Great Water Heater ? Copper lined

[goboatingnow]

Originally Posted by sailorchic34

No question, aluminum is a retched material for a water heater/calorifier.

Actually while the installations look the same, the standards used in the UK and USA are not at all the same. The UK Copper water heater has a much lower maximum working pressure, generally around 30-35 psig.

The UK pressure relief valve is sized to relief about 5 psig over maximum working pressure. US water heaters are designed for 80 psig working pressure as most all cities have 50-70 psig (or higher) city water pressure. US pressure relief valves are generally set at 100 psig

The copper water heaters require an expansion tank as the copper tank wall can not resist thermal expansion. This is the case even with a VSD water pump. On high pressure cold water (over 35 psig or so) a pressure reducing valve may need to be installed on the cold water inlet to the copper heater.

The copper heaters in the UK are used in homes and boats. In the US they should only be used in boats and don't meet US plumbing codes.

With all that said, the copper UK heaters are probably the best there is for boats.

Oh, on PEX, Just to clearify, PEX does resist freezing in that it does not break on the first few freeze /thaw cycles. It will however fail given enough freeze /thaw cycles. The PEX walls do get weaken in the freeze thaw cycle.

I was referring to boats plumbing not homes. Boats in the US and UK are all plumbed with similar equipment.

In the UK , virtually no calorifier would be used in a home , and vice versa.

Also few UK homes have closed and hence pressurised hot water , most are driven by a simple head of water from the cold water tank in the attic. You can do " high pressure" systems , but not that common in ordinary domestic houses. Hence most UK homes have no pressure relief valves on the hot water cylinders

As you you comments Re copper on boats and vsds. The existence of an accumulator is sufficient to cope with hot water expansion as there is no back flow preventer. ( in UK calorifiers )

Dave

[sailorchic34]

I was actually aware (learned that in the 80's) that the UK used atmospheric/unpressurized water heaters. Though I might expect a calorifier in apartment buildings, etc.

Agree that a "properly" sized accumulator/expansion tank would be acceptable if there were no PRV's, check valves or mixing valves in the system. If you look at the manufacturers installation instructions, you will fine that sometimes they indicate a separate expansion tank on the discharge of the water heater.

This is the case with the Solaris /SureJust units the OP was looking at BTW. Both come with a mixing valve on the hot water discharge, which requires a second expansion tank on the hot water side of the unit, per the manufacturers instructions.

I guess my short answer would be to simply read the installation instructions. The working pressure limitations of the UK units might catch a few US boaters by surprise. Knowing how much guys like reading directions and all. That really was all I was trying to say.

[DoubleWhisky]

Originally Posted by sailorchic34

I guess my short answer would be to simply read the installation instructions. Knowing how much guys like reading directions and all. That really was all I was trying to say.

And You made a good point