Calorifier pressure release .How many Bar valve should be fitted ?

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oldgit

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Pressure release in calorifier venting when Sureflo pump is turned on to pressure system from cold..
Working perfectly OK, until wife half way through her shower :(
Bought new one specifically for boat system, 3 Bar but same problem.
Do I need something with higher bar rating ?
What should the rating be for a marine system.


a quick search of the interweb suggest pump pressure switch is not turning off pump and over pressurising the system ?
 
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You should fit the same type / rating as the original. It may be a combined pressure and temperature relief valve

It should open at a little above the pump cut out pressure. Check what this is supposed to be from the pump model data. Maybe it is not cutting out at the specified pressure.

Maybe your expansion tank is not absorbing the expansion, when the water reheats although this is unlikely to be an issue while hot water is being used. Check and re-pressurise the expansion tank if necessary.

Check also that it is not lifting due to the water heater over heating the water.. you might not realise if your calorifier has a thermostatic control valve to control the water temperature delivered to the taps etc


Why is the fact that the relief valve is lifting, presumably only briefly, causing any problem ?
 
Our overflow is taken to a 5L plastic can and needs emptying once a week as it lets off a bit after every shower replaces the hot water via the immersion. If we run the engines it can fill the bottle in hours so we make a point of a) emptying the bottle regularly especially before running the engines and b) not leaving the immersion heater on 24/7 on the boats we had in the USA the ovrerflows were taken to an shower drain collector sump with built in automatic pump to empty overboard as needed, aircon and fridge drains went same route..

I have to say I too wonder if a higher pressure relief valve is needed, but right now there are other priority jobs and it is too hot

BTW we have had Shurflo pumps previously that could be adjusted to reduce pressure applied IIRC by an adjustment screw on the end under a plate with makers label on
 
Robin said:
Our overflow is taken to a 5L plastic can and needs emptying once a week as it lets off a bit after every shower replaces the hot water via the immersion. If we run the engines it can fill the bottle in hours so we make a point of a) emptying the bottle regularly especially before running the engines and b) not leaving the immersion heater on 24/7 on the boats we had in the USA the ovrerflows were taken to an shower drain collector sump with built in automatic pump to empty overboard as needed, aircon and fridge drains went same route..

I have to say I too wonder if a higher pressure relief valve is needed, but right now there are other priority jobs and it is too hot

BTW we have had Shurflo pumps previously that could be adjusted to reduce pressure applied IIRC by an adjustment screw on the end under a plate with makers label on
Click to expand...

But why is the expansion not being absorbed by the expansion tank .... that's what they are for.
 
When pump is turned on via main fuse board , irrespective of water temp, the valve instantly opens constanty venting water over the side.
Turn pump off, valve shuts !
Suspect that both old and new valves are OK and that pressure switch is faulty or needs adjustment.
To boat today with my set of alan keys......
 
oldgit said:
When pump is turned on via main fuse board , irrespective of water temp, the valve instantly opens constanty venting water over the side.
Turn pump off, valve shuts !
Suspect that both old and new valves are OK and that pressure switch is faulty or needs adjustment.
To boat today with my set of alan keys......
Click to expand...

Ah yes. I misunderstood your original post.

Thought you meant its OK but always opens when wife half way through her shower ... Wife showering a bit of a red herring.

Id blame her but I guess she will say:

RH%2081_zpsxga1gfxz.jpg
 
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oldgit said:
Pressure release in calorifier venting when Sureflo pump is turned on to pressure system from cold..
Working perfectly OK, until wife half way through her shower :(
Bought new one specifically for boat system, 3 Bar but same problem.
Do I need something with higher bar rating ?
What should the rating be for a marine system.


a quick search of the interweb suggest pump pressure switch is not turning off pump and over pressurising the system ?
Click to expand...

I have a Seaward calorifier that is no longer made. The Pressure Relief Valve that was sold by Aquafax is a rebadged product made by WattsWater http://www.watts.com/pages/_products_details.asp?pid=805 The pressure for the one I have is 5.2 bar so yours may be letting pressure out at too low a pressure. But of course you need to identify the right specs for your valve

TS
 
Hi

I haven’t come across an example of these domestic water systems lifting the relief valve, to be honest....unless the valve is slightly off its spring cam (if you know what I mean).
What I can tell you is....that in general engineering terms...a relief or safety valve of most systems should lift at 10% above the maximum pressure of the system. Your pump (jabsco or similar) should be marked with its max pressure.
 
Be careful of increasing the pressure. I fitted a new 3.5 bar valve with a Seaflo 3 bar pump. Two seasons later my calorifier developed a leak. This was the type similar to a domestic cylinder, just shorter.

Upon removal I found the concave base had become convex where the pressure had gradually forced the tank to expand, eventually leading it forming a small but fatal split. The replacement is rated at 5 bar. My pump is set a couple of turns below the point where the relief valve lifts. The original relief valve was corroded so I couldn't read its rating but the original pump was pathetic so likely less than 2 bar.

A small all pump achieves a better flow when paired with an accumulator at a higher pressure than would be found in a domestic set up. At home the supply is continuous at around 1.5 - 2 bar, whereas a small pulsating pump with a narrow inlet from the storage tank needs to put out a higher pressure to get a decent flow at the tap. That said the shower on my boat is far better than those at home.

Interestingly earlier this year I had a situation where scalding hot water started blasting from the cold taps, and sometimes there was a blow of steaming hot water from the relief valve. This I found was due to a completely scaled up and jammed open NRVv on the cold fill to the calorifier. I reckon I could have run a turbine on it ! A significant reason for this was due to the way I had positioned the thermostatic reg valve on the new calorifier, this was causing a pocket of air within the calorifier, so some of the heater element was not immersed, this was creating the pressure source. Repositioning the reg Vv resolved the issue.
 
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