Raw Water Cooled BMC 1800 and Calorifier

[TheSaintlyOne]

Has anyone added a Calorifier to a Raw Water Cooled BMC 1800. I know it can be done successfully but details are sketchy. The tax man has been kind with a rebate and Im looking to add a surecal 55L calorifier to our narrowboat most likely a vertical one in the cupboard by the door. 

 

In terms of our bleeding scenario below we have recently returned to the boat to discover a pair of coots nesting in a fender so further movement or starting is currently limited but we are adding an automatic fuel lift pump and other suggestions recieved here to see how that helps. 

 

But in the meantime plan to tackle the issue of currently having no runming hot water 

 

Regards 

[David Mack]

I would plumb the calorifier in series with the engine, so hot water from the engine passes through the calorifier coil before being discharged overboard (or into a wet exhaust). 

But does a direct cooled engine run hot enough to heat a calorifier?

[TheSaintlyOne]

12 minutes ago, David Mack said:

I would plumb the calorifier in series with the engine, so hot water from the engine passes through the calorifier coil before being discharged overboard (or into a wet exhaust). 

But does a direct cooled engine run hot enough to heat a calorifier?

 

The old question and the simple awnser is yes as long as its plumbed into the correct part of the engine. That much I do know. Plenty of raw water engines run calorifiers but info on doing it on a BMC is limited though i am aware of the position of one of the inlets/outlets 

[Tony Brooks]

Hole hard - if it really is direct raw water cooled, then its far more complicated than the replies above suggest. I will need a photo of the front of the engine.

 

If it is indirect raw water cooled (heat exchanger cooled) then it is as simple. There is normally a tapping at the front, back or both on the starboard side of the head under a hexagon blanking plug. That is the take off to the calorifier. The return goes into the host that runs into the water pump.

 

[TheSaintlyOne]

6 minutes ago, Tony Brooks said:

Hole hard - if it really is direct raw water cooled, then its far more complicated than the replies above suggest. I will need a photo of the front of the engine.

 

If it is indirect raw water cooled (heat exchanger cooled) then it is as simple. There is normally a tapping at the front, back or both on the starboard side of the head under a hexagon blanking plug. That is the take off to the calorifier. The return goes into the host that runs into the water pump.

 

 

This was our engine when purchased before it went in the boat so I think correct me if im wrong it has a heat exchanger 

[Tony Brooks]

Yes, heat exchanger. I think I was wrong about the take-off port. Its on the port side and is probably that hexagon head to the left of the long filter mounting head stud in the first photo. There may be one in a similar position on the front.

[TheSaintlyOne]

4 minutes ago, Tony Brooks said:

Yes, heat exchanger. I think I was wrong about the take-off port. Its on the port side and is probably that hexagon head to the left of the long filter mounting head stud in the first photo. There may be one in a similar position on the front.

Great so relatively straight forward then saw that nut on another picture on another forum post  I have heard that that tapping point is an odd size???

[Tracy D'arth]

25 minutes ago, TheSaintlyOne said:

Great so relatively straight forward then saw that nut on another picture on another forum post  I have heard that that tapping point is an odd size???

Use the rear tapping on the head for the flow to the bottom of the calorifier coil, top coil to the return at the water pump, you need to add a tee to make this connection. It will bleed better this way and is more efficient.

  Head tapping on a 1.8D is NPT thread, on a 1.5D its 1/2" BSP.  Calcutt can provide the NPT one.  Some heads are reworked ones from the factory so check first, BMC were fond of making unannounced changes!  NPT is the same thread as electrical conduit if that helps.

Edited June 29, 2021 by Tracy D'arth

[TheSaintlyOne]

8 minutes ago, Tracy D'arth said:

Use the rear tapping on the head for the flow to the bottom of the calorifier coil, top coil to the return at the water pump, you need to add a tee to make this connection. It will bleed better this way and is more efficient.

  Head tapping on a 1.8D is NPT thread, on a 1.5D its 1/2" BSP.  Calcutt can provide the NPT one.  Some heads are reworked ones from the factory so check first, BMC were fond of making unannounced changes!  NPT is the same thread as electrical conduit if that helps.

 

Great Thanks glad to hear its not too much of an issue. 

 

Regards