer get motor inside case to turn/start by tapping (banging) on burner case. Dead in water for diesel burn.

Low 39 tonight, 37 tomorrow night. Both ACs have heat pumps and we have two ceramic electric heaters, so we will be fine until parts arrive.

Re: AH not working on diesel

Reply #20 – November 26, 2023, 07:48:42 pm

Quote from: Peter – November 25, 2023, 06:06:45 pm

Dave
You mentioned the "new style" controller. Can you explain please. I have the black controller and have seen the silver ones. Also heard the silver one is solid state which I don't know.
Attached pic of my controller

Here's a pic of the grey controller that I got from Rudy last year. I had (still have for possible backup) the black box.

Re: AH not working on diesel

Reply #21 – November 26, 2023, 08:13:12 pm

Quote from: AC7880 – November 26, 2023, 06:34:55 pm

Just have to time showers 2 hours or more apart and watch hot water usage at sinks.

Run the pump and get water from your storage tank. Should be warmer then shore water.

Re: AH not working on diesel

Reply #22 – November 27, 2023, 02:01:00 pm

I second the bearing replacement since you are pulling it out and it's easy to replace them. Removing the cover can be a bit of an issue. You might want to also purchase the o-ring that goes around and seals.
The cover is a type of plastic and could be easily broken. I used a very small flat screwdriver to help release it from the aluminum housing. If you're wiring harness is in rough shape like mine was you might want to think about also replacing that while you're at it although you could just splice new wires in.
I purchased the whole rebuild kit from eBay john carillo I think it was, and the wiring harness from another ebayer. Fun times no?
Yeah those heat pumps don't do anything below 45°. I'm really glad I got my aqua Hot repair before I got on the road as I was going to wait till I got to quartzsite to do it. It went down to 33 degrees last night here I don't think I would have been too happy with that choice.

Re: AH not working on diesel

Reply #23 – November 27, 2023, 09:56:54 pm

I express shipped motor and clutches from Rudy, they will be here tomorrow. I did not order the bearings.

To save time tomorrow, today I disassembled case and motor. Spun the clutch to upper burner with motor removed, bearings (and fuel pump with it) seem smooth and stable.

I tested the motor multiple times on my Jeep battery. Runs smooth when it runs, but definetly intermittent flat spots where it will not start without pushing the clutch a little to break it loose.

Since I had the outer case and motor off a few days ago, disassembly was quick and easy this time. Serviced everything while apart (carbon deposits, fuel nozzle).

Murphy struck while all this is going on. AH 110 volt electric element is burned out. Have 110 volt power right at the element, so breaker, switch, and thermostats are ok calling for heat at element. AH is dead cold. No diesel heat, no electric element heat.

Warm enough for heat pumps and we have 2 small ceramic heaters. Should be up and running on diesel tomorrow, and Rudy will ship a electric element to me.

Re: AH not working on diesel

Reply #24 – November 28, 2023, 08:55:57 am

That's pretty tough, Dan. Hope you get it worked out.
Brenda and I are in Gallup, 8 degrees- burning diesel in our unit. When they work, they are great.

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