Re-pressurise Vaillant Thermocompact

[TBag]

I have a Vaillant Thermocompact which has reduced to 0 Bar pressure. Whenever it starts up there is a banging sound for a few minutes, but this dies away and it does actually work for both heating and hot water, but the noise is clearly not right and I think associated with the zero pressure. I only have the unhelpful advice from the manual about consulting the non existent installer's instructions about how to fill the sysytem. I have looked at the nearest current equivalent manual for the ecoTec Pro which talks about opening the valve on one of the 4 pipes underneath the bolier to let in water. Unfortunately, my boiler only has 3 pipes leading to it. The middle one is the gas pipe and the outer 2 are water, but all 3 already have their vales in the open position. At the far right is a 3 bar pressure relief valve. I think my system refil must be somewhere else, but where do I look for it and what does it look like? I have a utility cupboard that houses the enormous hot water tank with a smaller pressure vessel above it and a mass of piepwork and lever valves that interconnect all this (including a water softener and a large pressure pump to provide high pressure water to all our taps) - it's more complex than the Tornado I fly for a living! So before I do somethging terminal and twiddle the wrong valve, and before I resort to a plumber, can anybody suggest how I might refill the system to get pressure back in to my boiler.

 

[mrgas]

Have you seen a silver braided hose about 1/2 inch either below the boiler or in your tornado cupboard?

 

[TBag]

There is no braided pipe leading to the boiler itself - only the 3 solid pipes. In the utility cupboard the only 2 braided pipes seem to be there to get a couple of the multifarious pipes round corners. One goes up to the small expansion? tank above the main tank - it seems empty when tapped by the way. Not much help I know, but there are several pipes with lever valves on them - I imagine that if one of them was the refill circuit I'm searching for it might be one with a closed valve? Some of the pipes disappear under the floor as they come from the boiler 2 rooms away - you can feel the hot pipes through the floor of the kitchen.

 

[mrgas]

Any chance of a photo?

 

[kevplumb]

 

[TBag]

The picture kindly posted by kevplumb is exactly one of the pipes I have in the cupboard and it leads to a pipe that disappears under the floor. It's valve is in the off position, I just tentatively opened it a bit and I can hear water flowing - it also runs my pressure pump that runs whenever any of our taps are turned on. Do you think if I open this valve it will pressurize the boiler - if so how long do I turn it on for?

Great help by the way - thanks - this is the most progress I've made in days!

 

[kevplumb]

go gerr it floyd but keep an eye on the gauge

 

[TBag]

Mr Gas and Kevplumb you are both brilliant! I turned off the pressure pump and turned on the valve on the braided hose while my son watched the pressure guage. I have charged it to 1.5 bar and now hope that the pressure stays there and the banging on start stops. Is it normal for the pressure to decay? How often should I plan on doing this? Anyway, I'm at least better off than I was and will monitor it for a while.

Thanks for maintaining the "special Relationship" Kev - I believe 'You rock' is a suitable transatlantic expression of appreciation!

T-Bag

 

[kevplumb]

Thanks for maintaining the "special Relationship" Kev - I believe 'You rock' is a suitable transatlantic expression of appreciation!

Is it normal for the pressure to decay? How often should I plan on doing this?

check it every 3 months

give over i was born in the north east of england

but i appreciate the sentiment