Ideal Mini C28 losing pressure on Central Heating

[stget02gt]

Central Heating working ok, but keep losing pressure and need to refill using filling loop. Problem only seems to occur when central heating being run and possibly at the same time as DHW. No apparant leaks on CH loop or water coming out of condensing overflow? Any ideas....please

 

[Simon F]

how much are you needing to refill, how often?
what pressure does the system get to when hot?
have you checked for leaking at the prv?

 

[e/bourneplumber]

pressure in the expansion vessel?

 

[merv]

There could be several possabilities. Pressure relief passing, Expassion vessel deflated or ruptured or leak from pipework under floor.

I would look at the expansion vessel first. If you are lucky, it may just need pumping back up.

 

[diamondgas]

IMHO it all depends on how long it's taking for the pressure to drop, however, watch the pressure gauge from cold.... If it rises to 3bar when heating on then EV most likely!

 

[stget02gt]

IMHO it all depends on how long it's taking for the pressure to drop, however, watch the pressure gauge from cold.... If it rises to 3bar when heating on then EV most likely!

Thank you for the replys. I need to go through the different options.
Can you explain what it means to repump the expassion vessel?

 

[diamondgas]

Thank you for the replys. I need to go through the different options.
Can you explain what it means to repump the expassion vessel?

If you're not sure of the components on your boiler, their purpose or position then explaining how to re-pressurise the expansion vessel may be somewhat problematic ... It's not that big a job TBH and shouldn't cost you a great deal to get someone out to do. However it could cost you a lot more if you mess it up IMO! How confident are you at undertaking this task? For me it's important that I know you know what your doing I'd hate for you to make hash of it, fry your boiler or set leaks about the place

 

[stget02gt]

If you're not sure of the components on your boiler, their purpose or position then explaining how to re-pressurise the expansion vessel may be somewhat problematic ... It's not that big a job TBH and shouldn't cost you a great deal to get someone out to do. However it could cost you a lot more if you mess it up IMO! How confident are you at undertaking this task? For me it's important that I know you know what your doing I'd hate for you to make hash of it, fry your boiler or set leaks about the place

I have some experiance of halstead combi boilers however i have not come across the term to repump the expansion vessel is the idea to get rid of any air locks?. I understand the principle of the sealed systems and using the filling loop. I have downloaded the manual and it looks like the expansion vessel is at the back near the top. I plan to get the boiler serviced and checked anyway however i would just like to understand the mechanics a bit so that i can discuss the situaton with the heating engineer and give him some information in advance.
thank you for your advice so far.

 

[stget02gt]

I have looked further down the the C28 manual and i can now see where the EV lives. Do the EV's come already pressurised? (possible stupid question)

 

[Brendan Rodgers]

Your E.V. is like a car tier, it can go flat, if it dose your heating pressure will go up over 3 bar and then release through the safety valve outside, or it may not go up much if the safety valve starts passing straight away as it will compensate for the increase.
It,s designed to absorb the pressure when getting hot, the boiler needs isolating and draining with the drain point left open, then a pump fitting to the top of it and pumping up to about 0.9 of a bar.
This isn't for removing air locks just to recharge the vessel back to new condition.
Hope this helps..

 

[Brendan Rodgers]

Sorry,, YES it dose come already charged but as said above, can go down on you (deluxe model)...:clap: