ASHP low pressure help pls

[canalsiderenovation]

Non technical description....I noticed today that the black needle thing is pretty much on zero but the bar seems fine. I think the black one is to do with the heating. I know I need to look at adding pressure but any youtube vidros say I should have two valves and I only have one (the black one to the right). If I turn this nothing happens. Is there something else I need to turn as well? There are two blue lever things to the right.

 

 

 

 

[canalsiderenovation]

The heating has tripped in and it has creeped up a bit to about 0.5 bar but it seems if the heating goes off it drops again.

 

Edit. Spoke to soon, heating still on and it fluctuating between 0.5 and lower. If I manually turn on hot water programme (it is normally on a timer) black needle drops rapidly to zero.

Edited Thursday at 23:13 by canalsiderenovation

[Russdl]

I’m no expert. The red pointer is just a marker for where the black pointer should be. Clearly the pressure has dropped. 
 

I can’t see clearly in the video but on the right hand side of the flexi hose, that looks like an isolation valve. Is that open? Slot in line with the valve not across the valve?

 

With that open then slowly opening the black one you mentioned should allow water through and the pressure should rise. 
 

Stop when the black pointer is in line with the red pointer. 

[Russdl]

Somebody smarter will be along to give better information I would hope. 

[canalsiderenovation]

This you mean..

One side of flexi hose this..

 

And the other side this...

 

 

Just checked it now and it is back to normal but this could very well be as the heating is on but if I turn the hot water on it slowly drops so I probably need to investigate tomorrow as something is not quite right.

 

Will it do damage having the hot water heating up with the black needle on 0?

 

Edited Thursday at 23:47 by canalsiderenovation

[Russdl]

So, to re pressurise the big red expansion vessel you need to open the silver isolatation valve (second photo) with a screwdriver (90 degree turn either way, doesn’t matter, it’s open when the slot is in line with flexi hose). 
 

Then turn the black handle lever thingy (first photo) to slowly open it and you should see the pressure increase indicated by the black pointer creeping towards the red pointer (third photo). 
 

 

It’s probably best done with the heating off, but I don’t know. 
 

The fact the pressure has gone from the expansion vessel is indicative of a leak somewhere. 

[canalsiderenovation]

10 minutes ago, Russdl said:

The fact the pressure has gone from the expansion vessel is indicative of a leak somewhere. 

 

That is odd as we only had the system serviced 2 weeks ago... maybe it is a problem with the expansion vessel?

[Russdl]

Maybe. Pretty unlikely I would think - but I’m no expert. 

[Beelbeebub]

2 possibilities

 

You have a leak somewhere

 

You may have an issue with the expansion vessel (red tank) 

 

First check the expansion vessel

 

When the pressure is near zero, like in the first picture, get a tyre pressure gauge and read the pressure in the red cylinder. There should be a valve exactly like a car tyre one on the top. It should be something like 0.7bar, 1 bar or similar. 

 

If it has pressure eg 0. 7bar but the gauge on the water reads near zero, it is possible you have a leak somewhere. 

 

If it reads near zero your expansion vessel has lost has pressure (you may still ha e a leak but it's a bit less likely) 

 

If the latter you can pump it up with a.tyre or bicycle pump. 

 

Then top it up with the flexi hose. 

 

You need to turn the. Slotted screwdriver thing so it's. Inline withe the pipe, then turn the black handle at the other end.  There should be a whooshing sound and the pressure creep up. Once at desired. Level (1 - 1.5bar) turn both valves off and disconnect the pipe (get a saucepan under as some water will come out. 

 

Beware just topping up the pressure continuously. The water is going somewhere! 

 

[canalsiderenovation]

I don't own a tyre pressure gauge but I have ordered one from Amazon for delivery tomorrow.

 

I have now added pressure back in for now. The other half mentioned at the service the guy mentioned something about 'that red tank' and that it may need replacing so I am guessing it may be an expansion tank issue! That all said we have not had it serviced for about 4 years and I would likely get a different company if it does need replacing and get a different opinion...

[Nickfromwales]

The pipe shouldn’t be disconnected, in real life nobody removes these ‘temporary links’, as there’s no blank cap for the cold supply to be made safe with. 
 

Most fitters pull these blank caps off their rubber noose and throw them away, to save explaining what they’re for.

 

Eg

 

[Nickfromwales]

2 minutes ago, canalsiderenovation said:

I don't own a tyre pressure gauge but I have ordered one from Amazon for delivery tomorrow.

 

I have now added pressure back in for now. The other half mentioned at the service the guy mentioned something about 'that red tank' and that it may need replacing so I am guessing it may be an expansion tank issue! That all said we have not had it serviced for about 4 years and I would likely get a different company if it does need replacing and get a different opinion...

What a prick.

 

The whole point of the chuffing “service” is to inspect and top up the expansion, if so required!!!!!!

 

Did he do the G3 inspection for the UVC? That’s the major importance here. 

 

I’d not let him back through the door ever again, as he’s gone the easy route and just wandered off with some fast bucks.

 

When you find a replacement, fit one of these to the red expansion vessel. 
 

 

and if you want to make life easier downstream you can fit one to the UVC expansion (usually a white vessel a-la your red one) so the next service chap won’t wince and will be minutes vs hours checking both of these vessels accordingly, per annum. 

[JohnMo]

10 minutes ago, canalsiderenovation said:

don't own a tyre pressure gauge but I have ordered one from Amazon for delivery tomorrow

If your checking the pressure of the expansion vessel, you need to depressurise it, otherwise you are just reading system pressure. Ideally it will have an isolation valve and bleed point at the expansion vessel to allow this test. Otherwise it's a pain.

 

Overlapped post with @Nickfromwales

Edited 17 hours ago by JohnMo

[Nickfromwales]

1 minute ago, JohnMo said:

If your checking the pressure of the expansion vessel, you need to depressurise it, otherwise you are just reading system pressure. Ideally it will have an isolation valve and bleed point at the expansion vessel to allow this test. Otherwise it's a pain.

 

Overlapped post with @Nickfromwales

Yours was more eloquent.   

[JohnMo]

1 minute ago, Nickfromwales said:

Yours was more eloquent.   

Your more correct the guy is a kn0b and shouldn't be let through the door.

[Nickfromwales]

2 minutes ago, JohnMo said:

Your more correct the guy is a kn0b and shouldn't be let through the door.

🤣

[Beelbeebub]

1 minute ago, JohnMo said:

If your checking the pressure of the expansion vessel, you need to depressurise it, otherwise you are just reading system pressure. Ideally it will have an isolation valve and bleed point at the expansion vessel to allow this test. Otherwise it's a pain.

If the system pressure target is 1.5bar when cold, then your pressure vessel should be at a little bit below (say 1.4bar) when empty. This allows a little water into the vessel when at system pressure and the maximum volume change when hot. 

 

So if your water pressure gauge shows 0.2bar your vessel should show 1.4bar.  Of it shows lower then the pressure is wrong. 

 

You can top it up but the fact the air has been lost points to a failure in either the valve or the internal membrane. 

 

If some water comes out of the valve, your membrane is almost certainly shot. 

 

Swapping the vessel is the easiest. 

 

 

[ProDave]

When booking the next person, say you want a "G3 service"  If they mumble, pause, or say "what" they are not the right person.

 

Before that, when the system is next cold and reading 0, you could try reading the pressure at the valve on the top with a car tyre pressure gauge and tell us what reading you get.

 

It might just need topping up.

[canalsiderenovation]

20 minutes ago, Nickfromwales said:

What a prick.

 

The whole point of the chuffing “service” is to inspect and top up the expansion, if so required!!!!!!

 

That’s the major importance here. 

 

I was not around, I booked the service but was not here when they did it. This is supoosed to be a reputable firm, indeed it has been around for a while and locally comes recommended  OH said guy filled in lots of paperwork and said we would be emailed it along with a copy of the invoice but it may be a while as they were busy. What happened next was radio silence and then on about day 12 a snotty typed letter and invoice that we hadn't paid reminding me of their terms. Turns out they had taken my email address wrong which is why I had not received it. Needless to say I tore a strip off them, they apologised, I paid and that was that but I never did receive any paperwork from the service (probably because it was sent to my wrong email). I have followed this up this morning.

 

I can see from the invoice that it does say a certificate will be supplied on receipt of payment but I haven't had one.

Edited 17 hours ago by canalsiderenovation

[SimonD]

2 minutes ago, ProDave said:

When booking the next person, say you want a "G3 service"  If they mumble, pause, or say "what" they are not the right person.

 

It's quite funny you say this. In three years I have only been asked once for an unvented service and that turned out to be because the bubble needed to be recharged on a MegaFlow, queue twiddling my thumbs for 45 minutes listening to bubbles in the cylinder and a customer repeatedly asking me if I was okay. When I service a boiler and they have an unvented cylinder I always tell the customer that it needs an annual service and they shrug because they don't even want to pay for the boiler to be serviced. They don't even ask me how much the unvented service would cost. 

[Nickfromwales]

1 minute ago, SimonD said:

 

It's quite funny you say this. In three years I have only been asked once for an unvented service and that turned out to be because the bubble needed to be recharged on a MegaFlow, queue twiddling my thumbs for 45 minutes listening to bubbles in the cylinder and a customer repeatedly asking me if I was okay. When I service a boiler and they have an unvented cylinder I always tell the customer that it needs an annual service and they shrug because they don't even want to pay for the boiler to be serviced. They don't even ask me how much the unvented service would cost. 

Yup. But they probably don’t check the oil in the car either, then moan when a £4k bill lands to fix it. 

[SimonD]

43 minutes ago, Nickfromwales said:

Yup. But they probably don’t check the oil in the car either, then moan when a £4k bill lands to fix it. 

 

Very true -it's like the ones who call to book in a service because the boiler isn't working right. They say they're surprise as it was only done recently while the paperwork says 7 years ago!

[canalsiderenovation]

Paperwork just come on email, seems we may need to get expansion tanks replaced!

 

 

Edited 16 hours ago by canalsiderenovation

[canalsiderenovation]

And quote.

 

[ProDave]

https://www.screwfix.com/p/flomasta-potable-expansion-vessel-24ltr/131kk

 

£40 each from Screweys, so that makes it £310.40 for labour (including the VAT)

 

How long did they say they would take and how many people?