Aqua Hot new boiler install

[96 EVO]

I'm assuming fuel pressure at the nozzle, and even a single spark, rules out any bad sensors in the rebuilt tank?

[Guest Ray Davis]

On 3/25/2023 at 11:15 AM, vito.a said:

Yes.  I purchased the new boiler assembly from John Carrillo.  A few years ago when my ignition coil failed, he was very helpful.  However, he has been less than helpful this time. 

John Carrillo- Heat My RV

7800 Miller Dr Unit C, Frederick, CO 80504

Phone: (970) 518-3085

 

Sorry about that Vito, I don't know Carillo never met or done business with him.  Maybe he was having a bad day.

On 3/25/2023 at 9:24 PM, pwhittle said:

I love your posts Vito!

So much information for the other members to benefit from.

Thx Mate.

Paul

Amen Paul,  I always wonder,   how Vito knows so much about Monacos.

1 hour ago, Ivan K said:

I had to replace the AH igniter once. As I remember, the coil is supposed to repeatedly spark until a flame is detected or the flame detection times out. That, outside of a typical RV upcharge, makes it more expensive than home heating AC coils because it needs electronics to simulate a trigger. Not as simple as some automotive coils. Still way too expensive. Like $300 vs $45 in my shop heater last time I replaced both of mine.

Yep mine would spark repeatedly,  it reminded me of an old Ford Model T ign. coil only it's not 12v.  I bet that an old Ford coil could be made to work, temporarily.

[96 EVO]

10 minutes ago, Ray Davis said:

Sorry about that Vito, I don't know Carillo never met or done business with him.  Maybe he was having a bad day.

 

I've never received a reply from him from when I tried contacting him thru his website, back in Dec.

[vito.a]

Attached is a picture of the bottom of the old style boiler.  This style has the copper pipes wrapped around the outside of the boiler.  The copper pipes near the exhaust port are exposed to outside air because the hole in the floor is larger than the exhaust port.  In freezing weather this can be a disaster even with a heater in the bay.  

The picture is turned sideways, so the bottom of the boiler is on the left.  

[96 EVO]

Does your new tank have the internal fresh water coil?

[vito.a]

Yes, it does.  And at least on AC electric, it seems much better.  The hot water is truly hot even in 30-degree weather.  

[k7jv]

I absolutely agree with the one comment above about the flame sensor.  I am pretty sure that the ignition continues to spark, repeatedly, until it either times out or a flame is sensed.  The start-up process would begin with fuel and air being admitted and sparking initiated.  If, after the first spark, the resistance at the photo cell is low, it will be seen as a flame present, and further ignition would be stopped.  Vito, I am going to be very surprised if you don't have it nailed, now!  Yay!!!!  Fantastic project, super craftsmanship, way more than I would have been willing to tackle and a great success story in the end!!!

[Discover 17]

I have following along and hope you have found the problem. If not I have attached some information by My RV Works, a tech out of Washington state. Here is a link to his You Tube channel. I hope this will help you if you are still in need. https://www.youtube.com/@MyRVWorks/search?query=Aqua Hot

 

[DZZippy]

Hi all. I have been doing a bunch of work on my AquaHot lately. I’ve recently replaced supply and return lines, adjusted fuel pump pressure, on top of the annual maintenance items. All this because it was smoking extensively. I only mention this as I have done the same with drilling and taping an old nozzle to complete this. I have learned a few things in the process not described in the tech / shop manual or any videos. My intention is only to try and help and not muddy the water any more.

a few things to note….when you saw the single spark and saw the rise of fuel pressure…did the unit (fuel pump and fan) continue to run until you shut down the unit? Did it shut down immediately with no timed run to simulate cool down? Asking because a few things I noticed…if the flame sensor is exposed to light it should trick to think the system is running with flame and continue to run until you shut it down. However, if it is exposed to too much light before the ignition process it gets very confused.  I did have a situation that I had too much light when going to adjust, got a single spark and the whole unit shut down. If I made the surrounding environment darker ….it continued to spark until I had a flashlight over the flame sensor to simulate light and then ran with gauge installed with no issues. The 60ohms seems a bit off but I would have to pull the specs out of the shop manual. The manual specifies ohms both exposed to and not exposed to light.

 

keep up the great work!

Edited March 30, 2023 by DZZippy

[Guest Ray Davis]

Good point about light striking the flame sensor.   I'll mention that the flame sensor should be wiped off with each service so it doesn't become blind.

[gjh2916]

Vito I replaced my tank with a new style from John Carrillo a couple of years ago, and after the install it would not fire. Igniter worked it was like it wasn't getting fuel. John was very helpful with my problem. Finally after numerous diagnostic procedures, We determined it was the fuel solenoid, I purchased Fuel Solenoid kit WPX 386650 from John and that solved my problem. Their is no correlation between changing the tank and the fuel system, just a coincidence solenoid stop working best I can figure. That was almost three years ago and AquaHot is still working fine today.

[vito.a]

I made some progress!  I replaced the flame sensor and the diesel burner ignited.  I cheered loudly!  However, it was smoking badly so I shut it down and checked everything.  I removed the diesel pump and one of the rubber grommets was out of place.  I put it back into the notch and reinstalled the diesel pump.  I started it again and the smoke is better, but still not as good as it used to be.  I may need to remove the pump again and see why it’s not seating all the way.  The diesel pump just doesn't fit this boiler opening as snug as it fit the original.  

I think the flame sensor sitting in sunlight for a few days while I overhauled the unit caused it to fail (it may have been on it last legs anyway).  It read 60 ohms light or dark.  The specs are 300 ohms or less when exposed to light, and 300,000 ohms or more when dark.  The flame sensor is one of the easy parts to replace.  Just 1 Phillips screw holds it to the burner plate.  

My zone 2 and 3 pumps come on so I think the wiring is good.  However, they have lost their prime.  These older pumps are situated at the top of the unit and require priming by applying air pressure to the boiler.  I am making up a short heater hose to attach to the boiler fill port (this boiler doesn’t have a radiator cap)  with a Schrader valve so I can pressurize the tank. 

I'll order the Schrader valve and hose adapter.  

I think I'm getting closer if I can figure out the smoking issue.  

[96 EVO]

Any way of making a gasket to give the burner a better seal?

Air being sucked in there could be causing the smoke.

 

Edited March 31, 2023 by 96 EVO

[vito.a]

Discovery 17, I saw some of the My RV Works videos.   He's a great teacher with lots of patience.  

Gary, I was thinking I had a bad fuel solenoid also, but it's working okay for now.  

Ben, good idea about the seal.  It would have to be heat resistant.

I'm now thinking the smoking is caused because the photo disc is warped.  The round metal plate the flame sensor mounts to is called the photo disc.  The photo disc should provide the seal against the combustion chamber, not the pump assembly.  

I'm learning, some of it the hard way.  

[96 EVO]

Vito, you probably know this, but the photo disk to needs to 'float'!

I watched one youtube clip where the guy was shimming it up with washers, cause he didn't think it should be loose!

 

[gjh2916]

Vito

I had to force bleed my system after I installed a new tank air was getting trapped in some of the zones.

[vito.a]

Gary, did you force boiler fluid through the zones one at a time, or all three together?

[gjh2916]

19 hours ago, vito.a said:

Gary, did you force boiler fluid through the zones one at a time, or all three together?

One at a time with an external pump. I used a drill pump same one I use to change oil in my boat.

[vito.a]

I replaced the round metal "photo disc" on the front of the diesel burner and reinstalled it.  Now the diesel burner will not run.  It's very quiet.  I removed it again and  tested fuel pressure.  It's not getting any fuel or blowing air.  But, the spark works continuously.  

Initially i thought it was something I had done wrong.  I spent some time troubleshooting and could not find any misplaced wires. 

This time after removal I could hear pieces rattle when I turn it over.  I'm pretty sure the clutch is broken.  

I thought about this overnight and decided to send the diesel burner in for rebuild.  

[96 EVO]

Wow!

When it rains it pours!

[vito.a]

Below is a picture of my fuel pressure gauge fitted into an old nozzle as well as a Schrader valve attached to a 5/8" heater hose.  

Zone bleeding procedure:  I turned off both boiler fluid ball valves (the upper goes out to the house heat exchangers and the lower is a return back to the tank).  Then attach the heater hose/Schrader valve adapter to the boiler tank overflow and pressurize it with 15psi from an air compressor.  I then went inside and set the thermostat to Furnace-Zone 3 and turned the temp up to 85.  Then open the upper ball valve allowing fluid out of the boiler into the house heat exchangers.  Next open the drain valve at the bottom of the Aqua Hot.  You can hear the loud air pockets as they blow out the drain valve.  I did this twice for each zone.  I may have to do Zone 1 again as it goes through the kitchen and living room all the way to the front of the coach.  

The caution here is not to let the boiler tank fluid level drop too low or it will blow air out into the heat exchangers.  I had to refill the tank after each zone.  Also, you do not necessarily need the boiler up to temperature.  

The bolt in the picture is used to plug the overflow hose from the overflow tank.  

Also attached is a picture of the new overflow tank.  It's mounted to the wall in the basement compartment just in front of the Aqua Hot.  The hose from the overflow tank goes up through the plywood ceiling cover and back to the Aqua Hot (picture is sideways).

Edited April 7, 2023 by vito.a

[Ivan K]

Nice that you got it figured out. I found it bit strange that I did not have to do any of the bleeding after reinstalling our system but suppose it was because the pumps got primed when the coolant expanded with temperature. Since then, I eliminated the pressure cap so it just freely expands into its expansion tank and that could be the reason for having to bleed it.

[gjh2916]

6 hours ago, vito.a said:

I replaced the round metal "photo disc" on the front of the diesel burner and reinstalled it.  Now the diesel burner will not run.  It's very quiet.  I removed it again and  tested fuel pressure.  It's not getting any fuel or blowing air.  But, the spark works continuously.  

Initially i thought it was something I had done wrong.  I spent some time troubleshooting and could not find any misplaced wires. 

This time after removal I could hear pieces rattle when I turn it over.  I'm pretty sure the clutch is broken.  

I thought about this overnight and decided to send the diesel burner in for rebuild.  

Vito the spark should only run for about 15 seconds. Do you have a copy of the AquaHot service manual?

Vito

Attached is copy of parts manual and Service Manual hope these can help

AHE-100-02S Service Manual Rev. B 9-27-2011.pdf AHE-100-02S_Parts_Manuals_Rev_B.pdf

[vito.a]

Okay. Thanks. 

When the flame sensor is bad you only get 1 or 2 sparks. 

I'm not sure what caused no fuel pressure initially and then started working. 

I'm also not sure why the clutch suddenly broke. I guess just bad timing.  

The diesel burner was due for a rebuild.  

[On_the_road]

When I tested the spark on my burner, I would only get 1 short spark.   Then I realized that my work light was hitting the sensor.   I put a piece of black tape over the sensor, then the spark worked as I would have expected.   You might want to try that.