how do you drain down a calorifier?

[monkfish24]

We've got a calorifier of unknown make (i'll find out for definite tomorrow).

Whats the general way of draining it down?

 

[EugeneR]

Our calorifier has a drain at the bottom and a high pressure release valve at the top. To drain it, I turn off the main water pump, open the drain at the bottom of the tank and then pull open the pressure release valve at the top to allow air to replace the drained water inside the unit. The water drains into the bilge from where the bilge pumps take care of it.

Of course, yours may be different but I guess the general concept of getting water out the bottom and replacing it with air from the top, while keeping in mind one-way valves on the main inlets and outlets, should be the same.

 

[PlankWalker]

Most of them don't have any drain down facility,

It's normally a matter of disconnecting the cold water feed in (at the bottom of the calorifier) open the hot tap to let air in, and it should drain out at the disconnection.

If the cold feed is not at the very bottom which is normal you will be left with a small amount in the tank.

 

[bendyone]

Watch out if there is a non return valve in the system, you could thinks it's empty but it's not.

 

[macnorton]

Open taps, disconnect the feed (lower pipe) and use a wet/dry vacuum cleaner to drain it.
Work well and you can clean the bilges at the same time
.

 

[MoodySabre]

If this is to winterize it then you could look at this thread

 

[samwise]

If this is to winterize it then you could look at this thread

Interesting to read this thread , posted early October last year. Obviously they had no inkling of the kind of weather we are experiencing now. In Suffolk we were down to minus 7C last night, coldest I can remember since moving here. I wasn't on the boat last night, but I'll bet it was b*** cold! This morning I remembered that we had left a bottle of wine on board. I'm hoping there was enough alcohol content to prevent a freeze up and a very messy bottle explosion. Fresh water system etc already drained down thankfully.

 

[monkfish24]

Thank you all for your replies.

It is for winterising with a view to possibly removing the calorifier for extra space. the calorifier is fitted under the cockpit, aft of the engine and sail drive. We're humming and harring about wether to remove it and use the space for a more useful purpose like another bunk or stowage. We've had the boat for a year and a half and have never used the hot water tap for any other purpose than "ooooo hot water on a 26ft'er" We never run the engine for extended periods for it to get hot enough and we're on a mooring so can't even get shore power to the boat.

The non toxic antifreeze sounds like a better idea for the mean time whilst we decide on removal or let it be.

 

[joyfull]

How do you refill the tank and repressurise/bleed the boat hot water supply side

 

[HunterWanderer]

Most do have a non return valve at the bottom inlet connection to stop warm water flowing back. You have to remove this to let the water out of the calorifier.

Also, if you have a pressure accumulator it should be after the calorifier or else the safety relief valve will operate to relieve the pressure when the water expands as it is heated

 

[joyfull]

Yes, it looks like a non-return and/or a tap in the pipe at the bottom of the tank. The tank top and bottom supply pipes have been disconnected and the tank emptied to move it to get access aft. The engine supply pipes to the heat exchanger coil are long enough and have not been disconnected, so I presume will be alright now I have it back in place.

The question is now it is all re-connected how do I refill the tank and bleed the system. Do I just turn on the hot water taps and let it flow through or will it need priming or bleeding?

 

[Momac]

On my boat it is a simple matter of filling the cold water tank then open a tap turned to hot ............with the pump on of course.

 

[vyv_cox]

How do you refill the tank and repressurise/bleed the boat hot water supply side

Just turn the pump on and open the hot tap. Water feeds into the calorifier from the bottom, expelling all the air. Once the tap runs water it's done. On my motorhome I do this many times per year as there is a temperature controlled valve at the bottom of the water heater that dumps all the water from it when the temperature drops below about 4C.

 

[Tony Cross]

When I replaced my calorifier last year I fitted a stop tap in the cold water feed so that I can drain the tank without having to turn the water pump off so that the cold taps still function. My pressure release vale is connected to a pipe that drains into the bilge well, so to drain it I shut off the cold water, open a hot tap and cock the pressure release valve so it stays open. It's a good test of the bulge pump as well.

 

[chrisbitz]

If you decide to remove it and want to sell it, let me know how much?

thanks!