Vaillant Eco Tec 824 pressure increasing on heating

[abc_plumb]

Need some help on a Eco Tec Plus 824.
pressure keeps increasing to over 2.5 and over 3bar when the heating is on.
Pressure drops back down when the heating cools down.
I suspected the vessel tank, as its also this when its happened in the past.
I've received the expansion vessel but the customer has called back saying its the same.
Only a year ago I've powerflushed the system which took over 9 hours.
Any idea if anyone has come across this fault.

 

[dave1]

Have you fitted the new vessel? How long ago?

 

[lame plumber]

? received the expn vssl

 

[abc_plumb]

Sorry,
I've fitted a new expansion vessel, but still the same fault.
I got a call from the customer a day after I fitted a new vessel.

 

[TBServices]

Sorry,
I've fitted a new expansion vessel, but still the same fault.
I got a call from the customer a day after I fitted a new vessel.

Internal vessel? I'd be checking the pipe/flexi for blockage

 

[abc_plumb]

It's a copper pipe which is connected to the vessel pipe, not a flexi.
but I think I will have to look at that copper pipe.

 

[TBServices]

It's a copper pipe which is connected to the vessel pipe, not a flexi.
but I think I will have to look at that copper pipe.

Easiest way to check its clear is to pump up the expansion vessel and see if pressure increases on gauge.

 

[abc_plumb]

What do you guys use to pump and check the pressure on a expansion vessel.
I've got a Rothamburger air gun but the gauge on it never show the correct pressure.
I've also purchased a Goodyear electronic gauge, but when I connect that to the vessel it releases the pressure. Can anyone suggest something with details pls

 

[TBServices]

I just have a floorstanding bike pump, similar to the regin jobbie, and a pressure gauge I got from a car shop. Not electric.

 

[abc_plumb]

Any pictures?
does it lose pressure when you swap for the gauge

 

[zeebeedee]

A cheap foot pump and a tyre pressure gauge for £3 from halfords

 

[jefaz]

i seem to be changing an awful lot of vessels lately!
mainly on duo tec and platinum boilers!!

 

[abc_plumb]

A cheap foot pump and a tyre pressure gauge for £3 from halfords

The problem with these tyre gauges, is when you remove the pump, and insert the gauge you end up losing some pressure.

Anyone use the regin vessel pump? (model number: REGK30)

 

[dave1]

The problem with these tyre gauges, is when you remove the pump, and insert the gauge you end up losing some pressure.

Anyone use the regin vessel pump? (model number: REGK30)

Yes I am a very good sturdy pump in my opinion. Ill always charge just over the recommended charge so when you remove it it will be right.

 

[zeebeedee]

The problem with these tyre gauges, is when you remove the pump, and insert the gauge you end up losing some pressure.


Anyone use the regin vessel pump? (model number: REGK30)

Just give it an extra few pumps before you test it

 

[buckley plumb]

Internal vessel? I'd be checking the pipe/flexi for blockage

i agree . you could open the prv or drain off and over pressure the exp vessel to clear it but be careful i had a duotec clear and block plate to plate which the crap that was in the exp vessel pipe

 

[arran197]

What you need to do is isolate and drain, or just drain the boiler. Connect your foot pump or bike pump to the expansion vessel and inflate to 1.2 BAR. Disconnect the pump and check the pressure with a good gauge. Reduce the pressure in the vessel to what it says on the side. They are normally 1 BAR, but some are 0.75 BAR. Refill the system and test.

Even if you fitted a new vessel, did you check the pressure was correct before you fitted it? If someone has let the air out of it, it won't do it's job.

Similarly, if the pipe connecting the vessel to the rest of the system is blocked, there won't be any expansion.

If the customer reports that the pressure is only going down rather than going up then down, the prv is the most likely cause. If it's been releasing water on a regular basis whilst the old vessel was faulty, then there's a chance the rubber seat will be damaged, split or just not seating correctly. If it is the case that the pressure is only going down, not up, then take the prv out and clean the insides thoroughly, use some silicon grease and put it back together. Or simply change it for a new one.

 

[abc_plumb]

There's no issues with the prv, as the pressure is not being topped up via the filling loop. When the heating is on its increases when the heating is turned off is returns to the pressure it started with.
Thanks for the advise.
Did think of checking the pressure of a new vessel tank.

 

[abc_plumb]

Didn't

 

[buckley plumb]

There's no issues with the prv, as the pressure is not being topped up via the filling loop. When the heating is on its increases when the heating is turned off is returns to the pressure it started with.
Thanks for the advise.
Did think of checking the pressure of a new vessel tank.

if its reaching 3 bar and not blowing off outside you have a real safety issue