- Low water pressure on a combi boiler.
A freind has had the on call plumber out repeatedly lately due to low water pressure on the boiler,the boiler reapeatedly needs topping up,no evident leaks are visible.
They just refill thew boiler and on there way they go.
How much water does a boiler hold, and any reason for loss of water pressure.Posted 4 years agotakisawa2Subscriber
Is there any water dripping from it’s overflow pipes ?
Top up the pressure, knock off the heating & close the flow & return stopcocks. Monitor the pressure for a while. Would possibly indicate if the leak is at the boiler…
This aside, they need to insist the system is fixed properly.Posted 4 years agoeasygirlSubscriber
Find out where the blow off valve pipe is, usually a 15mm pipe through the wall, zip tues a plastic bag to the end.Posted 4 years ago
If yiu go back a day later and see water inside will be a faulty pressure relief valve
If its not that the diaphram on the vessell could be ruptured, so when the water gets hot and expands, its nowhere to go, and lifts the pressure relief valve
If its a faulty valve they usually drip, if its a faulty diaphram, it will be more suddentrail_ratMember
What they said.
My expansion vessel pressure got low and blew the prv . Was told it would likely need a new prv ( in a phone call to my uncle the heating engineer)) and low and behold i need a new prv…. Once triggered they tend to fire lower and lower…..on my boiler anyway. Now it fires at 1.5 bar instead of 2.5 bar…. Although if any heating engineers want to contest that im all ears.Posted 4 years ago
Can they not monitor the pressure and top up the system themselves when required, rather than calling a plumber and waiting for them to come and sort it ?
It’s hardly a complicated task, and it would save them a lot of hassle
No ,due a disability and being in a wheelchair and not being able to reach it.
When it reaches a low presure it cuts out so no heating or hot water,not nice if youre in a wheelchair.Posted 4 years agotrail_ratMember
“If nothing leaking or dripping.then it willdefo be the the fill up valve not shutting or sealing off proply then the water in system leaking backwards through the fill up loopy thing. not a plumber and drunk.”
Good job you added that last bit because its about as definantly that as my walls are definantly green* it might be that but i doubt it.
* they are magnolia.Posted 4 years agosamuriMember
As above, we had the valve blow and it was going undetected for months before BG finally sent someone with more than two braincells.
We’ve also had a slow pipe leak but because it was leaking out slowly over plasterboard, it dried out fast enough not to be noticed for ages.Posted 4 years agomick_rSubscriber
I think Trail Rat is right about the fill loop:-
Aren’t fill loops a removable key or flexi hose and ALWAYS had to be disconnected after fill??? I thought WRAS reg was there deliberately so there was no chance nasty heating water could back fill the drinking supply? Also, the mains water is higher pressure than the heating circuit, so how could it ever leak that way?
My money is on pressure relief valve, possibly but not always related to pressure vessel failure (mine weeped just by using it to remove pressure to work on a rad without ever “going off” due to over pressure). Or a small leak somewhere else – it must only be a weep somewhere as it obviously holds pressure when they refill the thing. Not a lot of water loss is required to drop the pressure (just the amount used to move the diaphragm in the pressure vessel plus compress any air in the system).Posted 4 years ago
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