Pressure loss - potterton powermax he

[davelee212]

Hi all

I have a boiler problem and I've had a bloke out to look at it. It seems that the repair is going to set me back a fair amount so I'm just after some confirmation of what the engineer said.

Some background: I came back to find my boiler had stopped working due to low pressure. I've had to top it up before and, because there are instructions on how to do this attached to the front panel, assumed it was normal to have to do so occasionally. Anyway, so putting in a bit of water and resetting it got it back up to pressure and it worked.

It did the same thing a couple of days later. Had a look around and noticed a leaky radiator. It was quite a leak so did a temporary fix with some tape and that's held up okay. I noticed that although some radiators are getting really hot, some remain luke warm and some cold. I understood they were plumbed in on a ring from the boiler, through all the rads and back. How can some stay cold when others are really hot?

The boiler is still losing pressure though. We'll get it up to 1.5-2.0 bar and within 24 hours it's shut itself down again, presumably the pressure is getting quite low.

So I had chap and he assessed what needed doing. He reckons the rad that was leaking needs a new part to sort it properly (fair enough). As the boiler is still losing pressure (even though my temporary fix stopped the rad leaking) he reckons the pressure relief valve and TPR on the boiler need replacing. He showed me a drip of water coming out the bottom of the TPR. It would appear to be rated for 3bar and the pressure reading on the boiler was at 1.6bar, so I guess it shoudn't be dripping. He also reckons the bottom of the condensate trap is dirty which means the system needs flushing.

Below is a pic I've taken of the boiler with the cover off. In yellow are the bits chap said need replacing. The black bit in the bottom right is the TPR but what is the red bit? Is that another relief valve of some kind? Highlighted in blue is the bit that is apparently dirty and points to it needing flushing. I didn't really see any dirt on that pipe although he may have taken it off to look inside when I wasn't there. The water that was leaking out of the radiator looked clean so is there any need for a flush? How much would you expect to pay to replace the TPR and relief valve and replace the leaky section on the rad where the (what I think is hep2o pipe) connects into the valve end of the rad?

Also, unrelated but just out of interest, highlighted in green is the part that allows me to put more water in. Would I be right in thinking that this is adding water via the cylinder return pipe? What is the grey plastic pipe on the bottom? Is this the return from the central heating circuit? Which would be the flow pipe from the ch circuit? The one to the left on the condensate trap?

thanks for reading the long winded post and thanks in advance for any advice! Just want to understand a little more how this stuff works!

Dave

 

[moony]

adding water from mains mate into the flow or return. (green box)

hard to give a price but to replace valve on rad 50-100 depending on a few things
changing pressure relief valve 80-120
bottom of condense is dirty so needs a flush ?haha
prob no more than 150-200 depening on a few things

other more experienced lads will have more of idea on the cost of parts etc.

 

[WOLDEN]

dirt in condense is not a indercation a flush is needed , its dirt sucked in from the air in take .

 

[davelee212]

So it seems that a flush is probably unneccessary and probably the bulk of the cost I've been quoted. Out of interest, what would indicate that it needs flushing? When the radiator was at it's worst (leaking a couple of litres a day) the water collecting in the saucepan was clean. I'm not sure how any dirtiness would have got in as it's clean mains water.

Dave

 

[Cds]

Why did the radiator start leaking?

If it is leaking from a connection i.e. around the valve tail threads then OK. But if it is a hole in the radiator (pin hole) then this will have been caused by corrosion. If this is the case then I would suggest a flush is necessary and then when refilled make sure a system inhibitor is added.

 

[davelee212]

The radiator is fed from 10mm plastic piping. The leak is from the pushfit connection that the pipe goes into on the TRV side of the radiator.

It's only just 5 years old so surely the radiators won't be rusting inside already will they? The water coming from the leak is clear though, wouldn't it be a red-brown colour if it were rusty inside?

I'm having someone over Tuesday for a second opinion so I'll see what he says.

Dave

 

[moony]

The radiator is fed from 10mm plastic piping. The leak is from the pushfit connection that the pipe goes into on the TRV side of the radiator.

It's only just 5 years old so surely the radiators won't be rusting inside already will they? The water coming from the leak is clear though, wouldn't it be a red-brown colour if it were rusty inside?

I'm having someone over Tuesday for a second opinion so I'll see what he says.

Dave

dirty water is a sign of a flush needed, but bear in mind water that is being pumped around will be pretty clean take a rad off and tip up to see the dirty stuff in bottom of rad.

the more it leaks the more you fill up - the more you fill up the more oxygenated water entering the system which causes more corrosion so in answer if youve been topping up the water for five years then yeah your going to have problems matey

 

[heinz57]

Rads can rust out in weeks if there is no rust inhibitor in the system, and it sounds to me that yours has been throughly flushed out. Mention this to the chap and make sure he puts more in the system. If you need a powerflush then feel the rads when they are on, if the heat is patchy in places then this is a good indication that you need a flush, best of luck mate. Flush can be about £450 depending on the number of rads on your system and its an all day job, do not use British Gas!