where_the_heffalump_roams 917 AF
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where_the_heffalump_roams
Active member
I’m also wondering if that would push the problem back. Meaning whatever is causing air to get in the line would just continue to create that problem, not Jair before the valve?
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where_the_heffalump_roams
Active member
The only part that hasn't been swapped out is the fuel line from the tank > filter and the electric harness.
I did find some diesel at the outlet side of the filter though. Not enough to make it drip and it's probably evaporating. But I'm wondering if that is the source. On paper, I am using the correct sized line, but it does seem a tad too big.
I did find some diesel at the outlet side of the filter though. Not enough to make it drip and it's probably evaporating. But I'm wondering if that is the source. On paper, I am using the correct sized line, but it does seem a tad too big.
where_the_heffalump_roams
Active member
Been playing with the fuel line that goes from the fuel filter to the fuel pump these past couple of days. Woke up to 15C at 2 am and found more air in the filter. Once I disconnected the line and siphoned fuel, it fired right back up. So later that day I bought a new line with a 5/16th/4mm internal diameter and I'm hoping that helps. I'm not sure if I can go smaller with the fuel filter. The local shop didn't have a one way valve.
Along these lines, I'm somewhat confident I spend more time in cold weather vs the prior owners since I snowboard frequently. The currently system works really hard to keep the habitat warm in freezing temps and can't really keep it above 22C when the temps really drop. As I'm going into my 3rd winter in the heffalump, I'm really considering adding another heat system. Something like a Webasto Air top or an Esppar equivalent. I really like the constant, heat of the current radiator style system, but it takes a long time to recover and it pretty much pushes the Webasto to run 24 hours a day at freezing temps. I think it's being used far past it's design.
Anyone else running 2 heaters? If so, are you running them off a single thermostat or two? @Joe917, do you have any thoughts on this? If I go this route, I'd likely go with an external mounted option. The only places I can think of where I can route an inlet/outlet is in the current "dog room" or in the shoe cabinet and use the space where the extinguishers are.
Along these lines, I'm somewhat confident I spend more time in cold weather vs the prior owners since I snowboard frequently. The currently system works really hard to keep the habitat warm in freezing temps and can't really keep it above 22C when the temps really drop. As I'm going into my 3rd winter in the heffalump, I'm really considering adding another heat system. Something like a Webasto Air top or an Esppar equivalent. I really like the constant, heat of the current radiator style system, but it takes a long time to recover and it pretty much pushes the Webasto to run 24 hours a day at freezing temps. I think it's being used far past it's design.
Anyone else running 2 heaters? If so, are you running them off a single thermostat or two? @Joe917, do you have any thoughts on this? If I go this route, I'd likely go with an external mounted option. The only places I can think of where I can route an inlet/outlet is in the current "dog room" or in the shoe cabinet and use the space where the extinguishers are.
Joe917
Explorer
I would go to a bigger unit before two units. My understanding is most of the issues with coolant heaters comes from being oversized and not working enough. We had no issues with comfort at -20C for weeks at a time, We did live in it Feb to Aug here. You must maintain the heat, it is very slow to heat from cold . The biggest PITA for us in winter was the single layer glass windows and condensation.
where_the_heffalump_roams
Active member
Right. I keep the “blinds” up at night to help with that extra little bit of insulation. I also insulate the ceiling vents. I’m also loosing some heat at the stairwell so I’ll make a floorboard to go over that in the winter. Still using the quilt that guys made for the doorway 
.
I keep the thermostat between 20c-22c. It’s been between -2c to -10c at night this past week and the webasto runs constant to keep internal temps above 20c after the sun goes down. It’s heating the radiators. But I’m assuming that it can’t heat up the coolant any warmer. It’s been that way the past 2 winters. I even thought about rerouting the radiator in the external hatch to the inside to help a bit more.
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. I keep the thermostat between 20c-22c. It’s been between -2c to -10c at night this past week and the webasto runs constant to keep internal temps above 20c after the sun goes down. It’s heating the radiators. But I’m assuming that it can’t heat up the coolant any warmer. It’s been that way the past 2 winters. I even thought about rerouting the radiator in the external hatch to the inside to help a bit more.
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Neil
Observer
It sounds like the cabin is losing heat at an alarming rate if you need to run the heating all night to maintain a livable tempreture.
At minus 25 we only had to run our heating for about 45 mins. Then provided you didn't open the windows or doors it remained warm until the morning.
Condensation is a killer in many ways , you windows could be the source of your heat loss.
I think I remember in a previous post several years ago that Jo had combined the engine loop with the domestic loop.
If this is tge case are you also heating the engine block all night as well.
If so I would seperate these loops with a heat exchanger
Sound like your in a frustrating situation.
Feel for you
Neil
At minus 25 we only had to run our heating for about 45 mins. Then provided you didn't open the windows or doors it remained warm until the morning.
Condensation is a killer in many ways , you windows could be the source of your heat loss.
I think I remember in a previous post several years ago that Jo had combined the engine loop with the domestic loop.
If this is tge case are you also heating the engine block all night as well.
If so I would seperate these loops with a heat exchanger
Sound like your in a frustrating situation.
Feel for you
Neil
Joe917
Explorer
The Webasto should not be running continuously. At -2C to -10C I would expect well less than half the time. The truck is quiet enough at night that you hear the Webasto fire up, I would know it was cold when I heard it.
The loops do not need to be separated with a heat exchanger. I have not changed the system layout original to the truck and designed by a Webasto installer.
The valve that separates the loops does have to be closed manually. It is the valve in the driver's side wheel arch. If that is not closed you would be heating the engine block too. It has to be open to heat the cabin or domestic hwt from engine heat or to preheat the engine. It needs to be closed when heating the cabin with the Webasto. Are you forgetting to close the valve?
The loops do not need to be separated with a heat exchanger. I have not changed the system layout original to the truck and designed by a Webasto installer.
The valve that separates the loops does have to be closed manually. It is the valve in the driver's side wheel arch. If that is not closed you would be heating the engine block too. It has to be open to heat the cabin or domestic hwt from engine heat or to preheat the engine. It needs to be closed when heating the cabin with the Webasto. Are you forgetting to close the valve?
joeblack5
Active member
I did not read back what heater you have, but if it is webasto tsl17 then it has two settings, high and low. The file line should be very small, like 2mm id so that bubbles cannot stay behind and accumulate.
It also would be good if you get some more numbers, like what is the actual coolant temp before and after the heater. Maybe it runs all the time on medium setting because you have reached the max coolant temp for the webasto.
In that case you need larger radiators or bigger fan to lower the coolant temp and make it kick into high mode.
In our e350 bus conversion the engine is plumbed in parallel to the heaters. With one valve I stop the flow thru the engine but by keeping the other valve open I still use the expansion tank from the engine,....saves some space...
22c is pretty darn luxury... I have a sweater on way before that.
In general I think it is more the draft that blows away most of the heat.
In Dory,our 34 ft low floor bus we use a webasto tsl17, floor heat and additional radiator with a squirrel cage fan.
The webasto is to small for that volume ,insulation and draft.. I am planning to run a stainless chimney pipe vertically thru the bus to gain some heat from the webasto exhaust , these mini boilers are not all that efficient and lots of heat gets wasted that way.
Good luck Johan.
It also would be good if you get some more numbers, like what is the actual coolant temp before and after the heater. Maybe it runs all the time on medium setting because you have reached the max coolant temp for the webasto.
In that case you need larger radiators or bigger fan to lower the coolant temp and make it kick into high mode.
In our e350 bus conversion the engine is plumbed in parallel to the heaters. With one valve I stop the flow thru the engine but by keeping the other valve open I still use the expansion tank from the engine,....saves some space...
22c is pretty darn luxury... I have a sweater on way before that.
In general I think it is more the draft that blows away most of the heat.
In Dory,our 34 ft low floor bus we use a webasto tsl17, floor heat and additional radiator with a squirrel cage fan.
The webasto is to small for that volume ,insulation and draft.. I am planning to run a stainless chimney pipe vertically thru the bus to gain some heat from the webasto exhaust , these mini boilers are not all that efficient and lots of heat gets wasted that way.
Good luck Johan.
where_the_heffalump_roams
Active member
The valve is kept open when driving. I let it heat up the habitat enough so that is it’s actually a bit uncomfortably warm at times over 28c so that I can carry the “free” heat into the evening/night. The valve between the engine and webasto is closed when parked and opened up about 1 hr prior to driving.
Depending on how cold it is outside, I take the temps down a bit. But I don’t think I’ve ever set the thermostat lower than 18c as it takes too long to heat back up. Regardless of the temp settings, the webasto has def been working to maintain the set temp. I’ve not changed any settings and actually didn’t know there was a mid/high function. The current unit is a rebuilt webasto thermo top c.
It’s currently -6c here in Nevada and I’m at 1500 meters. The webasto has been running for at least a few hours to maintain temps at 21c. It’s def working and keeping it cozy. My concern is if I’m running it past its max efficiency and possibly why the last heater didn’t last me 2 full winter seasons. Maybe that was a fluke though? If they are made to run constant like this I’d run with it. Just trying to check all the boxes on this as I want to be able to confidently venture out further where there will be less resources.
This week I’m hoping to have the brakes serviced with new liners and get the drums machined. I couldn’t find a place in California that could help.
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Depending on how cold it is outside, I take the temps down a bit. But I don’t think I’ve ever set the thermostat lower than 18c as it takes too long to heat back up. Regardless of the temp settings, the webasto has def been working to maintain the set temp. I’ve not changed any settings and actually didn’t know there was a mid/high function. The current unit is a rebuilt webasto thermo top c.
It’s currently -6c here in Nevada and I’m at 1500 meters. The webasto has been running for at least a few hours to maintain temps at 21c. It’s def working and keeping it cozy. My concern is if I’m running it past its max efficiency and possibly why the last heater didn’t last me 2 full winter seasons. Maybe that was a fluke though? If they are made to run constant like this I’d run with it. Just trying to check all the boxes on this as I want to be able to confidently venture out further where there will be less resources.
This week I’m hoping to have the brakes serviced with new liners and get the drums machined. I couldn’t find a place in California that could help.
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Neil
Observer
You are correct, they do not need to be separated by a heat exchanger. However, this is probably the only truck with a hydronic system that I have heard of that isn't.
It's pretty standard to stop all the bits of metal and crud that circulates around a cast iron engine block being pushed through the heating system and the heater.
It also means that the two loops can work at different pressures. Lastly it means you can have radiators in the living area higher than the engine expansion tank. By looping them together, your highest radiator in the system becomes the expansion tank, that isn't good.
But you are correct, they don't need to be, but it is good practice
Neil
where_the_heffalump_roams
Active member
Here is the current configuration. I swapped out the fuel line that connects the filter to the fuel pump for one that has a 4mm or 5/16ths ID a few days ago. On the pump side, I slide in a "reducer" that came with a webasto rebuild kit. This is the smallest ID line I can use with that reducer. I'm sure I can shorten up the line a bit, but I'm not sure if that would help at all.
I'll fire fire up the Webasto later today, but as you can see, the filter is dry again. The Webasto was last on about 3 hours ago. Hasn't been needed since that time as I was driving. If I want to use a check valve, I'll gave to order one. No auto store around me has any in stock. But I'm also interested in why this is an issue now where it wasn't before. I'm open to feedback.
Thanks!
I'll fire fire up the Webasto later today, but as you can see, the filter is dry again. The Webasto was last on about 3 hours ago. Hasn't been needed since that time as I was driving. If I want to use a check valve, I'll gave to order one. No auto store around me has any in stock. But I'm also interested in why this is an issue now where it wasn't before. I'm open to feedback.
Thanks!
Last edited:
joeblack5
Active member
The pump has build in check valves.. my pumps are mounted real close to the file tank and as low as possible. So the pump pushes fuel thru the line.
I would take smaller fuel line, 4 mm is a lot of volume , also rubber line absorb fuel pulses , might be less noisy but maybe unintended consequences.
Maybe disconnect the feed side of the pump and observe of fuel drops back out of it?? Assuming pump is lower then webasto.
Good luck
Johan
I would take smaller fuel line, 4 mm is a lot of volume , also rubber line absorb fuel pulses , might be less noisy but maybe unintended consequences.
Maybe disconnect the feed side of the pump and observe of fuel drops back out of it?? Assuming pump is lower then webasto.
Good luck
Johan
Fundamentally, the only way for air to fill that line is if air gets drawn in somewhere, typically meaning fuel goes out too. Your pump would usually be a set of check valves, and shouldn’t allow flow backwards. Either the pump is failed open or partially open, or you have a leak.
2 other notes:
1- IF your pump is failing, it is possibly not moving enough fuel, thus simulating low fire all the time and contributing to your heat problem? It’s a possibility, although without seeing the system in person it would be hard to say for sure.
2- Technicality, but 5/16” = 8 mm, not 4, that is a huge difference in volume, so it could be useful to those helping you troubleshoot to know which you have. Guessing from looking at your pictures… 8mm line?
2 other notes:
1- IF your pump is failing, it is possibly not moving enough fuel, thus simulating low fire all the time and contributing to your heat problem? It’s a possibility, although without seeing the system in person it would be hard to say for sure.
2- Technicality, but 5/16” = 8 mm, not 4, that is a huge difference in volume, so it could be useful to those helping you troubleshoot to know which you have. Guessing from looking at your pictures… 8mm line?