sthurley
Active Member
Hello, can anyone advise which is the outward flow for the calorifier connection on the md2020d-bt?
Volvo md2020d-bt
- Thread starter sthurley
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VicS
Well-Known Member
sthurley
Active Member
Hi, thanks. Do you reckon the top is the outlet and the side is return?
RichardS
N/A
The usual arrangement is that both the hot engine water and the cold fresh water feed go into the calorifier at the lower connections.
Richard
Richard
VicS
Well-Known Member
I was thinking the other way round. The hot water flow being from the engine via the square port you can see in this diagram the return to the pump via the top connection, but I don't know for sure
https://www.marinepartseurope.com/en/volvo-penta-explodedview-7740690-26-2434.aspx
paul-essex
Well-Known Member
I would thik hot water comes out the side and back to the top as I would expect the thermostat to be on the flow as pic
Plevier
Well-Known Member
I am 99% sure from memory that the flow is the top - vertical - one, return at side. The side port does not go into the pump but into a gallery.
My 2020D (factory installed with Cleghorn Waring calorifier in a Jeanneau) did not have the in line thermostat shown in one of the above drawings. I can't see any point in it.
I doubt if it really matters which you connect to which calorifier port. Although conventionally you plumb flow to the bottom of a hot cylinder, in this case there is so much pump effect I don't think it will make any difference.
In fact I have seen a recommendation to take the hot to the top of the calorifier - but I can't remember the reason that was given! It may have been for easier bleeding.
My 2020D (factory installed with Cleghorn Waring calorifier in a Jeanneau) did not have the in line thermostat shown in one of the above drawings. I can't see any point in it.
I doubt if it really matters which you connect to which calorifier port. Although conventionally you plumb flow to the bottom of a hot cylinder, in this case there is so much pump effect I don't think it will make any difference.
In fact I have seen a recommendation to take the hot to the top of the calorifier - but I can't remember the reason that was given! It may have been for easier bleeding.
paul-essex
Well-Known Member
the reason for a stat is to stop the flow of water untill it is hot otherwise it will cool the calorifier before it heats it up
shaunksb
Well-Known Member
and to ensure the engine itself reaches optimum temperature as quickly as possible.
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sthurley
Active Member
Makes sense, however the inline thermostat is marked as out of production. Whilst others may be bought, is it really a necessary expense? As the engine gets up to temp, you are explaining that the calorifier will be cooled, surely it would not really matter as the engine should reach temp pretty quickly and the calorifier will be heated again?
Plevier
Well-Known Member
Do you think that would be a significant effect? Any hot water already in the unit will be at the top, above the heating coil. The engine heats up very quickly anyway.
Plevier
Well-Known Member
Having thought about this - that funny thermostat appears to be in line, remote from the engine and the calorifier, so if it is closed when cold and there is no flow, how will it know when to open?
I wonder if it actually closes when very hot to limit calorifier water temperature?
Still seems unnecessary to me!
