mystery pressure loss.

[desrob]

baxi duo tec combi he, 24kw, losing pressure, filling up every other day,no obvious signs,any ideas.

 

[grahamgas]

Pump up pressure and isolate flow and return valve, to see if you still get the drop.

 

[desrob]

doing that tomorrow

 

[diamondgas]

Hi desrob ... You've gotto check the expansion vessel 1st to rule it out ... should be around 0.7Bar atmospheric! If it's lost it's charge it'll give the symptoms mentioned

 

[desrob]

Pump up pressure and isolate flow and return valve, to see if you still get the drop.

when you say pump up do you mean fill up to say 3-5 bar then isolate and leave for a couple of hours or more or do you mean pump up ev

 

[desrob]

Hi desrob ... You've gotto check the expansion vessel 1st to rule it out ... should be around 0.7Bar atmospheric! If it's lost it's charge it'll give the symptoms mentioned

yes mate done that ...ok

 

[grahamgas]

Yeah just top up through the filling loop to 2bar

 

[arran197]

Could be the heat ex, going through the condense. Not seen it before and I work on them all the time, but possible. I had 1 the other day and there was a very slight leak in the loft on a thumb vent causing the pressure lose.

 

[diamondgas]

If it's every other day and the EV is charged thats quite a bit of water loss desrob.... As sugested pressurise and turn off the iso's ... also check out the condensate trap/pipes. Obviously the pipe from the HEX should only be running water when the boiler is on. If running when off then its the main hex yeh?

 

[desrob]

If it's every other day and the EV is charged thats quite a bit of water loss desrob.... As sugested pressurise and turn off the iso's ... also check out the condensate trap/pipes. Obviously the pipe from the HEX should only be running water when the boiler is on. If running when off then its the main hex yeh?

yeah i was going to ask you were this lost water is going if the ev is charged or not,condensate operating normally

 

[Mbear]

Could be the heat ex, going through the condense. Not seen it before and I work on them all the time, but possible. I had 1 the other day and there was a very slight leak in the loft on a thumb vent causing the pressure lose.

That's what my money's on

 

[desrob]

That's what my money's on

heat ex or vent, don't even know what a thumb vent is and why in the loft ?

 

[diamondgas]

yeah i was going to ask you were this lost water is going if the ev is charged or not,condensate operating normally

Not sure what you mean here desrob "condensate operating normally"? However if you mean nothing running out of it when off Then suspect the system.... However it's worth running the "iso off" check but you need your custards okay obviously! They have to put up with the inconvenience Only other possibility is a blocked supply to EV? Not impossible by-the-way

 

[Mbear]

Internal h/e Leak dribbling through condi pipe.

Although, one to check, open sys converted to sealed sys, cold feed capped at header tank. The redundant but still live cold feed developed a few hairline cracks/leaks. Trying to find the drop in pressure was a nightmare considering I didn't expect that pipe to be there never mind being live

 

[desrob]

Internal h/e Leak dribbling through condi pipe.

Although, one to check, open sys converted to sealed sys, cold feed capped at header tank. The redundant but still live cold feed developed a few hairline cracks/leaks. Trying to find the drop in pressure was a nightmare considering I didn't expect that pipe to be there never mind being live

wow...!

 

[grahamgas]

I didn't expect that pipe to be there never mind being live

I know what you mean. The laziness of some guys.
Did a powerflush last week, where thepeople had only been there a few years.
Anyway before they moved in the previous owner had installed a megaflo. They basically capped cold to the cwsc, and fitted the megaflo in place of the old vented one.
Up I goes into the loft to isolate f and e tank, and discover all of this pipework just sitting there.
Anyway whilst flush is going on, I say to the lady customer about it, and offered free of charge to remove all redundant pipes.

Kerching£££

 

[arran197]

heat ex or vent, don't even know what a thumb vent is and why in the loft ?

The pipework ran up in to the loft and fed the rads from above. It was an upstairs flat. A thumb vent it a manual vent you open to let the air out. Mainly found at the highest point on a heating system and much more common on open vented systems.

 

[buckley plumb]

any pipes in a concrete floor this prime suspect due to corrosion

 

[desrob]

The pipework ran up in to the loft and fed the rads from above. It was an upstairs flat. A thumb vent it a manual vent you open to let the air out. Mainly found at the highest point on a heating system and much more common on open vented systems.

thanks for the lesson i now know that when someone refers to a thumb vent, they are refering to a manual vent, the job of said vent is to expel unwanted air and they are placed at the highest point in the system(not sure why)or is it because air is forced upward because of the weight of the water being heavier,hence air at high points..

 

[plumbdocter72]

have you checked the pressure relief pipe when the heating is on? and when it is off .
copper pipe turned into wall on outside of building.

 

[desrob]

have you checked the pressure relief pipe when the heating is on? and when it is off .
copper pipe turned into wall on outside of building.

can you draw me a picture not sure what pipe your refering too

 

[plumbdocter72]

do you have a manual for the boiler? go outside your house and have a look. for a pipe turned into the wall.
look under boiler and see if one of the pipes is going through wall to outside size of pipe 15mm go and have look.