filling loop

6 May 2008
Reaction score
United Kingdom
wee bit baffled about my boiler. boiler has got zero water pressure so topped up via filling loop qasa usual but gauge isnt . disconnected the loop from the return and water is definitely flowing through loop. someone has said the flow non return valve is prob stock there not allowing minas water to enter? how can i tell if its this or a faulty water pressure gauge???
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gently tap on the pressure gauge see if needle moves rapidly.but i do not suspect the pressure gauge as they hardly fail .check both valves on the filling loop and the loop/pipe itself .valves usually fail.
Take the handle off the valve in question and turn using pliers (sometimes the handles wear and spin without actually turning the valve )
theres only one handle which is one the cold side working fine. the flow pipe only has a non return valve no handle . sorry should have mentioned that
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non return valve might be blocked.can you drain the system down and replace isolation valve and non return should be straight forward.
the pressure guage is only there to record the pressure, so if it is faulty the water will still be going into the system (then rapidly out of the pressure relief valve) so you will hear it going in, if you turn the valve on and hear nothing the non return valve will be blocked, make sure it isn't the type with a slot valve rather than a handle which you might be missing
if its the one with a little plastic handle, the handle quite often shears off. plus the pressure gauge may be faulty, doesn't take much muck to block it, ive hade this happen a few times recently. reads pressure fine before draindown, but wont repressurise, same as a blocked cold feed really. couple this with low water mains pressure which doesn't exceed 3 bar and you have the o.p's fault.

also you really need to look into why your boiler has lost pressure. did you bleed any rads or have any work done. if not, then you may have a water leak somewhere or your expansion vessel may be empty/knackered. you need to check this out.

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