expansion tank

[dreadnought]

hi all, i,m fitting my water system on my nb, i have sited a expansion tank after the pump on my water tank, can anyone tell me if i need another tank at the calorifier ,

many thanks in advance

[Chewbacka]

Short answer - Yes

 

Longer answer - If there is a non return valve(NRV) on the input to the calorifier (which is fairly normal) then you must have an expansion vessel. Some calorifiers make it a warranty condition that you have one. - If you don't when the water heats up it expands and increases the pressure maybe high enough to flow out of the pressure relief valve. The constant cycling of pressure in the tank will greatly shorten it's life.

 

Even without an NRV the accumulator that you have is not set up for the job as it runs at a lower pressure, and so I would strongly suggest you have an expansion vessel (and NRV)

 

Suggest you have a read of the Surejust site

http://www.surejust.co.uk/expansion-tanks

 

Added

Accumulators are to even out the pump output and an expansion vessel is for the hot water. They are set to different pressures.

Edited June 13, 2016 by Chewbacka

[Tiggs]

I suggest you contact the Hotel Boat section of British Marine (formally the Association of Pleasure Craft Operators).

 

I think what you need is something like an Hotel Boat License.

[Guest]

Short answer - Yes

 

Longer answer - If there is a non return valve(NRV) on the input to the calorifier (which is fairly normal) then you must have an expansion vessel. Some calorifiers make it a warranty condition that you have one. - If you don't when the water heats up it expands and increases the pressure maybe high enough to flow out of the pressure relief valve. The constant cycling of pressure in the tank will greatly shorten it's life.

 

Even without an NRV the accumulator that you have is not set up for the job as it runs at a lower pressure, and so I would strongly suggest you have an expansion vessel (and NRV)

 

Suggest you have a read of the Surejust site

http://www.surejust.co.uk/expansion-tanks

 

Added

Accumulators are to even out the pump output and an expansion vessel is for the hot water. They are set to different pressures.

This is very similar to the advice I was given several years ago, and I fitted an accumulator in the hot water system (mine has NRV valve fitted.) IIRC the tank should be a certain percentage of the calorifier size, though the figure escapes me now. I believe it to be a far better job than not having an accumulator, in that it is kinder to the calorifier. I hear a lot of reports about calorifiers bursting and I often wonder if the reason is lack of accumulator.

[alan_fincher]

I suggest you contact the Hotel Boat section of British Marine (formally the Association of Pleasure Craft Operators).

 

I think what you need is something like an Hotel Boat License.

 

There is more than a bit about this answer I'm not understanding!

 

Are you sure you have posted it in the right thread?

[David Mack]

There's a longer version of Tiggs' post on the "how to get boat for 12 weeks" thread, which is where I suspect it belongs.