Repressurize Boiler Question: Any Ideas for this system?

jArgHA

I have a Gas Combi Boiler, it is a Volkera Mynute HE. The pressure had been dropping a bit recently and then as luck would have it, the pressure went so low on Christmas day that it will no longer turn on/fire.

I no longer have the ability to contact the plumber who fitted the works which you will see in the photo below, but re pressurizing the system is a mystery to me - I previously lived in houses where simply turning 2 black valves was all that was required.

In this case there is just 1 black valve, and also a fitting which has a removable cap with '1.5bar' written on it - and the inside of which has a black plastic inset screw/plug, which can be rotated with a 5c coin and some pliers. The other side of this fitting has a rotating gray knob.

Hopefully the photos below will describe my setup best. Would anyone have an idea on how to re-pressurize this system?

John.G

"reassemble" the valve, open the black isolation valve, slowly unscrew (anticlock) the grey knob on the end of the presuure reducing (PRV)
valve until pressure rises to 1.5 bar, if pressure doesn't rise remove the the cap right on the end of the PRV (not the whole piece that you had removed) and you should see a adjusting screw, turn this slowly clockwise) until required pressure reached, then shut the grey knob and the black isolating valve,

jArgHA

John.G wrote: »

"reassemble" the valve, open the black isolation valve, slowly unscrew (anticlock) the grey knob on the end of the presuure reducing (PRV)
valve until pressure rises to 1.5 bar, if pressure doesn't rise remove the the cap right on the end of the PRV (not the whole piece that you had removed) and you should see a adjusting screw, turn this slowly clockwise) until required pressure reached, then shut the grey knob and the black isolating valve,

You are a star sir, I will try this out soon and report back.

jArgHA

By the way, should the boiler be set to the Reset position, or does it matter?

steinbock123

Why does pressure drop over time? Mine does the same, but there are no water leaks anywhere in the house. Should the pressure, once set, not remain constant?
It seems to be worse in the summer when the heat is never switched on.

John.G

jArgHA wrote: »

By the way, should the boiler be set to the Reset position, or does it matter?

not familiar with this boiler but if it has locked out due to low water pressure then would imagine that it needs reset,

jArgHA

@John I followed your directions and there was no change whatsoever in pressure when moving the black valve and turning the gray knob slowly anti-clockwise (although this knob was previously moved by me into an intermediate position).

I then removed the internal black screw fitted plug using a coin, and looking inside the PRV can see the top of a bolt (see photo below). I have a ratchet set and fitted a 10mm socket and started turning the inner bolt clockwise as advised, but still there is no change whatsoever in the pressure gauge.

Would you expect that this bolt should need to be rotated a lot, or a little? (I turned it probably about 2 full revolutions clockwise to no avail).

Not sure if I am running out of options now or why it will not repressurize



Note : There was also what looks like a steel spring in behind the black screw plug.

John.G

steinbock123 wrote: »

Why does pressure drop over time? Mine does the same, but there are no water leaks anywhere in the house. Should the pressure, once set, not remain constant?

It could be a number of reasons apart from any leakage....exp vessel precharge (air) pressure or/and filling pressure incorrect, these would normally be, respectively, 1.0/1.5 bar which gives a ~ 2 litre water reserve to make up for any tiny leaks or rad air venting....exp vessel might be slowly loosing its pre charge pressure even through the rubber diaphragm in to the water side, the exp vessel should, theoretically be precharged with nitrogen, like aircraft tyres as its non permeable with rubber.
My relations gas fired system only drops 0.1 to 0.2 bar between its yearly services. I have a open vented system with a header tank but I keep the (ballcock) isolating valve permanently closed and since installation nearly 50 years ago I have never heard it making up into the tank on the rare occasions that I reopen it to check.

jArgHA

Just bumping my post above with update, in case it got lost in the mix.

Lenar3556

jArgHA wrote: »

Just bumping my post above with update, in case it got lost in the mix.

1. Check that the black valve (in 2nd photo of your first post) is definitely open. Note it is in the closed position in the photo. This is the incoming mains supply.

2. Check that the grey hand wheel on the end of the filling valve is definitely open.

Once both of these are open, you should hear water flowing and see the pressure increasing.

If not, the possibilities are;
1. No mains water coming into the filling valve via the flexi pipe. (Unlikely if the black valve referred to above is open)

2. Filing valve has seized - most likely. You could try a few firm taps of a spanner to the brass body in the hope of freeing it. Otherwise it will need to be replaced.

3. You have adjusted the pressure setting nut such that it is not allowing any flow - these are usually factory set at 1.5 bar and shouldn’t require adjustment. (In the circumstances you could try some minor adjustments to it again - watch the pressure on the gauge, 1.5bar is loads. Be prepared to shut of the black valve referred to previously as soon as this is reached, or in the event of any leak.)

John.G

You shouldn't be touching anything inside the PRV as that is the diaphragm assy, as i said re assemble it and at the end where it says 1.5bar, either rotate the knurled part clockwise to increase the pressure or there might be a adjucting screw under the label.

Mabe first check......
With it dis assembled (ensure black isol valve off) hold the adjustment body and rotate the blacxk knob or whatever and you should see a threaded "bolt" moving in/out of this adjustment body, this (when reassembled) presses on the internal diaphragm assy and allows more water in...then carry out the above with both black isol valve and the grey valve fully opened and see how you get on. (maybe some other isol valve upstream of the black isol knob)

Wheety

Do you have a pump on the system too? Kicks in when you use hot water?

We have the same valve on ours and we just need to open the grey knob. Then run a tap (not the mains supply in kitchen tap). That should kick the pump in which will repressurise the boiler. I don't think the boiler demand is enough on it's own to get the pump working.

Actually doesn't look like you have a pump before that valve so forget all that

John.G

Could be a pumped system, this is a fairly standard PRV attached.

John.G

Looking at that again, re insert the spring under the plastic "adjuster" where shown and turn this clockwise until pressure increases but you shouldn't have had to remove the end piece at all originally.

jArgHA

John.G wrote: »

You shouldn't be touching anything inside the PRV as that is the diaphragm assy, as i said re assemble it and at the end where it says 1.5bar, either rotate the knurled part clockwise to increase the pressure or there might be a adjucting screw under the label.

Mabe first check......
With it dis assembled (ensure black isol valve off) hold the adjustment body and rotate the blacxk knob or whatever and you should see a threaded "bolt" moving in/out of this adjustment body, this (when reassembled) presses on the internal diaphragm assy and allows more water in...then carry out the above with both black isol valve and the grey valve fully opened and see how you get on. (maybe some other isol valve upstream of the black isol knob)

Success! I have the pressure up to 1.5 now - I was turning the wrong thing clockwise on first attempt, but figured it out now. Thanks a million for the help it was a life saver!