Filling loop to boiler in new build

Henrys Grimey Paws

Hi,

We moved into a new build last year, I can see the pressure gauge on our boiler is just above 0.5 of a bar which is the minimum pressure required according to the boiler's manual. According to the manual this can be topped up from the mains via a filling loop but I can't find out where this is!

I've been up to the cold water tank in the attic as well as the hot water cylinder but there's nothing obvious in either of these places that would achieve this. The only place that I've found that might be it is just behind the washing machine, see attached photo, the cold water outlet is attached to our washing machine but could this also function as a filling loop for the boiler? This is in the same room as the boiler so would allow me to view the pressure gauge on the boiler if it was the filling loop

If it's not obvious from my post I'm not an expert in this so apologies for any glaring errors!

https://imgur.com/a/5znw8c2

John.G

The red valve may be a hot fill for the washing machine, I would check that out first, your present machine may (probably) not have a hot fill facility but the hot fill line may still have been installed.

Henrys Grimey Paws

I expect that it most likely is a hot water fill to the washing machine as it's right beside the "place" for a washing machine, how would I go about identifying if it is a hot water fill pipe or if it is in fact the filling loop?

The cold water feed is definitely coming off the mains

John.G

Can you trace it and see if it is teed into the hot water supply.

DGOBS

Might be easier to upload pics of the hot press pipework, possibly it's been plumbed on low pressure from the header tank via a NRV, that may not be obvious to you. (not that I condone such systems!!)

John.G

DGOBS wrote: »

Might be easier to upload pics of the hot press pipework, possibly it's been plumbed on low pressure from the header tank via a NRV, that may not be obvious to you. (not that I condone such systems!!)

Yes or may have a separate F&E Tank in the attic. If it is a sealed or semisealed system then the pressure should rise to = or > 1 bar with a hot boiler/system. There're should also be a expansion vessel somewhere, if gas fired, usually integral with the boiler, if oil fired probably but not exclusively, externally mounted.

Henrys Grimey Paws

Ok went and got some photos from the hot press, the piping coming from the left hand side to the tank is to solar panels on the roof. Plumbing is pipes connecting to the tank from the right if that makes sense.

https://imgur.com/a/WgaZd4E

John.G

In the third or fourth frame down, above the SystemLink box there is a PRV (pressure reducing valve) fitted with a pressure gauge, if this is reading 0.5 bar or slightly higher (same as with a cold boiler) then you can see if the red valve above it is closed, if it is, open it slowly while observing the pressure gauge, if the pressure stays the same you may find that the black isolating valve on the PRV is a closed, LOOKING ON this knob (valve) slowly open it and see if the pressure starts to rise, if so, shut it at 1 bar and see if boiler pressure is also 1 bar.
You may find that both the red isolating valve and the PRV valve are already open, if so then the PRV is set to maintain a minimum pressure of 0.5 bar and is operating in a Auto Fill mode.

Henrys Grimey Paws

John.G wrote: »

In the third or fourth frame down, above the SystemLink box there is a PRV (pressure reducing valve) fitted with a pressure gauge, if this is reading 0.5 bar or slightly higher (same as with a cold boiler) then you can see if the red valve above it is closed, if it is, open it slowly while observing the pressure gauge, if the pressure stays the same you may find that the black isolating valve on the PRV is a closed, LOOKING ON this knob (valve) slowly open it and see if the pressure starts to rise, if so, shut it at 1 bar and see if boiler pressure is also 1 bar.
You may find that both the red isolating valve and the PRV valve are already open, if so then the PRV is set to maintain a minimum pressure of 0.5 bar and is operating in a Auto Fill mode.

Thanks for this, looks like both valves are open. The PRV valve handle has directional indicators on it for C and A, I'm assuming C is close so I guess A is autofill then?

John.G

Not sure what you mean by the handle, are you referring to the black knob?, if this is a normal type of pressure reducing valve (PRV) then it should take 3 or 4 turns to open or close it, By "auto fill" I mean that if the system pressure falls below the PRV set point pressure then it allows make up water into the system.
What is the pressure gauge reading?? and can you get a more detailed photo of the PRV or whatever it is, including the C&A, I would leave everything as is for the moment until we are sure what exactly we are dealing with.

Henrys Grimey Paws

Pressure gauge is reading 0.5 bar, this matches what's seen on the boiler gauge when it's not running.

Attached further photos of the gauge and prv here, you can see the c & a indicators on the black valve "handle"

https://imgur.com/a/SGAm0lm

John.G

Thanks, I would guess that you have a "Italian" PRV, in italy open=Aperto & Close=close (google) so if you think this is in the open position then close it, it should take 3 or 4 turns or so....then reopen it, you already stated that the red gate valve is in the open position.
if the PRV valve is in fact closed, open it slowly and see if it increases the pressure but not > 0.8/1 bar. If both valves are open (Auto fill mode) and if you want to increase the pressure you will see a adjusting screw with a lock nut on the opposite end of the PRV, undo the lock nut and very slowly turn the adjusting screw clockwise until you get the required (cold) pressure then re tighten the lockscrew. Personally I don't like the Auto fill mode because if you have even a very small leak somewhere then you will be unaware as the pressure will stay constant but you are introducing oxygen rich water into the system which will rot away your rads eventually or build up sludge. Ideally once you set your pressure, say, to 0.8 bar, then I would suggest shutting off both the PRV & the red isolating valve and just keep an eye on the cold pressure for any fall off., the system should normally only require topping up a few times a year.

You might then post the final boiler pressure when fully up to temperature with all zones open.

Henrys Grimey Paws

So that has done it! Turns out we had an auto fill system so I've done as you stated and adjusted the screw till the gauge read 1 bar. Then closed both the prv and isolating valve. The gauge on the boiler itself is reading slightly higher than 1 bar (say about 1.1 or 1.2)

John.G

Very good, just keep a eye on the hot system final pressure.