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Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Ron & Connie Sedgley on December 13, 2010, 10:47:45 am

Title: HELP! - Freezing temps and Diesel heat (Aquahot) does not seem to start!
Post by: Ron & Connie Sedgley on December 13, 2010, 10:47:45 am
I do not seem to be able to get diesel heat to come on. 

Temperatures here in Marietta, GA are now below freezing, forecasted to be so for the next two days, and to go as low as 13oF. I took my MH to storage (covered outdoors) and plugged into 20 Amp 120 volts.  I turned on both electric and diesel heat in anticipation of freezing temps.  Diesel heater started as to augment electric.  Within a minute or so the diesel light went out although the switch was still on.  It seems as if diesel is not igniting but I am not sure.

I recently had my Aquahot serviced for the normal annual service.  All Aquahot systems seemed to be working fine over the last three weeks on the road.

Aquahot Model Number: AHE-100-01S

I have sent a not to Roger Berke and also posted on HydroHot Forum, but post here for FYI and any possible additional insight.
Thanks!
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Paul Smith on December 13, 2010, 10:50:41 am
Turn off electric and diesel might cone on when temp drops
 
Quote from: "Ron Sedgley"
I do not seem to be able to get diesel heat to come on. 
 
Temperatures here in Marietta, GA are now below freezing, forecasted to be so for the next two days, and to go as low as 13oF. I took my MH to storage (covered outdoors) and plugged into 20 Amp 120 volts.  I turned on both electric and diesel heat in anticipation of freezing temps.  Diesel heater started as to augment electric.  Within a minute or so the diesel light went out although the switch was still on.  It seems as if diesel is not igniting but I am not sure.

I recently had my Aquahot serviced for the normal annual service.  All Aquahot systems seemed to be working fine over the last three weeks on the road.
 
Aquahot Model Number: AHE-100-01S

I have sent a not to Roger Berke and also posted on HydroHot Forum, but post here for FYI and any possible additional insight.

Thanks!

Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Michelle on December 13, 2010, 11:14:50 am
Ron,

I don't think you'll be able to run the AH electric element on 20 amp.  That's a pretty big current draw.

Is the diesel just not coming on right after you got to storage, or has it been a while?  Depending on how long it took you to drive there, the fluid could be up to temperature from the driving.

I don't recall seeing the lights on our switches ever going out, even when the AH isn't heating.  Is it possible you tripped a 12V breaker or blew a fuse? 

Just brainstorming until Roger or someone else answers...

Michelle
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Ron & Connie Sedgley on December 13, 2010, 11:31:11 am
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Barry Beam on December 13, 2010, 11:42:29 am
    Thanks for the quick replies!  :)
      • We have been running electric & diesel at this storage facility for the last three years without problem.  The Aquahot has been working fine over the previous three weeks since being serviced.
      • We just moved the Motorhome to storage last Saturday evening and tried to switch diesel and electric upon arrival. 
      • I thought about a 12v circuit breaker problem, but several attempts to switch diesel on resulted in

      • diesel light coming and and diesel attempting to start
      • diesel light going out within a minute or so and diesel eventually turning off

      • I'll try keeping the electric off for a short time while switching diesel on. 


When you turn on the diesel heat, the diesel burner goes into a lighting sequence.  The following things happen in this order.

The blower motor starts, which starts the fuel pump.

The motor runs for about 1 minute to allow fuel pressure to build up and stabilize.

The fuel solenoid opens (spraying fuel into the burning chamber),
the ignition coil starts creating a spark across the electrodes
(igniting the fuel that has been sprayed into the burning chamber).

There is a very slight delay. 
The photocell (that is adjacent to the burning chamber) looks for light from the burning diesel fuel.

If the photocell sees light, everything is good and the burner will continue to run.

If the photocell DOES NOT see light, the fuel solenoid closes and the `diesel' light next to the switch in your coach goes out. The blower continues to run (purge cycle) for about 2-3 minutes to purge unburned diesel (and heat if the unit has been running).

Blower motor shuts down.

As you can see, this is a complicated sequence. If ANY component fails to operate properly, the diesel burner will not operate.

Some things that you can check:

Fuel – The fuel tank pick up line is like the generator, it will not pick up fuel if the tank is less than ¼ full. I have heard of coaches that won't draw diesel if the tank is less than 1/3 – ½ full. You would know your coach better than anyone else if this is the issue.

It could be any of the following items that have failed. Fuel pump, solenoid valve, clogged nozzle, ignition coil (+wires + electrodes), or photocell.  On the older (non electronic control board) Aqua-Hot, the high limit thermostat.
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Ron & Connie Sedgley on December 13, 2010, 11:53:36 am
Thanks Barry --- That is the exact sequence of events that I'm experiencing without the diesel igniting. I am at about 3/8 of a tank.  That may be the problem since I am so close.  I'll go to fill up with some diesel and give it another try.
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Jim Frerichs on December 13, 2010, 12:12:52 pm
Hi Barry,
 
To your list of causes of Aqua Hot problems would you want to add....partial failure of the control box - where typically the heater does not start-up, stay on or shut-down properly. The control box often is the last thought most folks think about when they having heater problems. I am seeing lots of these in my control box repair service.
 
Jim
308-440-5154
 
Quote
It could be any of the following items that have failed. Fuel pump, solenoid valve, clogged nozzle, ignition coil (+wires + electrodes), or photocell.  On the older (non electronic control board) Aqua-Hot,
the high limit thermostat.
 
Barry BEAM  #16014
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Paul Smith on December 13, 2010, 12:20:19 pm
A real 20 amp connection did well for our AH. Electric was too expensive so I switched to diesel.

best, paul

Quote from: "Steve & Michelle"
Ron,
 
I don't think you'll be able to run the AH electric element on 20 amp.  That's a pretty big current draw.

Is the diesel just not coming on right after you got to storage, or has it been a while?  Depending on how long it took you to drive there, the fluid could be up to temperature from the driving.
 
I don't recall seeing the lights on our switches ever going out, even when the AH isn't heating.  Is it possible you tripped a 12V breaker or blew a fuse?
 
Just brainstorming until Roger or someone else answers...

Michelle
 
'03 U320 40' coach 6106
'03 Honda CR-V
and the Posse

Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Brad on December 13, 2010, 01:39:12 pm
Ron,
If the diesel still does not work after you fill your tank you might check the AH fuel lines going to and from the Racor fuel filter.  I had a leak in the fuel lines as they made the bend into the fuel filter.  You usually have some white smoke from the exhaust before the burner cuts off and then the inside diesel light goes out.

Good luck and stay warm,
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Barry Beam on December 13, 2010, 02:10:45 pm
Thanks Barry --- That is the exact sequence of events that I'm experiencing without the diesel igniting. I am at about 3/8 of a tank.  That may be the problem since I am so close.  I'll go to fill up with some diesel and give it another try.
Some time back Roger Berke told me to check for cracked fuel lines.

"Upon tracking down the fuel lines I found that the fuel lines that connected to the fuel filter had dried out and cracked, leaking air (no fuel).  I found that Foretravel had used 1/2" barbed fittings with 7/16" fuel hose.  You can  see in the photo below (or attached) that the fuel line on the 1/2" barbed fitting is 'bulged out".  the proper fitting (7/16") is on the right.  This fitting shown in the photo is the assembly that feeds the fuel through the lower box of the Aqua-Hot unit.  It has failed also (you can't tell from the photos, but the hose is cracked .... leaking air).  I have the fuel supply hose connected direct to the burner head with a straight through barbed fitting."

Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Ron & Connie Sedgley on December 13, 2010, 03:12:36 pm
 :) :) :) What a Team!!!  :) :) :)

I had previously thought that my fuel tank was between 3/8 & 1/2 full.  When I got back to the MH it was really between 1/4 & 3/8!  After quick trip to the fuel farm adding some diesel (30 gallons) and Voilà... a big long puff of white smoke and we have diesel heat!  Thanks to all.  I think when my contract is up I'm going to enforce my 'No Trade" clause.  What a team.  Particular thanks to you, Barry for zeroing in on the possible cause. 

FWIW.... It got down to 24o here in Marietta last night.  My remote sensor on my thermometer in the Service bay recorded a minimum of only 35o last night with just the electric on.  However, I did additionally have a 100W bulb lit in the bay next to the water service center as a minimum extra precaution. If we had lost power (as several areas did) last night I would have been up the creek.  The forecast for this evening is between 12o and 17o in the Atlanta Metro area.

This "event" also got me to think... What do you do if you are driving any distance in sub freezing weather?  What keeps the bays warm?

Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Barry Beam on December 13, 2010, 03:25:05 pm
:) :) :) What a Team!!!  :) :) :)

I had previously thought that my fuel tank was between 3/8 & 1/2 full.  When I got back to the MH it was really between 1/4 & 3/8!  After quick trip to the fuel farm adding some diesel (30 gallons) and Voilà... a big long puff of white smoke and we have diesel heat!  Thanks to all.  I think when my contract is up I'm going to enforce my 'No Trade" clause.  What a team.  Particular thanks to you, Barry for zeroing in on the possible cause. 
This "event" also got me to think... What do you do if you are driving any distance in sub freezing weather?  What keeps the bays warm?
    • I have my thermostat in the bath is on
    • but the main heater thermostat is typically off
    • Will the bays still remain warm from engine heat circulation?

Yes your engine will circulate the heat thru the Aquahot to heat the bay.  8)
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Ron & Connie Sedgley on December 13, 2010, 03:29:56 pm
Thanks Barry!  ;)
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: wolfe10 on December 13, 2010, 03:40:44 pm
Ron,

It is much better to store your coach with the fuel tank FULL.  This minimizes condensation in the fuel tank. And having water condense in the fuel tank leads to all kinds of contamination issues.

Brett
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Ron & Connie Sedgley on December 13, 2010, 03:45:25 pm
FWIW.... It got down to 24o here in Marietta last night. 
Correction... It got down to 19o here at my home 25 miles north of Atlanta.
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Bob McGee on December 13, 2010, 04:35:04 pm
Quote
This "event" also got me to think... What do you do if you are driving any distance in sub freezing weather?  What keeps the bays warm?

•I have my thermostat in the bath is on
•but the main heater thermostat is typically off
•Will the bays still remain warm from engine heat circulation

Ron,

Your bay circulation is independent of the interior thermostat settings for your furnace zones, including the bathroom. There is a separate thermostat in your plumbing bay for this. Check the setting on this to be sure it is high enough. I keep mine at 38 degrees.
Assuming the Aquahot is being heated by either diesel, the electric element, or the engine, the zone 2 (bathroom) circulating pump will provide hot coolant and a fan will ciculate the warm air.
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Ron & Connie Sedgley on December 13, 2010, 04:36:22 pm
Thanks Brett --- Hopefully this is not going to be a long term storage.  We hope to be going out again over Christmas or early next year.  I do not always keep my tank full, though (watching for Diesel price fluctuations).  Are you saying that you should never park for any length of time with less than a full tank?
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Ron & Connie Sedgley on December 13, 2010, 04:45:44 pm
Ron,

Your bay circulation is independent of the interior thermostat settings for your furnace zones, including the bathroom. There is a separate thermostat in your plumbing bay for this. Check the setting on this to be sure it is high enough. I keep mine at 38 degrees.
Assuming the Aquahot is being heated by either diesel, the electric element, or the engine, the zone 2 (bathroom) circulating pump will provide hot coolant and a fan will circulate the warm air.

Thanks Bob... My Thermostat in the Water Service (Plumbing) compartment is set at 42o.  I was aware that the zone 2 (Bathroom) circulation pump would provide coolant circulation and the bay fan would circulate the air as long as the thermostat in the bathroom was set 'ON'.  I was just unsure what heated the coolant while on the road in sub freezing temps. 
 ::)  I think that I just thought through the answer to my question (with the team's help).  ::)
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: wolfe10 on December 13, 2010, 04:46:02 pm
Thanks Brett.  Are you saying that you should never park for any length of time with less than a full tank?

That is correct.

 Example: If you have a 100 gallon tank and drove 3/4 of that out early this fall (when you had high temperatures and high humidity in GA) you now have 25 gallons of fuel and 75 gallons of humid air-- probably with a dew point of over 65 degrees F.  When the walls of the tank get below that temperature, water starts to condense and sinks to the bottom of the tank.  When it gets down below freezing a LOT of moisture will condense in the tank.

Additionally, as the tank breathes (remember, there is a vent line, it is not sealed) air out during the day (hot air expands) and air in during the night, additional moisture is drawn in.  To then condense.....

The few dollars you may save speculating on the price of diesel will appear very small if you end up with injector issues or algae growth in the diesel (the algae grows at the water/diesel interface).

Brett
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Peter & Beth on December 13, 2010, 04:49:04 pm
Thanks Brett --- Hopefully this is not going to be a long term storage.  We hope to be going out again over Christmas or early next year.  I do not always keep my tank full, though (watching for Diesel price fluctuations).  Are you saying that you should never park for any length of time with less than a full tank?
My 2 cents as follows:
Condensation inside the fuel tank is a function of the temperature differential (gradient) between the fuel temperature and the ambient temperature inside the tank.  After having driven for a long time, the fuel temperaure will rise proportionatelly with the amount of fuel left in the tank.  Said another way, the lower the fuel level in the tank the higher the likelihood that the fuel temperature increase is much higher.  (The above due to preheated fuel being returned to the tank).
 
In colder climates condensation could be even greater due to the increased temperature gradient between fuel & air temperature.
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: George Stoltz on December 13, 2010, 04:50:22 pm
Ron,
 
I would not and do not.  If we are going to be parked for more than a week, we do so with a full tank or at least well above the 3/4 mark.  We are very careful about this.
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Ron & Connie Sedgley on December 13, 2010, 06:09:00 pm
Thanks again to all... Back to the fuel farm again for me..  :)
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Bob McGee on December 13, 2010, 07:37:22 pm
Quote
I was aware that the zone 2 (Bathroom) circulation pump would provide coolant circulation and the bay fan would circulate the air as long as the thermostat in the bathroom was set 'ON'.


Ron,

On my coach the bathroom thermostat does not have to be on for the bay heat to operate. The bay thermostat is independent of the bathroom thermostat.
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Roger Berke on December 13, 2010, 09:37:37 pm
The bay heater has its own thermostat.  Recommended setting about 40 degrees.  When the thermostat calls for heat in the bay, the circulation pump starts along with the fan in the bay.

The bay heater is independent of heaters inside coach.

Your Aqua-Hot needs to be warm (diesel or electric) to get heat in the bay.

- Roger Berke -
2000 Foretravel U320 42ft
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: Roger Berke on December 13, 2010, 09:52:27 pm
Some time back Roger Berke told me to check for cracked fuel lines.

"Upon tracking down the fuel lines I found that the fuel lines that connected to the fuel filter had dried out and cracked, leaking air (no fuel).  I found that Foretravel had used 1/2" barbed fittings with 7/16" fuel hose.  You can  see in the photo below (or attached) that the fuel line on the 1/2" barbed fitting is 'bulged out".  the proper fitting (7/16") is on the right.  This fitting shown in the photo is the assembly that feeds the fuel through the lower box of the Aqua-Hot unit.  It has failed also (you can't tell from the photos, but the hose is cracked .... leaking air).  I have the fuel supply hose connected direct to the burner head with a straight through barbed fitting."


I believe that this fuel line problem involves 1999 models sometime AFTER coach build 5513, all of the 2000 models and some of the 2001 models.  I am still trying to narrow down which coaches are affected.

- Roger Berke -
2000 Foretravel U320 42ft
Title: Re: HELP! - Freezing temps and Diesel heat does not seem to start!
Post by: George Stoltz on December 13, 2010, 10:00:26 pm
Roger identified this problem on our 2000, shipped the correct size fittings to me and I had them installed by a tech who has more strength in his arms than do I.  This is not an easy fix. Had I started it, I would not have been able to complete it. 
Title: Re: HELP! - Freezing temps and Diesel heat (Aquahot) does not seem to start!
Post by: amos.harrison on December 14, 2010, 12:47:22 am
Another important issue not raised here is diesel fuel formulation.  If you store your coach with summer fuel, and then expect to drive it in winter, you will likely encounter fuel gelling problems.  You should add an anti-gelling additive before topping up your tank for storage.  The same risk occurs if driving north in the spring to freezing temperatures using southern fuel.  It's much better to fuel up in the colder area rather than buying perhaps cheaper fuel in the south.