Moody 44 weird heating setup …or is it

[Devon Boy]

Dear All,

I’m currently working on a Moody 44 which has 3 blown air ventilation using that appear to heat through hot water pipes circulating around the boat.


However, there appears to be two valves that potentially control the flow of water in some way, I’m assuming to the heating units. So from the calorifier you can send hot water around the circuit and to the air units or turn them off and have cold air.

But for some reason this seems to not work in any orientation even if the water is hot. There is also a push button labeled “circulating pump” which also makes not a jot of difference! Any ideas??

Picture attached for clarity. iCloud Photos - Apple iCloud

 

[AngusMcDoon]

A hydronic system with a dual coil calorifier sometimes has what's known as a summer valve. This allows you to run the heating to heat the water in the calorifier but not send it round the cabin heating circuit to the matrices. Even without each matrix fan on sending hot water round their circuit would unnecessarily heat the cabin a bit.

 

[[2574]]

Our Malö 43 has a very similar system, it’s very effective. The “circulating pump” switch is there to start the heater pump to circulate hot engine coolant water through the calorifier and fan matrices. Thus, when motoring, hot water and cabin heat can be generated without firing the Eberspacher. The same pump is energised automatically when the Eberspacher is on hence it makes not a jot of difference when using the heater but makes all the difference when motoring.

 

[Minerva]

Our Malö 43 has a very similar system, it’s very effective. The “circulating pump” switch is there to start the heater pump to circulate hot engine coolant water through the calorifier and fan matrices. Thus, when motoring, hot water and cabin heat can be generated without firing the Eberspacher. The same pump is energised automatically when the Eberspacher is on hence it makes not a jot of difference when using the heater but makes all the difference when motoring.

That seems like a jolly good idea to have on a boat used year round! Need to store that idea in my mind for a future upgrade

 

[Devon Boy]

It’s a great idea but it won’t bloody work .

There is also two small black water pumps and one runs the other doesn’t. I’m wondering if this is the issue.

 

[NormanS]

That seems like a jolly good idea to have on a boat used year round! Need to store that idea in my mind for a future upgrade

I tapped into the hot water supply going to the calorifier, and fed it through a heater matrix (from a Ford Transit). The box containing the matrix has 75mm ducting, and air is driven through it with an in-line fan. Ah the joy of motoring, when inside the deck saloon in the cold.

 

[Tranona]

It’s a great idea but it won’t bloody work .

There is also two small black water pumps and one runs the other doesn’t. I’m wondering if this is the issue.

Post#3 explains how it works. There should also be an Eberspacher diesel fired heater which is the primary source of heating the water. As explained the valves and pump enable you to also use hot water from the engine circuit when motoring.

Don't this has anything to do with black water pumps which are for emptying holding tanks.

 

[Devon Boy]

Ah there is a known issue with the eberspacher water heater which is due to be serviced / replaced but I had assumed that it should still work without. I feel some more investigation may be in order.