pressure relief valve

[larson250]

Are the pressure relief valves on a calorifier tank the same as domestic hot water tanks?
Mine lets go (to coin a phrase) before the water pump switches off.

Regards,
Dean

 

[nedmin]

Yes they are. They dont usually "let go" sounds like your pump is not cutting out soon enough.Dont know what pump you,ve got but most have an adjustment screw at one end.Mine goes ACWise to reduce pump pressure.Its possible the PRV has stuck.If you rotate the red knob on the end it will cause the PRV to vent the
pressure.Rotate again and you will feel it "drop in" again and reseal.My PRV is 3 Bar.

 

[savageseadog]

Slightly random input because I don't know anything about boat calorifiers but do know about unvented hot water tanks and the valve could well be the same. The pressure relief valves on those are temperature operated too and they do go wrong. I had one that released at too low a temperature.

 

[larson250]

Hi,
Thanks for the replies.
I too think that the pump is not cutting out soon enough and I have tried to contact Shurflo to see if there is any adjustment.
As for the temperature side of things I have hopefully added a picture of the said item.
I don't know what the pressure setting is, as there are no markings.



Hope this helps,

Dean

 

[TrueBlue]

They can be a cheapie item - so not very well designed.
IME they do get furred up and turning the knob on the top several times can clear the gunge (calcification), or blow out any loose muck that may have floated to the top.

However, any blockage only results in a dribble, not venting a lot of water.

If accessible they are easy to dismantle and clean, and at the same time you can see if the spring has broken.

Not an expensive item if reasonable standard. The better plumbers merchants usually stock them - or even eBay....

 

[larson250]

Sorted this weekend. I turned the pressure down on the pump.

Thanks all,
Dean