DeDietrich boiler: water pressure sensor or not?

[MikeH]

I have a DeDietrich wall-hung boiler (model: CITY 1.24/II).

The water feed comes in via a valve, pressure limiter then T-piece with pressure gauge -- showing 2bar.
There is a pressure gauge on the outflow from the boiler to the rads/taps - also showing 2bar.
But the boiler itself shows only 0.5bar (red LED). I know the other (green) LEDs work, because they have a secondary function (re configuration).

So superficially, it seems to suggest the boiler's water pressure sensor or the sensor circuitry is faulty.

But curiously...
There are two small valves in the brasswork under the boiler, and the manual states that they should both be opened to top-up the water. That seems a tad strange; it looks like one is for topping-up and the other for draining-off if over-pressured (it leads to an overflow pipe) [see attached image]. Anyway, whether I open one or both of those, nothing happens - no hint of pressuring/inflow noise (OK - maybe it has equilibrated at 2bar) and no drain-out (oo - perhaps that low pressure LED is correct pressure?).

Any thoughts?
What is wrong, what to do aboutit?

Thanks for your thoughts,
Mike

 

[Gas]

It's not strange at all, that is the filling loop.

When did you last have an annual service on this?

 

[MikeH]

Thanks for having a look.

It has not had a service since installation (new) four years ago.

I should perhaps say that it is a neighbour's, rather than mine.
He also confirmed that it ran OK today - the red LED status did not prevent it.

 

[Gas]

Thanks for having a look.

It has not had a service since installation (new) four years ago.

I should perhaps say that it is a neighbour's, rather than mine.
He also confirmed that it ran OK today - the red LED status did not prevent it.

The best advice you are ever going to get is not to go any where near it and advice them to get a carbon monoxide alarm.

If your neighbour gets carbon monoxide (CO) poisoning due to it not being serviced, who are they going to be looking at, the last person who touched it.

 

[MikeH]

OK. Yes, proper servicing advised.
The boiler is in a separate building outside, and they have CO- and fire alarms.

 

[Ermintrude]

Just because it's In a separate building negates no requirement for safety or excuses poor service. It's always a friend or neighbour who finds the bodies as well!

 

[MikeH]

I will try to ensure the owner gets the boiler serviced.

I would still like to understand the filling loop, however...
You will appreciate from the diagram that the system is of a type that does not allow insertion of a flexible loop between two valves. There is a rigid feed pipe, with manual valve, regulator and gauge that connects the mains water supply permanently to the boiler. The water enters through one valve, passes through some brasswork where it enters the boiler proper; then there is another identical-looking valve after which a short pipe routes water to an open overflow outlet.

Insights into the operation of this would be appreciated, especially (like I posted originally) why the recommendation is to open both valves (ie. all three valves in the overall system) in order to top-up the system. Please feel free to ignore the fact that this is a DeDietrich system, and speak in general terms.

Insights into why that might not actually be working in this particular instance also appreciated.

Mike

 

[Ermintrude]

The other valve is the pressure relief valve (blow off) and is connected to the ch side of the filling loop. Integral loops are all the rage on medium range boilers.its not working as the check valve has stuck in closed postion. Needs a strip down or a replacement .

 

[AWheating]

tell them to get an external filling loop fitted by the guy who services the boiler.

 

[Ermintrude]

But that would be a lot cheaper and easier, with a boiler like that who wants the cheap and easy fix?

 

[MikeH]

tell them to get an external filling loop fitted by the guy who services the boiler.

You mean to bypass the integral loop, presumably (no point in having it in series), and tap/tee into the return somewhere? Yes - I get the idea. Thanks for that.

But that would be a lot cheaper and easier, with a boiler like that who wants the cheap and easy fix?

Though it might not actually be a fix; the pressure sensor could still be at fault (both pressure gauges reading 2bar).