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Webasto coolant temperature problem


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11 hours ago, Mike Adams said:

It can only be not enough fuel or the heat energy  is being dissipated too quickly if the heater body is not getting hot. If you disconnect the dosing pump from the heater and connect the output of the pump into a jar you can check how much fuel is coming through. If you get a good squirt each time the pump ticks it is probably OK. They are fixed delivery, each time it pulses you get so many cc. Check that after the heater gets up to temperature the pulse rate doesn't slow down. I have found it helpful in the past to wire an LED indicator  in parallel with the pump so you can see when it ticks. I also wired an LED indicator in parallel with the heater. By just looking at the LED's I could see if everything was going normally as my heater was in the engine compartment. Remember that with lower ambient  temperatures the rads will dissipate much more heat than in the summer. On my current setup if the boat is cold or near freezing the heater will run flat out for several hours before it shuts down whereas when it is warmer it is only about an hour.

Thanks, I know the pump definately doesn't slow down, infact it ticks quickly at over twice per second pretty much throughout...great idea with the LED's. It's a fair point about the rads dissipating heat but the problem is at the output of the heater itself where the water is not hot on the outlet 

11 hours ago, Sea Dog said:

Change it - it's a periodic anyway on rubber hoses, so your work won't be wasted, and one of the age failure mechanisms is swelling, which could be the cause of any fuel starvation.

Yes, will have a look

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If you disconnect the circulating pump and switch the heater on within a couple of minutes the heater body should be too hot to touch and it will then shut down. If it doesn't shut down that quickly you may not be getting enough fuel.

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1 hour ago, Tracy D'arth said:

Is there a section of pipe that you cannot see which is in standing water in the bilge trying to heat the canal?

Hi, no there isn’t, everything is surface mounted I can see the whole run

3 hours ago, Cas446 said:

If you have fuel starvation the unit will slow the circulation pump down and the entire system never gets up to temperature, but still runs. Check your fuel lines as others have said.

Currently got 6mm fuel hose and have been advised to reduce it to 3.5mm internal bore. I will do this

as the 6mm probs my to big to suck fuel through...but it did work splendidly for a couple of months...

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4 hours ago, Lumisid said:

Thanks, I know the pump definately doesn't slow down, infact it ticks quickly at over twice per second pretty much throughout...great idea with the LED's. It's a fair point about the rads dissipating heat but the problem is at the output of the heater itself where the water is not hot on the outlet 

Yes, will have a look

I have never measured it, but I would estimate that the temp difference between water going into the Webasto and water coming out is about 20c.  This will be less with a ‘faster water circulator’.  So cold water in will still be cool water out. Until all the rads and coolant etc have warmed up.

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52 minutes ago, Chewbacka said:

I have never measured it, but I would estimate that the temp difference between water going into the Webasto and water coming out is about 20c.  This will be less with a ‘faster water circulator’.  So cold water in will still be cool water out. Until all the rads and coolant etc have warmed up.

That is why I asked how long the OP had let it run and he said 2a full cycle, about 70 minutes or so". That shoudl be long enough to get the rads more then just warm.

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1 hour ago, Tony Brooks said:

That is why I asked how long the OP had let it run and he said 2a full cycle, about 70 minutes or so". That shoudl be long enough to get the rads more then just warm.

With a cold calorifier and 5 rads in a boat that has been empty for days, so everything is cold, after an hours continuous running my rads are warm but not hot to touch.

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39 minutes ago, Chewbacka said:

With a cold calorifier and 5 rads in a boat that has been empty for days, so everything is cold, after an hours continuous running my rads are warm but not hot to touch.

Not my experience with a 4kw Eberspacher and 3 rads. Even when returning to a stone cold boat in winter, after an hour of the Eber the 57' boat is  warm and there's plenty of hot water. The rads are redders well within 30 mins. I only ever use mine in the one hour burst mode. After the hour, the solid fuel stove has the weight anyway.

Edited by Sea Dog
Radiator time to hot
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Hi all, thanks for your comments and just an update 

i changed my fuel lines and made sure there was good dosage from fuel pump on start up. All seems to be good.

on turning the rads off the calorifier heats up quickly and it's the same vice versa if I turn calorifier valves down rads heat up quickly 

im guessing now it's a question of balancing the flow between the calorifier and the rads to get that sweet spot...!

i have two valves on the calorifier one on flow and one on return, it seemed to work well with the flow (in) wide open and the return nearly shut. Sorry if I'm mixing terminology,

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53 minutes ago, Lumisid said:

Hi all, thanks for your comments and just an update 

i changed my fuel lines and made sure there was good dosage from fuel pump on start up. All seems to be good.

on turning the rads off the calorifier heats up quickly and it's the same vice versa if I turn calorifier valves down rads heat up quickly 

im guessing now it's a question of balancing the flow between the calorifier and the rads to get that sweet spot...!

i have two valves on the calorifier one on flow and one on return, it seemed to work well with the flow (in) wide open and the return nearly shut. Sorry if I'm mixing terminology,

Are all you rads also balanced?

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Hi all, I’m finding that if I close off rads (I have 2 lever valves on the main spine) the calorifier gets hot v quickly. However when removing the calorifier from the circuit and opening the rads they do not heat at the same level. I know above I had written that they did heat up once I had turned calorifier off (after it being heated) but if starting from cold they do not get up to temp. Seem to be going round and round with this. Any ideas welcome...

 

one extra point to add -when system worked well the air intake, on startup, was always noisier than it is now. It would make a slight howling for 10-20 secs, then back off and then boiler would really cook. It doesn’t do that any more. Not sure if this is related...Anyone have experience with this? 
 

Thanks

 

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Why not get it checked out on a test bed? You can pee about for hours/days and still get no where. When mine last went tits up I sent it to my usual bod who diagnosed, cleaned and put new water pump in and returned for a total cost of 100 squids within 3 days. Job done. That was 3 winters ago and still starts and runs first time every time and we use it quite often as back up as full time liveaboards.

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3 minutes ago, mrsmelly said:

Why not get it checked out on a test bed? You can pee about for hours/days and still get no where. When mine last went tits up I sent it to my usual bod who diagnosed, cleaned and put new water pump in and returned for a total cost of 100 squids within 3 days. Job done. That was 3 winters ago and still starts and runs first time every time and we use it quite often as back up as full time liveaboards.

I totally agree, I'm right on the cusp of doing just that...!

  • Greenie 1
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