More hot water?

[DaveR]

Good morning.

 

On Legacy we have a twin coil calorifier, 55 ltr manufactured in about 2007. The second coil is not used & is blanked off as the central heating unit has been removed.

 

I have fitted temperature sensors to the skin of the calorifier and, after a few hours cruising, get the results : top 60C mid level 40C and lowest level 30C.

 

Not knowing the internal layout of the tank, I don't know if the two coils are at the same level. I believe in vertical calorifiers they are but have no knowledge of horizontal ones.

 

I would like to generate more hot water and ask if it would be practical to connect the second coil (22mm) in line with the first coil (15mm) - with the usual adaptors.

 

Questions : could the coils in a horizontal calorifier be at different vertical levels? I have been unable to find any diagrams of possible internal layout. Made more difficult by not knowing the manufacturer.

Will the engine jacket water pump be powerful enough to push the water around a second coil? Calorifier is located under the bed with 3m of pipework to the engine.

 

Thank you

 

Dave R

 

[Chewbacka]

I think on a horizontal calorifier the coil is cranked down to put it towards the bottom of the tank.  Is it possible the tank when installed had been rotated so the heating coil is towards the top of the tank?  That would give you the effect you are seeing.  An easy way to check is to confirm the hot take off pipe is at the top of the tank and not low down.

[Tony Brooks]

I suspect the hot take off will not be marked. If you twist the calorifier through 180 degrees the cold inlet becomes the hot outlet and the hot outlet becomes the cold inlet. If any PRV and non-return valve were definitely fitted by the manufacturers than that would tell you.

 

The horizontal calorifiers I dealt with (1970s/80s) had a sort of double  walled tube running down the centre of the calorifier with the engine water between the two walls. The engine inlet and outlet were dead centre and the   tube hang below the inlet and outlet by one tube diameter.

[DaveR]

Thank you for the thoughts. The connections on the tank are all on the top-side of the tank - somewhat different from the SureCal ones. Should have included this information in the original post.

 

The line up is 

 

Hot water out

22mm CH input

22mm CH outlet

Immersion heater boss ( 1kw unit fitted)

15mm input from engine

15mm outlet from engine

Pressure relief valve

Cold water in.

 

Regards

 

Dave R

 

[David Mack]

How do you drain a calorifier with all the connections on the top?

[Onewheeler]

You could put a small recirc pump on the domestic side, arranged to be on when the engine is running (or under manual control maybe better so you can get HW from a short engine run).

[Chewbacka]

If the connections are on the side is the hot outlet close to one end and the cold inlet close to the other end?  If so it might be a vertical calorifier mounted on it's side which would also explain why it only gets hot to about half way as the heating coil will lie on the centre axis. 

[Guest]

A few mysteries to be considered as noted above.

Putting the two coils in series is going to heat the water quicker. I have exactly this arrangement and did before and after checks. The engine pump should have no problem as the head will be the same and the circuit resistance only slightly higher.

Whether you get 'more' water depends upon the points noted above although natural circulation may get you what you want.

Another thought. The 60 degrees may indicate that the cylinder simply hasn't reached full temperature. What temperature does the engine water circulate at? I know mine is at least 70 as that is what my cylinder gets to at the top.

[DaveR]

7 hours ago, David Mack said:

How do you drain a calorifier with all the connections on the top?

I use a hand operated stirup air pump and push the water out through the cold connection.

4 hours ago, Chewbacka said:

If the connections are on the side is the hot outlet close to one end and the cold inlet close to the other end?  If so it might be a vertical calorifier mounted on it's side which would also explain why it only gets hot to about half way as the heating coil will lie on the centre axis. 

The cylinder has domed ends at both ends so can not stand up