please help - modena 80e pressure 0 for no reason

[kirstynurse]

hi ,

i have had an ongoing problem with my modena 80E firrolie boiler. when heating is on its ok then whens its off the pressure drops to zero. water is coming from the pipe outside so have had the expanssion vessel and prv valve changed but it still has no pressure.

is there anything else it could be - no obvious leaks and i would have thought that that amount of water would be obvious as it goes from 1.5 to 0 overnight

it is costing me a fortune and now my plumber says we will need a new boiler - what else could be wrong? also had automatic air vent changed

 

[holty]

leek on system also when EV was changed was the pipe to it checked for blockage.

 

[kirstynurse]

thanks. i'll ask my plumber as he changed ev but i would hope he did!!

not sure if its relevent but all this as seemed to happen once we got boiler serviced and our bathroom redone - but this could just be coincidence

 

[holty]

when the bathroom was done was a towel rad put in or rad changed etc.

 

[Kingfisher3]

ask your plumber if he checked the pressure on the EV before he refilled the system. Use a tyre pressure gauge. If that is Ok I would also be looking for a block as hotly says. The problem is in that area. Get a second opinion before you get another boiler. Ask about and find someone with a good reputation not someone with a big advert.

 

[kirstynurse]

holty,

yes they did put a towel rad in - could this be the problem?

kingfisher - the ev was barnd new so surely the pressure on it should be ok or does it stil need checking?

 

[Agile]

I recently saw an installation by a contractor to Heatserve who fitted a new EV without setting the pressure to suit the system. A British Gas engineer then attended and said it needed power flushing but he also failed to check and reset the EV pressure.

Some people are either pretty incompetent or just plain lazy. I expect most are the former!

Tony

 

[Kingfisher3]

It takes 2secs to check when your installing and at most half hour when the system has been charged. but it's easy to forget when your in a hurry. It cost nothing to do a check. How much is a new boiler?

 

[kirstynurse]

ok update - no longer is there water coming from pipe outside however my pressure was ok fro 24 hrs as suspected and then dropped to just above 0 in a matter of hours now

so i guess prv and expansion vessel now working - couldn it just be the pressure gauge is faulty as nothing is leaking

 

[scatmanjohn]

ok update - no longer is there water coming from pipe outside however my pressure was ok fro 24 hrs as suspected and then dropped to just above 0 in a matter of hours now

so i guess prv and expansion vessel now working - couldn it just be the pressure gauge is faulty as nothing is leaking

You have got a leak...find it...repair it....end of pressure problem.

Where have you searched for the leak so far?

 

[Kingfisher3]

Don't think so. Try this. Fill the system back up to 1.0bar. turn on the heating. See if the gauge starts to climb anywhere near 3.0bar. If it does look at the pipe outside, you will see water coming out. What happens is that water is expanding as it heats it can't push against the pressure vessel so it escapes out through the PRV. As the water cools the volume decreases but it has lost some of its volume through the PRV hence less water in system no pressure. The only thing that is not working is the pressure vessel.

 

[kirstynurse]

have so far searched all rads - under floor boards of hall and bedroom - any visible cieling etc and pipe outside - it is deffinately not coming from that (anymore!!)

 

[Agile]

Have you put a bottle, condom or plastic bag over the pressure release valve vent outside to see if there is any evidence of any leaking over a full 24 hour cycle?

What does happen when you do what has been asked above ???

Tony

 

[kirstynurse]

sorry meant to say i have done that and orriginally it collected alot of water but the expansion vessel and pressure relief valve have now been changed and it no longer collects water

 

[Kingfisher3]

if you are 100% sure that the water is not venting through the PRV then you must have a leak. But the ultimate cause could still be the pressure vessel. I had this in a Pub recently took 2 months to find leak, cleaner kept mopping it up before I got there. wound pressure up to 3bar and waited for the staff to call me.