Calorifier Not Getting Hot

[smitch6]

Hi i have a 1.5 BMC and an upright calorifier make unknown,

closed engine system goes into the side and the fresh water go in the top.

i was running the engine for a few hours the other day on land with a hosepipe in the raw water filter to cool the engine,

the engine got nice and warm and 1 pipe going into the calorifer got warm too, but the 1 coming out didn't ......

the thermostat is a 79º  one and that opened at 1 point and the temperature then went down quite a bit, but still the pipe didn't get warm.

the water level in the bowman went down a bit when the thermostat opened but didn't move much after that.

i would suggest i have an air leak but how on earth can i get rid of it?

i tried to remove a pipe and water came out.

i have put a brand new water pump on there as that was leaking

[Vaughan]

Assuming you have not changed the pipework around, it will just need air bleeding out.

Run the engine until the thermostat opens, making sure that the system is well topped up with coolant. With the engine running and the header tank pressure cap still on, unscrew the Jubilee clip on the hose coming from the top of the calorifier, at the engine end, loosen the hose and let water and air out, under the pressure in the system. You will feel the hose start to get hot in your hand as the coolant starts to flow. 

If that doesn't work, we will try to trace the fault further!

And keep your hands away from the alternator pulley, when you have the engine running!

[Regulo]

One of two possibilities: 1) an air lock, 2) A blockage.

If you've removed the top pipe into the calorifier and water came out, It's unlikely to be 1)

Which leaves 2). Remove both pipes into the calorifier, and reverse flush it.

Without seeing the runs of the pipework, and situations of the respective engine and calorifier, it's difficult to be more specific. Got anyone local to assist in your efforts?

Edit: Cross posted with Vaughan!

[annv]

Hi You say that the cold supply connects to top of caloforier this not usall, cold supply from fresh water tank pump goes into the lower pipe, hot water pipe to taps comes out of top pipe on the calorifier, the two pipes from engine flow and return go in the side/lower coils the top one goes/from engine cylinder head outlet and the bottom/lower one goes back to engine water circulating pump,  with engine running doesn't matter if hot or cold with cap on heat exchanger removed and coolant  (50/50 antifreeze) level/full to top remove/loosen higher /top hose from engine to calorifier coils at the caloforier until only water comes out and push back on and retighten you need at same time to refill/maintain water/coolant level in heat exchanger 1 1/2 inches from bottom of cap, replace cap run until engine hot both pipe should be hot to touch after 1/4 to 1/2 hour you should get hot water from taps. John 

[Smoggy]

5 hours ago, annv said:

Hi You say that the cold supply connects to top of caloforier this not usall,

That is how mine was plumbed when I got the boat, strangely enough very little hot water, swapped them round and loads of hot water.

As Annv says engine coolant pipes normally go in and out of the side, cold domestic water in to the bottom, hot domestic water out the top, a non-return valve on the inlet piping stops hot water going back into the cold system as it expands, there should be an expansion tank somewhere on the system either between non-retun and calorifier on the inlet or on the outlet.(first option is best or you get the cooling expansion tank full first)

[Vaughan]

You are also more likely to get an airlock if the calorifier is sited at a higher level than the engine. This may sound impractical but in some boats it has to be that way. This is why purging the system when it is under pressure with the engine running, becomes necessary.

[smitch6]

2 hours ago, Vaughan said:

You are also more likely to get an airlock if the calorifier is sited at a higher level than the engine. This may sound impractical but in some boats it has to be that way. This is why purging the system when it is under pressure with the engine running, becomes necessary.

it is higher than the engine slightly by about 6" i'd say.

how do you purge it? i'm down there today

[Vaughan]

19 minutes ago, smitch6 said:

how do you purge it? i'm down there today

As I have described above.

You may have to do it twice, after topping up the system again via the pressure cap. It depends how much air is in the pipes.

[smitch6]

I have got water, yes the cold goes in the bottom and the hot or of the top,

I cracked the joint coming out of the top and let it run for a few seconds and it then seemed to get warm all the way along the pipes,

Checked the water after 10 mins and hey presto it's warm well happy now thanks everyone

[Vaughan]

If only the coronavirus had such a practical solution.