Calorifier expansion tank

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seaangler23

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The very old calorifier started leaking so it’s been pulled out and got a new surecal 30l horizontal to fit, the old system never ran an expansion tank on the hot side not did it have any mixing tap so was very hot, never had any leaks.
The new surecal instructions say I need a 5l one but is it nessasery? I have a pressure reservoir on the cold side so surely unless there’s a one way valve in it this will do the same thing, there is a pressure blow off to the bilge on it as well.
Got a big trip in a week and a load of things to sort and not enough time to be messing about
 
seaangler23 said:
The very old calorifier started leaking so it’s been pulled out and got a new surecal 30l horizontal to fit, the old system never ran an expansion tank on the hot side not did it have any mixing tap so was very hot, never had any leaks.
The new surecal instructions say I need a 5l one but is it nessasery? I have a pressure reservoir on the cold side so surely unless there’s a one way valve in it this will do the same thing, there is a pressure blow off to the bilge on it as well.
Got a big trip in a week and a load of things to sort and not enough time to be messing about
Click to expand...

There should be a non return valve between the cold water and hot water systems so that the pressure increase as the water in the hot system expands does not force hot water back into the cold water system. The expansion tank will absorb the expansion of water in hot water system without forcing the relief valve to open every time the system heats up.

Every thing is explained here: https://www.jabscoshop.com/files/Accumulator and Expansion Tank Instructions ZPWL4 doc595.pdf
 
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I've done away with the non return valve on the calorifier. The hot water doesent actually get back to the cold tap and it means you dont need another expansion tank. It also makes it much easier to drain the system for the winter. Just check the operating temp of the water pipes.
 
I have an expansion tank/accumulator immediately after the pump but not one after the calorifier. Provided the Tee in the cold water supply to the cold taps and the calorifier is more than a couple of feet before the calorifier there is no need for a NRV as the expansion of hot water cannot reach that far back.
 
that’s my thinking, as I haven’t found a nrv, the pressure should back up but the heat never seemed to migrate to the cold tap, old calorifier was dangerous as you could make tea with the hot water, the system won’t wont see tgat kind temps now, , il give it a go and monitor the pressure release, accumulator seems like a winter job to me��
 
seaangler23 said:
that’s my thinking, as I haven’t found a nrv, the pressure should back up but the heat never seemed to migrate to the cold tap, old calorifier was dangerous as you could make tea with the hot water, the system won’t wont see tgat kind temps now, , il give it a go and monitor the pressure release, accumulator seems like a winter job to me��
Click to expand...

Surecal calorifiers are fitted with non-return valves.

The water within the calorifier will be the same temperature as the old one when the engine is running, but because of the mixer valve it will be at a lower temperature at the tap.
 
Cheers il have a look at it later, may see about removing it to get us going, too many things to do and not enough time or money to do it, and that’s me been working towards this trip for a year
 
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