JAGUAR combi boiler

[daveinashford]

My boiler has been losing pressure. Please bear in mind I'm no plumber, so if I describe things badly or use the wrong terms I'm sorry!

It did the same thing a while ago-it would lose enough pressure to shut down-filling it with the filling loop fixed it for a short while (a few minutes), before the pressure dropped right down again. This was sorted out by bleeding the radiators, then the pump, then re-filling. This time these steps have not solved the problem.

Water is coming out of the PRV outlet. I have turned the PRV round a few times, but it's made no difference.

I understand these symptoms may indicate a problem with the expansion vessel, and that this can be tested by pressing in the valve to see if air or water comes out. The problem I have is that I CAN'T FIND THE PRESSURE VESSEL! Supposed to be a big red thing, but there's nothing like that visible. I've got the front off, and the cover under that off (so the only cover left on the main part is the one directly over the heat exchanger and gas bits. Still can't see it.

It's the same boiler as in this thread.

The only other thing I noticed was a load of cack around the bleed valve on the motor. Like deposits from water (we have VERY hard water here!), but it's dry.

Does anyone have any suggestions, other than 'replace the boiler, it's rubbish'?

 

[AkuraEngineer]

the expansion vessel is located to the rear of the boiler you can acess it from the top of the boiler below the flue behind the boiler

what do you mean you have turned the prv round?
are you sure your filling loop is not letting by?
what pressure are you topping it upto?

if you keep loosing pressure you must have a leak somewhere it may even be the PRV it self that cuasing the pressure to go down

 

[daveinashford]

the expansion vessel is located to the rear of the boiler you can acess it from the top of the boiler below the flue behind the boiler

what do you mean you have turned the prv round?
are you sure your filling loop is not letting by?
what pressure are you topping it upto?

if you keep loosing pressure you must have a leak somewhere it may even be the PRV it self that cuasing the pressure to go down

Access to the top of the boiler is a bit restricted, so I hadn't looked there. Will do.

I read somewhere that if the PRV is dirty or blocked in some way, turning the red bit round can free it up.

Letting by? Not sure what that meansl; leaking back into the water pipe?

I have been topping it up to 2-3 bar.

 

[onlyfitidealboilers]

get a new boiler these are crap. simples

 

[daveinashford]

the expansion vessel is located to the rear of the boiler you can acess it from the top of the boiler below the flue behind the boiler

Thanks, Akura. Still not easy to get to given the location of my boiler, but do-able.

No pressure in it at all, but no water coming out. I've pumped it up, so I'll just have to wait and see if it holds the pressure.

(I'm still going to start putting pennies in a jar labeled 'boiler replacement fund' though! )

 

[rojaca]

1. LETTING BY- Water passing by the valve when it should be shut. either faulty valve or debris under the seating.
2. Top up to 1 -1.5 bar when cold. The pressure relief valve will operate at three bar. the pressure of the htg system should not reach three bar under normal operation.
3. There is a specific procedure for recharging your expansion vessel. Have a look in the faqs regarding this as you may be getting a flase reading on the pressure of the vessel.

Jaguars aren't too bad for a budget blr. So if it is just the vessel has lost it's charge I wouldn't be getting ready to have it pulled of the wall just yet.

 

[Agile]

I agree that they are very simple and reliable boilers.

Pity there were not more of them installed!

Tony

 

[Alfredo]

If it drips from the Pressure Relief Valve (outside) when boiler is cold and you have topped the pressure up to 1.5 bar then the PRV is at fault. It may just be dirt on the seating allowing water to get past (letby). You can dismantle and clean some PRVs, but not all.

If it doesn't drip when cold but drips when hot, then check the pressure gauge. If its reading anything up to 2.5bar and the PRV is losing water, then its the PRV again.

If however you see the pressure heading up to 3 bar, then the PRV will run water as thats its job, and then you need to find the pressure vessel as there is a fault there with no pressure.

When you find it...there will be a schrader type valve (car tyre type). They are not always easy to access. If you briefly press the car tyre valve, if water comes out your pressure vessel is knackered (failed diaphragm) and has to be replaced. Otherwise, when the system is Cold and drained, you need to ensure there is about 0.7 to 1 bar pressure in it, and that it is holding that pressure. Use a simple car tyre foot pump (mine cost £1.99..). If the valve leaks, then you need to put a new valve insert in..about £1, plus a little tool to remove it from Halfords or tyre shop

It might end up being a boiler off the wall job if the pressure vessel needs replacing. If so get a professional in is my advice.

Alfredo