Hot Water 3kw heater???????????????????????????

[Nat]

Here is one for the Panel.
Problem is my boats hot water system is run from the engine via calorfier.(no immersion heater fitting) Now this is all very well when on a cruise as nice hotish water is available at the end of it. & stays hot/warm for 15hr,ish. Problem is when in port I need to run engine at 2000rpm for about 45 mins to get warm water. This is 1. annoying to next berth 2. annoying to me & 3. bloody expensive. Boat is raw water cooled by the way.
Alternatives are convert one engine to fresh water cooling which should make calourfier more efficiant. or fit a 3kw instant hot water shower in toilet/shower cubical to run off shore power (16amps) which is the simplest & least expensive option.
Questions is Do the 3kw heaters draw more power on initial start up as this may trip the breakers or has anyone got any other suggestions.....Nat

 

[Brayman]

An alternative but probably expensive is to fit a diesel powered water heater (eg eberspacher Hydronic), then you can have hot water when you like

It entails replacing your engine water hoses with ones from the heater and is also used instead of your engine when cruising, otherwise you would need to fit a twin coil calorifier to have the best of both worlds.
3kw is pretty heavy duty for marinas I'd think.

 

[Andrew_Fanner]

Why not have an immersion heater coil in the calorifier?

 

[brianrunyard]

3Kw instant shower isn't going to give high flow rate of hot water. Domestic instant showers are in the region of 8Kw.
Why not fit an imersion heater, that way you've got hot water for washing as well as the shower.

 

[Nick_H]

Agree with others, replace calorifier with one that has an immersion, or if poss have yours modified

 

[Nickcf]

Most marina shore power supplies are protected by circuit breakers with a B or C curve rating which allows for 5x surge or 8x surge eg they will be marked B16 or C16. I think the most common will be a C rating so surge from shower heater shouldn't be an issue.

Alternatively why not fit a 1kW immersion in the calorifier so that you can leave that on and still use a (small) kettle or battery charger etc?

 

[dragoon]

Definately go for the immersion heater. I put a timer switch on ours so that you push a button and it comes on for 20minutes. This is enough time to get piping hot water without accidentally being able to leave it on.

Cheers,
Paul

 

[Hurricane]

Our boat is fitted with two small immersion heaters.
I think they are about 1.5KW each,
This means you can run on a low power supply.
I use them regularly.
I was on the boat last night and used the immersion heaters then - both in fact.

 

[Nat]

Well after reading most replies it looks like Im going to have to bite the bullet &
buy another unit, The one thats fitted has no provision for a immersion heater & is glass lined so no chance of fitting one. Does any one think converting one engine to freshwater cooling may solve the problem as I have a brand new heat exchanger laying about doing nothing. At moment both engines run cool with raw water cooling about 150 degrees tops with present thermostats. I think this is why the water takes so long to get hot....Nat

 

[davedpc]

I think my immersion heater is 1k and set very hot which will give more when mixed with cold. The elec. jug is 2k and with all3 inc. the charger switched on together doesnt blow a plug top fuse. [13amp total supply to boat] Dave.

 

[Cliveshep]

There used to be a fitting called an "Essex Flange" you could use to create an immersion heater boss, any plumbing sorts here might know if it's still made or you can ask at a good plumber's merchants. You cut a hole in your copper cylinder and installed this thing through the hole and then fitted an immersion into it. The coil in a calorifier generally goes around the outside of a cylinder, so clear of a top hole but you'd better check by looking down the top tapping with a torch before cutting holes!

 

[carlton]

Best option is get a plumber to fit a 1KW immersion element into existing tank. Watch out for the "worm" inside the calorifier.

Must be fitted at/near the bottom. If fitted near the top of the tank it will only heat the water at the top.

Or just buy a new calorifier complete with 1KW immersion.

 

[Nat]

Thank you all

Thank you all,
Sometimes it helps to have valuable input to make the final decision & that is to replace existing calorifier for one with immersion heater, I especially like Dragoons idea of timer switch & will fit one. Once again thankyou all.....Nat