How hot does your diesel heater blow?

I had a DW80 on my 48' yacht with 5 "radiators" that blew hot air out into the cabin. It also never seemed to get hot enough. The key thing is to measure the output water temperature. I believe they changed the thermostat and reduced the output temp to 75C from 85C.

I think part of the problem I had was that my system leaked and then the boiler would cut out. You can download the workshop manual which I found very useful. I think the Thermo 90 is pretty much identical and can be used as a guide if you cannot find the DW80.

I admin in the end I replaced the DW80 with a Thermo 90 as I kept spending money on the old one and not getting it to work properly but mine was in shocking condition... Good luck!

ps the new one is excellent!!!
 
DickB said:
I had a DW80 on my 48' yacht with 5 "radiators" that blew hot air out into the cabin. It also never seemed to get hot enough. The key thing is to measure the output water temperature. I believe they changed the thermostat and reduced the output temp to 75C from 85C.

I think part of the problem I had was that my system leaked and then the boiler would cut out. You can download the workshop manual which I found very useful. I think the Thermo 90 is pretty much identical and can be used as a guide if you cannot find the DW80.

I admin in the end I replaced the DW80 with a Thermo 90 as I kept spending money on the old one and not getting it to work properly but mine was in shocking condition... Good luck!

ps the new one is excellent!!!
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Interesting. So if the old dw80 was almost the same as the thermo 90 did you figure what made the difference? I assume you left all up the internal piping and matrix blowers the same and just swapped over the actual unit?

Also I take it you don't have the old DW80 kicking about do you?
 
northcave said:
Interesting. So if the old dw80 was almost the same as the thermo 90 did you figure what made the difference?
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The loss of efficiency due to lack of correct burn rate adjustment will have some effect as will any calcification inside the heat exchanger, it's why I use descaler in my test tank during post service test and set up, surprising the amount of scal that drops into the return strainer on the test tank, especially if the inhibitor regime has been ignored. One other thing that can reduce efficiency is too high an antifreeze concentration, 25% is as much as you need.
 
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northcave said:
Hmm I just went on the instructions which was 50% that's frustrating as it was a right faff getting it in via a watering can.
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That's old advice and not for marine, it is a hangover from when they were installed on engines wher they had to have the engine manufacturers ratio, stand alone heaters use 25%, in fact I often use as low as 15% where the AF manufacturer states that will protect down to -8 but I am in the south.
 
David2452 said:
That's old advice and not for marine, it is a hangover from when they were installed on engines wher they had to have the engine manufacturers ratio, stand alone heaters use 25%, in fact I often use as low as 15% where the AF manufacturer states that will protect down to -8 but I am in the south.
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Thanks. How much difference does it really make and also if I just fill the header tank with normal water and drain some out via the matrix units I assume over time it will all mix up again evenly or would you drain the whole system and start again?

I got my pipe lagging already so might try and get that installed tonight and see what happens.
 
northcave said:
Thanks. How much difference does it really make and also if I just fill the header tank with normal water and drain some out via the matrix units I assume over time it will all mix up again evenly or would you drain the whole system and start again?

I got my pipe lagging already so might try and get that installed tonight and see what happens.
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I would make sure it's properly mixed unless you have an in out header, in which case you could just trickle water in with the pump on and it will mix, if it's one of the horrid single pipe ones then you will need to take it out, mix it and put it back. It makes a material difference, I have drained down new installs by customers (and builders) who didn't read the instructions and put 50% in which were below par, just remixed and refilled and all was well.
 
David2452 said:
I would make sure it's properly mixed unless you have an in out header, in which case you could just trickle water in with the pump on and it will mix, if it's one of the horrid single pipe ones then you will need to take it out, mix it and put it back. It makes a material difference, I have drained down new installs by customers (and builders) who didn't read the instructions and put 50% in which were below par, just remixed and refilled and all was well.
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Ok thanks. It is a in and out header so I'll try that after I've added the lagging.
 
nicho said:
To answer the original question, our 4 outlet Eberspacher heating gets very hot, especially the aft cabin and the heads which are closest to the heater.,I have to close the vents by around 3/4 to keep the temperature down.
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Just for clarity the OPs header is a bit misleading as he doesn't have an air heater but a matrix based system, a horse of an entirely different colour which operates at lower temperatures.
 
Ok so I was adding my Armaflex to the pipes last night and trying to deduce the pipe arrangement. It appears as though it ducts all the way amidships first to a 3 way value which can be selected to "Water and Heat" or "Water Only". So it appears as though I have no choice but to heat the hot water calorifier with the diesel heater.

Does that tend to be normal? I appreciate how it can be an advantage but I'd have though the default position would be Heat Only of which my current setup does not have that option.

It then appears to separate off to the bow and stern matrix units (4 in total). There is A LOT of piping which is basically heating every locker and underfloor space available other than the cabins until I have fit all this insulation.
 
northcave said:
Ok so I was adding my Armaflex to the pipes last night and trying to deduce the pipe arrangement. It appears as though it ducts all the way amidships first to a 3 way value which can be selected to "Water and Heat" or "Water Only". So it appears as though I have no choice but to heat the hot water calorifier with the diesel heater.

Does that tend to be normal? I appreciate how it can be an advantage but I'd have though the default position would be Heat Only of which my current setup does not have that option.

It then appears to separate off to the bow and stern matrix units (4 in total). There is A LOT of piping which is basically heating every locker and underfloor space available other than the cabins until I have fit all this insulation.
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Not normal at all, the usual arrangement is balance valves which allow not only the usual balancing but either hot water only, heating only or both, though hot water only is always a bad idea with an evaporator heater.
 
David2452 said:
Not normal at all, the usual arrangement is balance valves which allow not only the usual balancing but either hot water only, heating only or both, though hot water only is always a bad idea with an evaporator heater.
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I'll have a look at the piping and see if it can be modified to heat only. I see no need to have the calorifier heated to temp before the Webasto dedicates itself to cabin heat... especially when the engine and/or genset can heat water quickly if necessary.
 
northcave said:
I'll have a look at the piping and see if it can be modified to heat only. I see no need to have the calorifier heated to temp before the Webasto dedicates itself to cabin heat... especially when the engine and/or genset can heat water quickly if necessary.
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Just bung a valve in the feed or return branch to the calorifier coil.
 
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