Been thinking about the Water Calorifer which will be 12 this year, works absolutely fine (touch wood!!!), but have never done anything to it and not sure if the previous owner did anything to it either. As Harry Houdini would say, it is rather difficult to reach! So is there anything I should be doing as part of my annual maintenance plan (if so, what?) or is it best left alone?

Also does anyone have the capacity size, make and spec for the type of Calorifer installed by Parkers? Also, what is the wattage of the mains A/C immersion element installed inside the calorifier?

Comments welcome.

Thanks Stuart

Pegasus 325/37

20L WATER STORAGE HEATER VERTICAL (Inc Z/TPRV Pressure relief Valve) Part No CWB21-V3

Optional 240V IMMERSION HEATER 1.25 kW Part No CW278

From Cleghorn waring

http://www.jabscoshop.co...-systems/c-warm-heaters/ 

Also, very important to drain the whole freshwater system when there is danger of frost. There are at least two methods which are described in the archives.

Mike Lockwood

Lucky Devil

Parker 325/35

It is very inconvenient as I am on a trip. Any ideas?

Mike

Shemar

Good luck

Martin

335/50 Tringa

Perhaps I should investigate further do you think?

John

Nosey 325/26

It may be that the pressure relief valve is faulty. Or I wonder if the freshwater pump could be faulty. I hear the sensor switch often goes wrong and maybe it keeps charging the calorifer? But I don't really know how they work. At least it will make me look at the calorifer. I have never even seen it as it is under a false floor in the cockpit locker. I presume this is where yours is.

Mike

Cheers Malcolm

Succes and have a nice trip!

John - my pressure relief valve drains through a pipe into the rudder rod box, thence out to sea. Good in principle, but not when it started releasing constantly and began to rot the wooden drip tray on the inside face of the transom, so...

Mike B - the helpful people at Penguin Marine down the road on Hayling advised removing the PRV and soaking it overnight in vinegar, this improved things, but not completely cured it, so...

Malcolm - I bought a new PRV, I found it is not easy to get exactly the right temp and pressure but something close should do it, but it took a while to come and while I was waiting...

Mike B again - I had the brainwave of replacing the little Whale flow switch next to the FW pump, which I had thrown away a year before when it stopped the whole system and I thought it wasn't important. Turns out it was, and it was by far the cheapest and easiest replacement of the lot. No idea why you need this as well as the pump, which only switvches on at low pressure, but it turns out it was presumably over-pressuring the system. WHen I had the pump on and hot water at the same time (engine or immersion) the PRV was delivering a cup of scalding water onto the rudder box every hour or two, and sometimes into the bilges as well.

Since then, no problems (or none that I have found yet) and I have been doing a lot of motoring...

Good point about a prv next to the water pump. I shall check to see if I have one - I've never noticed one.

Since I've put the overflow bottle in I can see exactly how much (hot) water I lose. I think it happens motoring though - I don't even have to run the pressurised water system.

By the way, we're having a soft southern version of your Scottish weather down here.

Cheers, John

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By the way, I have a new water lubricated propeller shaft seal since last winter, as part of the project to solve the vibration problem.

I had to look up Tobermory on Google Maps . I remember the name from articles in Yachting Monthly and I now have refreshed my memory: it’s on the Isle of Mull. Mike B send me the link of your voyage around the UK, so I read about your experience. Great reading. I still have to get started sailing at sea …

I am planning on removing the PRV. But how to drain the calorifer? I thought of disconnecting the cold water feed from the calorifer. But people say that there is a non return valve in the calorifer which will prevent it draining? How did you remove your PRV Peter?

Also, I don't have a whale flow switch on Shemar and the calorifer has worked well for 20 years. What is this? I tried googling it but not much luck. Should I have one?

In the cupboard under the sink you have the remove the bottom shelf. There are two copper pipes that are connected to the cold (blue) and warm (red) hose that go to the tap. Disconnect the blue hose from the copper pipe and drain the calorifier in a shallow beaks until it is empty.

This is part of my preparation for the winter.

So my plan is now to replace the freshwater pump. However, I don't understand Peter's suggestion to have a Whale flow switch. Is this something to do with the pump pressure? Can anyone shed light on this?

If the pressure switch is not working properly, but the pump itself is fine, adding an additional switch may be cheaper than replacing the whole pump. Of course this extra switch needs some available space under the wash basin in the heads.

My advice would be to first remove and inspect the FW pump and check the switch. These pumps can be open fairly easy to inspect and replace solely the switch. I’ve done it successfully in my previous boat.

In Surprise the FW pump is a Flojet pump. The switch off pressure is 1.3 bar according to the label. In this Youtube channel you can see how to replace only the pump switch:

In case of a complete pump replacement many other pumps can be fitted as they are very much alike, just match the max flow rate and closing pressure.

Many thanks to all who contributed. It has been an interesting experience and at least I got to investigate my calorifer and the PRV - which was doing the job it was supposed to!