Quick Thoughts - Hot Water / Pressure Level?

[CJL1]

Hi.

Just looking for some quick thoughts on an issue with our boiler.
Nine years old and no real issues (not to do with the boiler itself).
Our boiler (combi) in on the ground floor, and on our second floor is an unvented water heater (large tank).
Above this tank is a small red tank with a guage on.
This guage has two readings: one with a red indicator and one with a black indicator.
The red indicator is around 1.75, and the black indicator is typically between 1 and 2.
The other day we noticed the black indicator was on zero, so I refilled with the little stop tap to 1.5. The next day, it was at zero again. I tried again yesteday, and then tonight it was on zero and the boiler was making a funny noise (more noticable on the floor below than in the airing cupboard. A little like a straining sound).

Now, by my own prefessional judgement I can conclude I havent got a clue what the guage is or what the two indicators mean.

Any ideas folks ? Please

 

[TCCHeating]

It is the pressure guage for your central heating system.

Fill the system to 1 bar when cold, then turn on your heating and watch the guage.

If it rises above 3 when the system gets hot, then the expansion vessel (the red tank) needs either recharging or replacing.

If the pressure does not rise significantly when hot, then you have a leak somewhere.

 

[CJL1]

Thanks for the reply.

If its happened a few times (and we have had a couple of leaks), and does so in the space of 24 hours, you would expect to see the leak if internal?

Or is there another route for the water to go?

Will need to check tomorrow as only just turned the heating/water off.

 

[CJL1]

I presume as well that we are watching to see if the black line goes above three, not the red line.

I did check this yesterday (I think) and after five minutes it was still in the same place.

Do I also presume that I should only turn the heating on, and not the hot water?

 

[TCCHeating]

Black needle is the pressure reading. The red needle is just an adjustable guide needle, so ignore it.

If you do the test above and there is not a big rise in pressure when hot, you have a significant leak somewhere, to lose all pressure in 24 hrs. (If there is no visible leak from ceilings then you may have a leak on the pipework below the ground floor).

It could also be a faulty heat exchanger in the boiler. (Leaking through condensate) or a faulty pressure relief valve.

To answer your last question: the heating uses the majority of the expansion vessel, but turn on both heating and hot water when testing to be extra sure

 

[CJL1]

Thanks again. Really appreciate that.

How long after turning everything off could I refill?
Just thinking if there was a leak, would it go down without the heating/HW on?

Leaks are slightly historical in this house. Three in nine years. But cannot see anything and no leaking in the airing cupboard.
If the ground floor in concrete, i'm presuming that there are no pipes here?
Is there anywhere else obvious we could check for leaks?

Thanks again for your help.

 

[TCCHeating]

Thanks again. Really appreciate that.

1. How long after turning everything off could I refill?

2. Just thinking if there was a leak, would it go down without the heating/HW on

1. Refill when the rads are cold.

2. Yes


What make and model of boiler do you have? Some boilers are more prone to heat exchanger faults than others!

 

[CJL1]

Thanks. Will refill tonight to 1 and leave it. See where it is in the morning and then put the CH/HW on and check.

Will let you know what happens in the monring.

 

[CJL1]

So the wife says why not check the garage.
Yep, by 1ft square wet patch on ceiling, wet along the joist as down the wall about 2ft.
Great. Another pipe that has come undone 😒

As it's in the garage, would it be best to go from underneath (skimmed plaster board) or from above (most likely in the lounge where we have new carpet?

So that's the dishwasher, the microwave, the laptop and now a leak. Getting fed up!