Installing a calorifier

[DeanS]

I've inherited a twin coil calorifier. I'd like to get it connected to the engine.....without connecting anything to the coils for now.

 

Do I....

 

The engine has 2 pipes which have been kinked and tied off with straps, until such time as a calorifier is installed.

The calorifier has. (if memory serves correct)

 

1. an Inlet and outlet

2. A coil inlet and outlet

3. Another coil inlet and outlet.

 

I presume the engine pipes connect to one of the coil in/outs ?

I presume a cold water supply from the boats water tank...needs to connect to the calorifier inlet

I presume a hot water pipe going to boat hot water taps should be installed.

 

It's early in the morning....sorry if my mind isn't thinking clearly

 

 

I already have a gas heater for water, so want to use isolation valves to choose where I get hot water from.

 

Previously someone mentioned it's best to use a heat exchanger...what would that be for, and where would it be fitted.

 

I have some radiators which I'll install on the last coil circuit LATER.

 

At this point I just want to get the calorifier in place, storing water, which is heated up by the engine, and a way to get that water in and out.

 

 

THANKS

 

[Murflynn]

The calorifier IS a heat exchanger.

Connect inlet to the cold water supply, preferably with a non-return valve before the connection, and ideally with an accumulator between the NR valve and the calorifier. This will help to avoid water bleeding off from the relief valve.

Connect the engine pipes to one coil (in the case of a vertical calorifier connect to the lower coil, and ensure the engine water circulation is from bottom to top).

Connect outlet to your existing HW system with an isolation valve.

All logical really.

Edited August 5, 2014 by Murflynn

[DeanS]

Thanks so much.

That's what I needed ...a poke in the right direction.

[Scholar Gypsy]

NB the pressure relief valve is v important, otherwise something will break/explode when the water heats up.

ours empties into the drain on the washbasin.

 

I would also suggest adding a thermostatic mixer valve to mix hot water

coming out of the calorifier with cold water, to produce nicely warm water.

this greatly reduces the risk of scalding (depends on your engine operating temp of course).

well worth about £20.

[system 4-50]

Some calorifiers (maybe all) are happy to have the heat source pipework installed and up and running before the fresh water side, and vice versa, which can be convenient. The manufacturer can confirm. Surecal are very helpful.

NB the pressure relief valve is v important, otherwise something will break/explode when the water heats up.
ours empties into the drain on the washbasin.

Nah. The expansion vessel should take care of this. The PRV is for emergencies such as failure of the EV. It should not operate routinely.

Edited August 5, 2014 by system 4-50

[The Bagdad Boatman (waits)]

It is important to ensure that hot water from the calorifier cannot enter the gas heater, as the gas heater heats water by x+ degrees no matter what tempreture the incoming water is. I had a set of isolator valves so cold water could only flow to the calorifier or the gas heater.

[DeanS]

It is important to ensure that hot water from the calorifier cannot enter the gas heater, as the gas heater heats water by x+ degrees no matter what tempreture the incoming water is. I had a set of isolator valves so cold water could only flow to the calorifier or the gas heater.

 

if I have a T Piece where the 2 hot water supplies meet....(outlet of gas heater meets outlet of calorifier) should I have an isolator on the gas heater outlet. Should I have an isolator on the calorifier outlet?

 

 

or is that overkill.

Edited August 5, 2014 by DeanS

[David Mack]

 

Connect the engine pipes to one coil (in the case of a vertical calorifier connect to the lower coil, and ensure the engine water circulation is from bottom to top).

 

Top to bottom surely!

 

 

if I have a T Piece where the 2 hot water supplies meet....(outlet of gas heater meets outlet of calorifier) should I have an isolator on the gas heater outlet. Should I have an isolator on the calorifier outlet?

 

 

or is that overkill.

 

Replace the T piece with a 3 way L-port valve such as this , which you can use to select between the two hot water sources.

Do not use a T-port valve, which can connect both sources to the taps.

[Murflynn]

 

Top to bottom surely!

 

 

 

yes, on reflection that seems right. The water cools as it passes through the coil, so it tends to sink. Thanks.

[DeanS]

thanks for all the info....

 

 

Am I correct in thinking that.....once a calorifier is full..the water in it (lets say 60litres) sits and heats up when the engine circulates through the coil. Then, ...by opening a tap in the shower for instance...the hot water in the calorifier is simply pushed out....and replaced...by the incoming cold water from the boat water tank.

 

Why doesn't the new cold water entering, simply not cause the overall temp of water sitting in the calorifier...to drop...suddenly.....is it because incoming new water...doesn't just get sprayed into the holding chamber...but is always pushing down the incoming pipe....

 

if you get my meaning?

Edited August 5, 2014 by DeanS

[system 4-50]

The water stratifies with the cold at the bottom. The take off is always at the top.

[Scholar Gypsy]

yes, on reflection that seems right. The water cools as it passes through the coil, so it tends to sink. Thanks.

as the water is pumped (by the engine) through the calorifier, I think it would be more efficient (in terms of maximising heat transfer) for the water in the coil to flow bottom to top. but the effect is likely to be marginal. (I need to revise my thermodynamics)...

[David Mack]

as the water is pumped (by the engine) through the calorifier, I think it would be more efficient (in terms of maximising heat transfer) for the water in the coil to flow bottom to top. but the effect is likely to be marginal. (I need to revise my thermodynamics)...

The most efficient heat exchanger configuration is when the two flows are in opposite directions (counter flow) i.e. the incoming hot coolant from the engine is used to top up the temperature of the nearly hot domestic water, while the cooler coolant preheats the cold incoming domestic water. So domestic water in at the bottom and out at the top, engine coolant in at the top and out at the bottom.

[Scholar Gypsy]

The most efficient heat exchanger configuration is when the two flows are in opposite directions (counter flow) i.e. the incoming hot coolant from the engine is used to top up the temperature of the nearly hot domestic water, while the cooler coolant preheats the cold incoming domestic water. So domestic water in at the bottom and out at the top, engine coolant in at the top and out at the bottom.

Thank you. as I say, revision needed .....

[smileypete]

Some relevant advice on a recent topic, concerning PRVs, expansion vessel, non return valve:

 

http://www.canalworld.net/forums/index.php?showtopic=68089

 

If the calorifier doesn't have a PRV fitted or any info about max rated pressure, then a 3 bar one should do, never seen a boat calorifier rated less than that.

 

cheers, Pete.

~smpt~